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  + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_0_0/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_0_0/content.html new file mode 100644 index 0000000..42493f7 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_0_0/content.html @@ -0,0 +1,104 @@ + + + + + +Content + + + + + + + + + + +
Overview
+ + + + + + +
+ + + + + +
+ As the enterprise grows beyond a + single location, it is necessary to interconnect the LANs in the + various branches to form a wide-area network (WAN). This module + examines some of the options available for these interconnections, + the hardware needed to implement them, and the terminology used to + discuss them.

+ There are many options currently + available today for implementing WAN solutions. They differ in + technology, speed, and cost. Familiarity with these technologies + is an important part of network design and evaluation. +

+

+ If all data traffic in an enterprise + is within a single building, a LAN meets the + needs of the organization. Buildings can be interconnected with + high-speed data links to form a campus LAN if data must flow + between buildings on a single campus. However, a WAN is needed to + carry data if it must be transferred between geographically + separate locations. Individual remote + access to the LAN and connection of the LAN to the Internet are + separate study topics, and will not be considered here.

+

+ Most students will not have the + opportunity to design a new WAN, but many will be involved in + designing additions and upgrades to existing WANs, and will be + able to apply the techniques learned in this module.

+

+ Students completing this module should + be able to:

+
    +
  • + Differentiate between a LAN and WAN
    • +
  • + Identify the devices used in a WAN
    • +
  • + List WAN standards
    • +
  • + Describe WAN encapsulation
    • +
  • + Classify the various WAN link options
    • +
  • + Differentiate between packet-switched + and circuit-switched WAN technologies +
    • +
  • + Compare and contrast current WAN + technologies
    • +
  • + Describe equipment involved in the + implementation of various WAN services
    • +
  • + Recommend a WAN service to an + organization based on its needs
    • +
  • + Describe DSL and cable modem + connectivity basics
    • +
  • + Describe a methodical procedure for + designing WANs
    • +
  • + Compare and contrast WAN topologies
    • +
  • + Compare and contrast WAN design models
    • +
  • + Recommend a WAN design to an + organization based on its needs
    • +
+

  

+
+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_0_0/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_0_0/index.html new file mode 100644 index 0000000..661f2c2 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_0_0/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_0_0/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_0_0/media.html new file mode 100644 index 0000000..c8180b2 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_0_0/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/buttons.html new file mode 100644 index 0000000..9e8cce9 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/buttons.html @@ -0,0 +1,106 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + +
+ \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/content.html new file mode 100644 index 0000000..546da63 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/content.html @@ -0,0 +1,135 @@ + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.1 + WAN Technologies Overview 
  + 2.1.1 + WAN technology 
+ + + + + + +
+ + + A WAN is a data communications network that operates beyond the + geographic scope of a LAN. One primary difference between a WAN and a + LAN is that a company or organization must subscribe to an outside WAN + service provider in order to use WAN carrier network services. A WAN uses data + links provided by carrier services to access the Internet and connect + the locations of an organization to each other, to locations of other + organizations, to external services, and to remote users. WANs + generally carry a variety of traffic types, such as voice, data, and + video. Telephone and data services are the most commonly used WAN + services.

+ + Devices on the subscriber premises are + called customer premises equipment (CPE). + The + subscriber owns the CPE or leases the CPE from the service provider. A + copper or fiber cable connects the CPE to the service provider’s + nearest exchange or central office (CO). This cabling is often called + the local loop, or "last-mile". A dialed call is connected locally to + other local loops, or non-locally through a trunk to a primary center. + It then goes to a sectional center and on to a regional or + international carrier center as the call travels to its destination. +

+

+ + + In order for the local loop to carry data, a device such as a modem is + needed to prepare the data for transmission. Devices that put data on + the local loop are called data circuit-terminating equipment, or data + communications equipment (DCE). The customer devices that pass the + data to the DCE are called data terminal equipment (DTE). + The DCE + primarily provides an interface for the DTE into the communication + link on the WAN cloud. The DTE/DCE interface uses various physical + layer protocols, such as High-Speed Serial Interface (HSSI) and V.35. These protocols establish the codes and + electrical parameters the devices use to communicate with each other. +

+

+ + + WAN links are provided at various speeds measured in bits per second + (bps), kilobits per second (kbps or 1000 bps), megabits per second + (Mbps or 1000 kbps) or gigabits per second (Gbps or 1000 Mbps). The + bps values are generally full duplex. This means that an E1 line can + carry 2 Mbps, or a T1 can carry 1.5 Mbps, in each direction + simultaneously. +

+

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

Introduction to WAN Technologies

+ + http://www.cisco.com/univercd/cc/td/ + doc/ cisintwk/ito_doc/ introwan.htm

+ +

+

+
+
+

+       +        + +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/media.html new file mode 100644 index 0000000..c230763 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_1/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/buttons.html new file mode 100644 index 0000000..4b55e15 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/buttons.html @@ -0,0 +1,109 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/content.html new file mode 100644 index 0000000..944ee5a --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/content.html @@ -0,0 +1,183 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.1 + WAN Technologies Overview 
  + 2.1.2 + WAN devices 
+ + + + + + +
+ + + WANs are groups of LANs connected together with communications links + from a service provider. Because the communications links cannot plug + directly into the LAN, it is necessary to identify the various pieces + of interfacing equipment. +

+ LAN-based computers with data to transmit send data to a router that + contains both LAN and WAN interfaces. + + The router will use the Layer 3 address information to deliver the + data on the appropriate WAN interface. Routers are active and + intelligent network devices and therefore can participate in network + management. Routers manage networks by providing dynamic control over + resources and supporting the tasks and goals for networks. Some of + these goals are connectivity, reliable performance, management + control, and flexibility.

+

The communications link needs signals in an appropriate format. For + digital lines, a channel service unit (CSU) and a data service + unit (DSU) are required. The two are often combined into a single + piece of equipment, called the CSU/DSU. The CSU/DSU may also be built + into the interface card in the router. +

+

A modem is needed if the local loop is analog rather than digital. + Modems + transmit data over voice-grade telephone lines by modulating and + demodulating the signal. The digital signals are superimposed on an + analog voice signal that is modulated for transmission. The modulated + signal can be heard as a series of whistles by turning on the internal + modem speaker. At the receiving end the analog signals are returned to + their digital form, or demodulated.

+

When ISDN is used as the communications link, all equipment + attached to the ISDN bus must be ISDN-compatible. Compatibility is + generally built into the computer interface for direct dial + connections, or the router interface for LAN to WAN connections. + Older equipment without an ISDN interface requires an ISDN + terminal adapter (TA) for ISDN compatibility.

+

+ Communication servers concentrate dial-in user communication and remote access to a LAN. They may have a mixture of analog and + digital (ISDN) interfaces and support hundreds of simultaneous users.

+ + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Crossword Puzzle: WAN Devices and Interfaces

+

Upon completing this activity, the student + will be able to describe devices and interfaces associated with + WAN connections.

+ +

+
+
+ + +     + + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

WAN

+ + http://www.cisco.com/en/US/tech/tk713/ + tech_topology_and_network_ serv_and_protocol_suite_ home.html

+ +

+

+
+
+

+       +    + + + +

+ + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/media.html new file mode 100644 index 0000000..19651e5 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_2/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/buttons.html new file mode 100644 index 0000000..acddf46 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/buttons.html @@ -0,0 +1,109 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/content.html new file mode 100644 index 0000000..3ebd593 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/content.html @@ -0,0 +1,156 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.1 + WAN Technologies Overview 
  + 2.1.3 + WAN standards 
+ + + + + + +
+ + WANs use the OSI reference model, but focus + mainly on Layer 1 and Layer 2. WAN standards typically + describe both physical layer delivery methods and data link layer + requirements, including physical addressing, flow control, and encapsulation. + WAN standards are defined and managed by a number of recognized + authorities. +

+ The physical layer protocols describe how + to provide electrical, mechanical, operational, and functional + connections to the services provided by a communications service + provider. Some of the common physical layer standards are listed in + Figure + , and their + connectors illustrated in Figure + .

+

The data link layer protocols define how + data is encapsulated for transmission to remote sites, and the + mechanisms for transferring the resulting frames. A variety of + different technologies are used, such as ISDN, Frame Relay or + Asynchronous Transfer Mode (ATM). These + protocols use the same basic framing mechanism, high-level data link + control (HDLC), an ISO standard, or one of its sub-sets or variants. +

+ + + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Crossword Puzzle: + WAN Standards

+

+ Upon completing this activity, the student + will be able to identify various WAN standards.

+ +

+
+
+ + +     + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

WAN

+ + http://www.cisco.com/en/US/tech/tk713/ + tech_topology_and_network_ serv_and_protocol_suite_ home.html

+ +

+

+
+
+

+       +   +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/media.html new file mode 100644 index 0000000..62e453f --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_3/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/buttons.html new file mode 100644 index 0000000..c81be64 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/content.html new file mode 100644 index 0000000..74c7c6a --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/content.html @@ -0,0 +1,138 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.1 + WAN Technologies Overview 
  + 2.1.4 + WAN encapsulation 
+ + + + + + +
+ + + Data from the network layer is passed to the data link layer for + delivery on a physical link, which is normally point-to-point on a WAN + connection. The data link layer builds a + frame around the network layer data so the necessary checks and + controls can be applied. Each WAN connection type uses a Layer 2 + protocol to encapsulate traffic while it is crossing the WAN link. To + ensure that the correct encapsulation protocol is used, the Layer 2 + encapsulation type used for each router serial interface must be + configured. The choice of encapsulation protocols depends on the WAN + technology and the equipment. Most framing is based on the HDLC + standard.

HDLC framing gives reliable delivery of data over + unreliable lines and includes signal mechanisms for flow and error + control. + The frame + always starts and ends with an 8-bit flag field, the bit pattern + 01111110. Because there is a likelihood that this + pattern will occur in the actual data, the sending HDLC system always + inserts a 0 bit after every five 1s in the data field, so in practice + the flag sequence can only occur at the frame ends. The receiving + system strips out the inserted bits. When frames are transmitted + consecutively the end flag of the first frame is used as the start + flag of the next frame.

+

The address field is not needed for WAN links, which are almost + always point-to-point. The address field is still present and + may be one or two bytes long. The control field indicates the frame + type, which may be information, supervisory, or unnumbered:

+
    +
  • Unnumbered frames carry line setup messages.
    • +
  • Information frames carry network layer data.
    • +
  • Supervisory frames control the flow of information frames and + request data retransmission in the event of an error.
    • +
+

The control field is normally one byte, but will be two bytes for + extended sliding windows systems. Together the address and control + fields are called the frame header. The encapsulated data follows the + control field. Then a frame check sequence (FCS) uses the + cyclic redundancy check (CRC) mechanism to establish a two or four + byte field.

+

Several data link protocols are used, including sub-sets and + proprietary versions of HDLC. + Both PPP + and the Cisco version of HDLC have an extra field in the header to identify the network layer protocol of the encapsulated + data. +

+

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

WAN

+ + http://www.cisco.com/en/US/tech/tk713/ + tech_topology_and_ network_serv_and_ + protocol_suite_ home.html

+ +

+

+
+
+

+       +      + + +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/media.html new file mode 100644 index 0000000..2c823c9 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_4/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/buttons.html new file mode 100644 index 0000000..036b842 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/content.html new file mode 100644 index 0000000..d79bb1b --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/content.html @@ -0,0 +1,157 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.1 + WAN Technologies Overview 
  + 2.1.5 + Packet and circuit switching +  
+ + + + + + +
+ + + Packet-switched networks were developed to overcome the expense of + public circuit-switched networks and to provide a more cost-effective + WAN technology.

When a subscriber makes a telephone call, the dialed + number is used to set switches in the exchanges along the route of the + call so that there is a continuous circuit from the originating caller + to that of the called party. Because of the switching operation + used to establish the circuit, the telephone system is called a + circuit-switched network. If the telephones are replaced with modems, + then the switched circuit is able to carry computer data. +

+

The internal path taken by the circuit between exchanges is shared + by a number of conversations. Time division multiplexing (TDM) is + used to give each conversation a share of the connection in turn. TDM + assures that a fixed capacity connection is made available to the + subscriber.

+

If the circuit carries computer data, the usage of this + fixed capacity may not be efficient. For example, if the circuit is + used to access the Internet, there will be a burst of activity on the + circuit while a web page is transferred. This could be followed by no + activity while the user reads the page and then another burst of + activity while the next page is transferred. This variation in usage + between none and maximum is typical of computer network traffic. + Because the subscriber has sole use of the fixed capacity allocation, + switched circuits are generally an expensive way of moving data.

+

An alternative is to allocate the capacity to the traffic only when + it is needed, and share the available capacity between many users. + With a circuit-switched connection, the data bits put on the circuit + are automatically delivered to the far end because the circuit is + already established. If the circuit is to be shared, there must be + some mechanism to label the bits so that the system knows where to + deliver them. It is difficult to label individual bits, therefore they + are gathered into groups called cells, frames, or packets. + The packet passes from exchange to exchange for delivery through the + provider network. Networks that implement + this system are called packet-switched networks. +

+

The links that connect the switches in the provider network belong + to an individual subscriber during data transfer, therefore many + subscribers can share the link. Costs can be significantly lower + than a dedicated circuit-switched connection. Data on packet-switched + networks are subject to unpredictable delays when individual packets + wait for other subscriber packets to be transmitted by a switch.

+

The switches in a packet-switched network determine, from + addressing information in each packet, which link the packet must be + sent on next. There are two approaches to this link + determination, connectionless or connection-oriented. Connectionless + systems, such as the Internet, carry full addressing information in + each packet. Each switch must evaluate the address to + determine where to send the packet. Connection-oriented systems + predetermine the route for a packet, and each packet need only carry + an identifier. In the case of Frame Relay, these are called Data Link + Control Identifiers (DLCI). The switch determines the onward route by + looking up the identifier in tables held in memory. The set of entries + in the tables identifies a particular route or circuit through the + system. If this circuit is only physically in existence while a packet + is traveling through it, it is called a Virtual Circuit (VC).

+

The table entries that constitute a VC can be established by + sending a connection request through the network. In this case the + resulting circuit is called a Switched Virtual Circuit (SVC). Data + that is to travel on SVCs must wait until the table entries have been + set up. Once established, the SVC may be in operation for hours, days + or weeks. Where a circuit is required to be always available, a + Permanent Virtual Circuit (PVC) will be established. Table entries are + loaded by the switches at boot time so the PVC is always available.

+

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

Packet vs Circuit Switching

+ + http://www.cina.org/ac051599/sld011.htm

+ +

+

+
+
+

+       +       + + +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/media.html new file mode 100644 index 0000000..24ccdd5 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_5/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/buttons.html new file mode 100644 index 0000000..2d87190 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/content.html new file mode 100644 index 0000000..b6c42c7 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/content.html @@ -0,0 +1,147 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.1 + WAN Technologies Overview 
  + 2.1.6 + WAN link options 
+ + + + + + +
+ + + Figure + provides an overview of WAN link options. +

Circuit switching establishes a dedicated physical connection for voice + or data between a sender and receiver. Before communication can start, it + is necessary to establish the connection by setting the switches. This + is done by the telephone system, using the dialed number. ISDN is used + on digital lines as well as on voice-grade lines. If the local loop is + not directly connected to the telephone system, a digital subscriber + line (DSL) may be available.

+

To avoid the delays associated with setting up a connection, + telephone service providers also offer permanent circuits. These + dedicated or leased lines offer higher bandwidth than is available + with a switched circuit. Examples of circuit-switched connections + include:

+
    +
  • Plain Old Telephone System (POTS)
    • +
  • ISDN Basic Rate Interface (BRI)
    • +
  • ISDN Primary Rate Interface (PRI)
    • +
+

Many WAN users do not make efficient use of the fixed bandwidth + that is available with dedicated, switched, or permanent circuits, because the data flow + fluctuates. Communications providers have data networks available to + more appropriately service these users. In these networks, the data is transmitted in labeled + cells, frames, or packets through a packet-switched network. Because + the internal links between the switches are shared between many users, + the costs of packet switching are lower than those of circuit + switching. Delays (latency) and variability of delay (jitter) are + greater in packet-switched than in circuit-switched networks. This is + because the links are shared and packets must be entirely received at + one switch before moving to the next. Despite the latency and jitter + inherent in shared networks, modern technology allows satisfactory + transport of voice and even video communications on these networks.

+

Packet-switched networks may establish routes through the switches + for particular end-to-end connections. Routes established when the + switches are started are PVCs. Routes established on demand are SVCs. If the routing is not + pre-established and is worked out by each switch for each packet, the + network is called connectionless.

+

To connect to a packet-switched network, a subscriber needs a local + loop to the nearest location where the provider makes the service + available. This is called the point-of-presence (POP) of the service. + Normally this will be a dedicated leased line. This line will be much + shorter than a leased line directly connected to + the subscriber locations, and often carries several VCs. + Since it + is likely that not all the VCs will require maximum demand + simultaneously, the capacity of the leased line can be smaller than + the sum of the individual VCs. Examples of packet or cell switched + connections include:

+
    +
  • Frame Relay
    • +
  • X.25
    • +
  • ATM
    • +
+

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

WAN

+ + http://www.cisco.com/en/US/tech/ tk713/ + tech_topology_and_ network_serv_and_ + protocol_suite_ home.html

+ +

+

+
+
+

+       +      + + +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/media.html new file mode 100644 index 0000000..8677acd --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_1_6/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/buttons.html new file mode 100644 index 0000000..f8bfdd3 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/content.html new file mode 100644 index 0000000..0ddfff9 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/content.html @@ -0,0 +1,176 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.2 + WAN Technologies 
  + 2.2.1 + Analog dialup 
+ + + + + + +
+ + + When intermittent, low-volume data transfers are needed, modems and + analog dialed telephone lines provide low capacity and dedicated + switched connections. +

+ + + Traditional telephony uses a copper cable, called the local loop, to + connect the telephone handset in the subscriber premises to the public + switched telephone network (PSTN). The signal on the local loop during + a call is a continuously varying electronic signal that is a + translation of the subscriber voice.

+

+ + + The local loop is not suitable for direct transport of binary computer + data, but a modem can send computer data through the voice telephone + network. The modem modulates the binary data into an analog signal at + the source and demodulates the analog signal at the destination to + binary data.

+

+ + The physical characteristics of the local + loop and its connection to the PSTN limit the rate of the signal. The upper limit is + around 33 kbps. The rate can be increased to around 56 kbps if the + signal is coming directly through a digital connection.

+

+ + + For small businesses, this can be adequate for the exchange of sales + figures, prices, routine reports, and email. Using automatic dialup at + night or on weekends for large file transfers and data backup can take + advantage of lower off-peak tariffs (line charges). Tariffs are based + on the distance between the endpoints, time of day, and the duration + of the call.

+

+ + + The advantages of modem and analog lines are simplicity, availability, + and low implementation cost. The disadvantages are the low data rates + and a relatively long connection time. The dedicated circuit provided + by dialup will have little delay or jitter for point-to-point + traffic, but voice or video traffic will not operate adequately at + relatively low bit rates.

+

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Checkbox: WAN Technologies Analog Dialup

+

Upon completing this activity, the student + will be able to identify the characteristics associated with an + analog dialup circuit.

+ +

+
+
+ + +     + + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

Dialup Technologies

+ + http://www.cisco.com/univercd/cc/ + td/doc/cisintwk/ito_doc/ dialup.htm

+ +

+

+
+
+

+       +         +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/media.html new file mode 100644 index 0000000..24058ab --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_1/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/buttons.html new file mode 100644 index 0000000..d95c9af --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/content.html new file mode 100644 index 0000000..2aab77a --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/content.html @@ -0,0 +1,181 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + + +
+ + 2.2 + WAN Technologies 
  + 2.2.2 + ISDN +  
+ + + + + + +
+ + The internal connections, or trunks, of + the PSTN have changed from carrying analog frequency-division + multiplexed signals, to time-division multiplexed (TDM) digital + signals. An obvious next step + is to enable the local loop to carry digital signals that result in + higher capacity switched connections. +

Integrated Services Digital Network (ISDN) turns the local loop into a + TDM digital connection. The connection uses 64 kbps bearer channels + (B) for carrying voice or data and a signaling, delta channel (D) for + call set-up and other purposes. +

Basic Rate Interface (BRI) ISDN is intended for the home and small + enterprise and provides two 64 kbps B channels and a 16 kbps D + channel. For larger installations, Primary Rate Interface (PRI) ISDN + is available. PRI delivers twenty-three 64 kbps B channels and one 64 + kbps D + channel in North America, for a total bit rate of up to 1.544 Mbps. + This includes some additional overhead for synchronization. In Europe, + Australia, and other parts of the world, ISDN PRI provides thirty B + channels and one D channel for a total bit rate of up to 2.048 Mbps, + including synchronization overhead. + In North + America PRI corresponds to a T1 connection. The rate of international + PRI corresponds to an E1 connection.

The BRI D channel is + underutilized, as it has only two B channels to control. Some + providers allow the D channel to carry data at low bit rates such as + X.25 connections at 9.6 kbps.

For small WANs, the BRI ISDN can provide an ideal connection + mechanism. BRI has a call setup time that is less than a second, and + its 64 kbps B channel provide greater capacity than an analog modem + link. + If greater capacity is required, a second + B channel can be + activated to provide a total of 128 kbps. Although inadequate for video, this + would permit several simultaneous voice conversations in addition to + data traffic.

Another common application of ISDN is to provide additional capacity + as needed on a leased line connection. The leased line is sized to + carry average traffic loads while ISDN is added during peak demand + periods. ISDN is also used as a backup in the case of a failure of the + leased line. ISDN tariffs are based on a per-B channel basis and are + similar to those of analog voice connections.

With PRI ISDN, multiple B channels can be connected between two end + points. This allows for video conferencing and high bandwidth data + connections with no latency or jitter. Multiple connections can become + very expensive over long distances.

+ + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Checkbox: WAN Technologies ISDN Dialup

+

Upon completing this activity, the student + will be able to identify the characteristics associated with an + ISDN dialup circuit.

+ +

+
+
+ + +     + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

Integrated Services Digital Network (ISDN)

+ + http://www.cisco.com/univercd/cc/td/doc/ cisintwk/ito_doc/isdn.htm

+ +

+

+
+
+

+       +   

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/media.html new file mode 100644 index 0000000..7a8880d --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_2/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/buttons.html new file mode 100644 index 0000000..03c01c5 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/content.html new file mode 100644 index 0000000..2720a39 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/content.html @@ -0,0 +1,132 @@ + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.2 + WAN Technologies 
  + 2.2.3 + Leased line 
+ + + + + + +
+ + When permanent dedicated connections are + required, leased lines are used with capacities ranging up to 2.5 Gbps.

+ A point-to-point link provides a + pre-established WAN communications path from the customer premises + through the provider network to a remote destination. Point-to-point + lines are usually leased from a carrier and are called leased lines. + Leased lines are available in different capacities. + These + dedicated circuits are generally priced based on bandwidth required + and distance between the two connected points. Point-to-point links + are generally more expensive than shared services such as Frame Relay. + The cost of leased-line solutions can become significant when they are + used to connect many sites. There are times when cost of the leased + line is outweighed by the benefits. The dedicated capacity gives no + latency or jitter between the endpoints. Constant availability is + essential for some applications such as electronic commerce.

+

A router serial port is required for + each leased-line connection. A CSU/DSU and the actual circuit from the service provider are also + required.

+

Leased lines are used extensively for + building WANs and give permanent dedicated capacity. + They have + been the traditional connection of choice but have a number of + disadvantages. WAN traffic is often variable and leased lines have a + fixed capacity. This results in the bandwidth of the line seldom being + exactly what is needed. In addition, each end point would need an + interface on the router which would increase equipment costs. Any changes to the leased line + generally require a site visit by the carrier to change capacity.

+

Leased lines + provide direct point-to-point connections between enterprise LANs and connect individual branches to a + packet-switched network. Several connections can be multiplexed over + a leased line, resulting in shorter links and fewer required + interfaces.

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Checkbox: WAN Technologies Leased Lines

+

Upon completing this activity, the student + will be able to identify the characteristics associated with a + leased line connection.

+ +

+
+
+ + +     + + + +
+ + + + + + +

  

+ + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/media.html new file mode 100644 index 0000000..c0bbbbe --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_3/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/buttons.html new file mode 100644 index 0000000..a43981f --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/content.html new file mode 100644 index 0000000..4ed41d2 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/content.html @@ -0,0 +1,165 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.2 + WAN Technologies 
  + 2.2.4 + X.25 
+ + + + + + + +
+ In response to the expense of leased + lines, telecommunications providers introduced packet-switched + networks using shared lines to reduce costs. The first of these + packet-switched networks was standardized as the X.25 group of + protocols. X.25 provides a low bit rate shared variable capacity that + may be either switched or permanent. +

+ X.25 is a network-layer protocol and + subscribers are provided with a network address. Virtual circuits can + be established through the network with call request packets to the + target address. The resulting SVC is + identified by a channel number. Data packets labeled with the channel + number are delivered to the corresponding address. Multiple channels + can be active on a single connection.

+

Subscribers connect to the X.25 network + with either leased lines or dialup connections. X.25 networks can also + have pre-established channels between subscribers that provide a + + PVC.

+

X.25 can be very cost effective because + tariffs are based on the amount of data delivered rather than + connection time or distance. Data can be delivered at any rate up to + the connection capacity. This provides some flexibility. X.25 networks + are usually low capacity, with a maximum of 48 kbps. In addition, the + data packets are subject to the delays typical of shared networks.

+

X.25 technology is no longer widely + available as a WAN technology in the US. Frame Relay has replaced X.25 at many service provider locations.

+

Typical X.25 applications are + point-of-sale card readers. These readers use X.25 in dialup mode to + validate transactions on a central computer. Some enterprises also use + X.25 based value-added networks (VAN) to transfer Electronic Data + Interchange (EDI) invoices, bills of lading, and other commercial + documents. For these applications, the low bandwidth and high latency + are not a concern, because the low cost makes the use of X.25 + affordable.

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Checkbox: WAN Technologies X.25

+

Upon completing this activity, the student + will be able to identify the characteristics associated with an + X.25 connection.

+ +

+
+
+ + +     + + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

X.25 Protocol

+ + http://www2.rad.com/networks/1996/ x25/x25.htm

+ +

+

+
+
+

+       +     +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/media.html new file mode 100644 index 0000000..e8665cd --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_4/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/buttons.html new file mode 100644 index 0000000..f41ac31 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/content.html new file mode 100644 index 0000000..54c608f --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/content.html @@ -0,0 +1,160 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.2 + WAN Technologies 
  + 2.2.5 + Frame Relay 
+ + + + + + + +
+ With increasing demand for higher + bandwidth and lower latency packet switching, communications providers + introduced Frame Relay. Although the network layout appears + similar to that for X.25, available data rates are commonly up to 4 + Mbps, with some providers offering even higher rates. +

+ Frame Relay differs from X.25 in several + aspects. Most importantly, it is a much simpler protocol that works at + the data link layer rather than the network layer.

+

Frame Relay implements no error or flow + control. The simplified handling of frames leads to reduced latency, + and measures taken to avoid frame build-up at intermediate switches + help reduce jitter.

+

Most Frame Relay connections are PVCs rather than SVCs. The connection to the network edge is often + a leased line but dialup connections are available from some providers + using ISDN lines. The ISDN D channel is used to set up an SVC on one + or more B channels. Frame Relay tariffs are based on the capacity of + the connecting port at the network edge. Additional factors are the + agreed capacity and + committed information rate (CIR) of the various PVCs through the + port. +

+

Frame Relay provides permanent shared + medium bandwidth connectivity that carries both voice and data + traffic. Frame Relay is ideal for connecting enterprise LANs. The + router on the LAN needs only a single interface, even when multiple + VCs are used. The short-leased line to the FR network edge allows + cost-effective connections between widely scattered LANs.

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Checkbox: WAN Technologies Frame Relay

+

Upon completing this activity, the student + will be able to identify the characteristics associated with a + Frame Relay circuit.

+ +

+
+
+ + +     + + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

Frame Relay

+ + http://www.cisco.com/univercd/cc/ + td/doc/cisintwk/ito_doc/frame.htm

+ +

+

+
+
+

+       + +       +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/media.html new file mode 100644 index 0000000..2d15f2d --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_5/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/buttons.html new file mode 100644 index 0000000..6d990cf --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/content.html new file mode 100644 index 0000000..78e67ba --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/content.html @@ -0,0 +1,161 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.2 + WAN Technologies 
  + 2.2.6 + ATM 
+ + + + + + + +
+ Communications providers saw a need for a permanent shared + network technology that offered very low latency and jitter at much + higher bandwidths. Their solution + was Asynchronous Transfer Mode (ATM). ATM has data rates beyond 155 + Mbps. As with the other shared technologies, such as X.25 and Frame + Relay, diagrams for ATM WANs look the same. 

+ ATM is a technology that is capable of + transferring voice, video, and data through private and public + networks. It is built on a cell-based architecture rather than on a + frame-based architecture. ATM cells are always a fixed length of 53 + bytes. The 53 byte ATM cell contains a 5 byte ATM header followed by + 48 bytes of ATM payload. Small, fixed-length cells are well suited for + carrying voice and video traffic because this traffic is intolerant of + delay. Video and voice traffic do not have to wait for a larger data + packet to be transmitted.

+

+ The 53 byte ATM cell is less efficient + than the bigger frames and packets of Frame Relay and X.25. + Furthermore, the ATM cell has at least 5 bytes of overhead for each + 48-byte payload. When the cell is carrying segmented network layer + packets, the overhead will be higher because the ATM switch must be + able to reassemble the packets at the destination. A typical ATM line + needs almost 20% greater bandwidth than Frame Relay to carry the same + volume of network layer data.

+

+ ATM offers both PVCs and SVCs, although + PVCs are more common with WANs.

+

+ As with other shared technologies, ATM + allows multiple virtual circuits on a single leased line connection to + the network edge.

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Checkbox: WAN Technologies Asynchronous Transfer Mode (ATM)

+

Upon completing this activity, the student + will be able to identify the characteristics associated with ATM + connections.

+ +

+
+
+ + +     + + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

Asynchronous Transfer Mode (ATM) Switching

+ + http://www.cisco.com/univercd/cc/ + td/doc/cisintwk/ito_doc/atm.htm

+ +

+

+
+
+

+       +       +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/media.html new file mode 100644 index 0000000..8167afe --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_6/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/buttons.html new file mode 100644 index 0000000..287aab0 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/content.html new file mode 100644 index 0000000..04e5270 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/content.html @@ -0,0 +1,152 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.2 + WAN Technologies 
  + 2.2.7 + DSL 
+ + + + + + + +
+ Digital Subscriber Line (DSL) technology + is a broadband technology that uses existing twisted-pair telephone + lines to transport high-bandwidth data to service subscribers. DSL + service is considered broadband, as opposed to the baseband service + for typical LANs. Broadband refers to a technique which uses multiple + frequencies within the same physical medium to transmit data. The term + xDSL covers a number of similar yet competing forms of DSL + technologies: +
    +
  • Asymmetric DSL (ADSL)
    • +
  • Symmetric DSL (SDSL)
    • +
  • High Bit Rate DSL (HDSL)
    • +
  • ISDN (like) DSL (IDSL)
    • +
  • Rate Adaptive DSL (RADSL)
    • +
  • Consumer DSL (CDSL), also called + DSL-lite or G.lite
    • +
+

+ DSL technology + allows the service provider to offer high-speed network services to + customers, utilizing installed local loop copper lines. DSL + technology allows the local loop line to be used for normal + telephone voice connection and an always-on + connection for instant network connectivity. Multiple + DSL subscriber lines are multiplexed into a single, high capacity link + by the use of a DSL Access Multiplexer (DSLAM) at the provider + location. DSLAMs incorporate TDM + technology to aggregate many subscriber lines into a less cumbersome + single medium, generally a T3/DS3 connection. Current DSL technologies + are using sophisticated coding and modulation techniques to achieve + data rates up to 8.192 Mbps.

+

The voice channel of a standard + consumer telephone covers the frequency range of 330 Hz to 3.3 KHz. A + frequency range, or window, of 4 KHz is regarded as the requirements + for any voice transmission on the local loop. DSL technologies place + upload (upstream) and download (downstream) data transmissions at + frequencies above this 4 KHz window. This technique is what allows + both voice and data transmissions to occur simultaneously on a DSL + service. +

+

The two basic types of DSL technologies + are asymmetric (ADSL) and symmetric (SDSL). All forms of DSL service + are categorized as ADSL or SDSL and there are several varieties of + each type. Asymmetric service provides + higher download or downstream bandwidth to the user than upload + bandwidth. Symmetric service provides the same capacity in both + directions.

+

The different varieties of DSL provide + different bandwidths, with capabilities exceeding those of a T1 or E1 + leased line. The transfer rates are dependent on the actual length of + the local loop and the type and condition of its cabling. For + satisfactory service, the loop must be less than 5.5 kilometers (3.5 + miles). DSL availability is far from universal, and there are a wide + variety of types, standards, and emerging standards. It is not a + popular choice for enterprise computer departments to support home + workers. Generally, a subscriber cannot choose to connect to the + enterprise network directly, but must first connect to an Internet + service provider (ISP). From + here, an IP connection is made through the Internet to the enterprise. + Thus, security risks are incurred. To address security concerns, DSL + services provide capabilities for using Virtual Private Network (VPN) + connections to a VPN server, which is typically located at the + corporate site.

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Checkbox: WAN Technologies Digital Subscriber Line (DSL)

+

Upon completing this activity, the student + will be able to identify the characteristics associated with DSL + connections.

+ +

+
+
+ + +

    + +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/media.html new file mode 100644 index 0000000..5272b3c --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_7/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/buttons.html new file mode 100644 index 0000000..884ce62 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/content.html new file mode 100644 index 0000000..8e11a56 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/content.html @@ -0,0 +1,126 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.2 + WAN Technologies 
  + 2.2.8 + Cable modem 
+ + + + + + + +
+ Coaxial cable is + widely used in urban areas to distribute television signals. + Network + access is available from some cable television networks. This allows + for greater bandwidth than the conventional telephone local loop. + +

Enhanced cable modems enable two-way, + high-speed data transmissions using the same coaxial lines that + transmit cable television. Some cable service providers are promising data speeds up + to 6.5 times that of T1 leased lines. This speed makes cable an + attractive medium for transferring large amounts of digital + information quickly, including video clips, audio files, and large + amounts of data. Information that would take two minutes to download + using ISDN BRI can be downloaded in two seconds through a cable modem + connection.

+

Cable modems provide an always-on + connection and a simple installation. An always-on cable + connection means that connected computers are vulnerable to a security + breach at + all times and need to be suitably secured with firewalls. To address + security concerns, cable modem services provide capabilities for using + Virtual Private Network (VPN) connections to a VPN server, which is + typically located at the corporate site.

+

A cable modem is capable of delivering + up to 30 to 40 Mbps of data on one 6 MHz cable channel. This is almost + 500 times faster than a 56 Kbps modem.

+

With a cable modem, a subscriber can + continue to receive cable television service while simultaneously + receiving data to a personal computer. This is + accomplished with the help of a simple one-to-two splitter. +

+

Cable modem subscribers must use the + ISP associated with the service provider. All the local subscribers + share the same cable bandwidth. As more users join the service, available + bandwidth may be below the expected rate. + + - +

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Checkbox: WAN Technologies Cable Modems

+

Upon completing this activity, the student + will be able to identify the characteristics associated with + cable modems.

+ +

+
+
+ + +

    +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/media.html new file mode 100644 index 0000000..1625c7e --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_2_8/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/buttons.html new file mode 100644 index 0000000..6c5273b --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/content.html new file mode 100644 index 0000000..06ab9f1 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/content.html @@ -0,0 +1,130 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.3 + WAN Design 
  + 2.3.1 + WAN communication 
+ + + + + + +
WANS are considered to be a set of data + links connecting routers on LANs. User end stations and servers on LANs + exchange data. Routers pass data between networks across the + data links.

Because of cost and + legal reasons, a communications provider or a common carrier normally + owns the data links that make up a WAN. The links are made available to + subscribers for a fee and are used to interconnect LANs or connect to + remote networks. WAN data transfer speed (bandwidth) is considerably + slower than the 100 Mbps that is common on a LAN. The charges for link provision are + the major cost element of a WAN and the design must aim to provide + maximum bandwidth at acceptable cost. With user pressure to provide more + service access at higher speeds and management pressure to contain cost, + determining the optimal WAN configuration is not an easy task.

+

WANs carry a variety of traffic types + such as data, voice, and video. The design selected must provide + adequate capacity and transit times to meet the requirements of the + enterprise. Among other specifications, the design must consider the + topology of the connections between the various sites, the nature of + those connections, and bandwidth capacity. +

+

Older WANs often consisted of data links + directly connecting remote mainframe computers. + Today’s + WANs, though, connect geographically separated LANs. + End-user + stations, servers, and routers communicate across LANs, and the WAN data + links terminate at local routers. By exchanging Layer 3 address + information about directly connected LANs, routers determine the most + appropriate path through the network for the required data streams. + Routers can also provide quality of service (QoS) management, which + allots priorities to the different traffic streams. + +

+

Because the WAN is merely a set of + interconnections between LAN based routers, there are no services on the + WAN. WAN technologies function at the lower three layers of the OSI + reference model. + Routers + determine the destination of the data from the network layer headers and + transfer the packets to the appropriate data link connection for + delivery on the physical connection.

+

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + Web Links

+ + +

Introduction to WAN Technologies

+ + http://www.cisco.com/univercd/cc/
+ + td/doc/cisintwk/ito_doc/introwan.htm

+ +

+

+
+
+

+       +     +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/media.html new file mode 100644 index 0000000..a5865ba --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_1/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/buttons.html new file mode 100644 index 0000000..ef37094 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/content.html new file mode 100644 index 0000000..8a030d2 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/content.html @@ -0,0 +1,129 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.3 + WAN Design 
  + 2.3.2 + Steps in WAN design 
+ + + + + + +
+

Designing a WAN can be a challenging task, but + approaching the design in a systematic manner can lead to superior + performance at a reduced cost. Many WANs have evolved over time, + therefore many of the guidelines discussed here may not have been + considered. Every time a modification to an existing WAN is + considered, the steps in this module should be followed. WAN + modifications may arise from changes such as an expansion in the + enterprise the WAN serves, or accommodation of new work practices and + business methods.

+

Enterprises install WAN connectivity + because there is a need to move data in a timely manner between + external branches. The WAN is there to support the enterprise + requirements. Meeting these requirements incurs costs, such as + equipment provisioning and management of the data links.

+

In designing the WAN, it is necessary to know what data traffic must + be carried, its origin, and its destination. WANs carry a variety of + traffic types with varying requirements for bandwidth, latency, and + jitter.

+

For each pair of end points and for each traffic type, information is + needed on the various traffic characteristics. + Determining this may + involve extensive studies of and consultation with the network users. + The design often involves upgrading, extending, or modifying an + existing WAN. Much of the data needed can come from existing network + management statistics.

+

Knowing the various end points allows the selection of a topology or + layout for the WAN. The topology will be influenced by geographic + considerations but also by requirements such as availability. A high + requirement for availability will require extra links that provide + alternative data paths for redundancy and load balancing.

+

With the end points and the links chosen, the necessary bandwidth can + be estimated. Traffic on the links may have varying requirements for + latency and jitter. With the bandwidth availability already + determined, suitable link technologies must be selected.

+

Finally, installation and operational costs for the WAN can be + determined and compared with the business need driving the WAN + provision.

+

In practice, following the steps shown in + Figure is seldom a linear + process. Several modifications may be necessary before a design is + finalized. Continued monitoring and re-evaluation are also required + after installation of the WAN to maintain optimal performance.

+ + + + +
+ + + + + +
+ +
+ + + + + +
+ + + + + +
  +

+ + + Interactive Media Activity

+ +

Drag and Drop: WAN Design Steps

+

When the student has completed this activity, the student + will be able to identify the basic steps in designing a WAN.

+ +

+
+
+ + +

    + +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/media.html new file mode 100644 index 0000000..9e14bd6 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_2/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/buttons.html new file mode 100644 index 0000000..4b75757 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
  + + + + + + + +
+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/content.html new file mode 100644 index 0000000..d06aba9 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/content.html @@ -0,0 +1,115 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.3 + WAN Design 
  + 2.3.3 + How to + identify and select networking capabilities 
+ + + + + + +
Designing a WAN essentially consists of + the following:
    +
  • Selecting an interconnection pattern + or layout for the links between the various locations
    • +
  • Selecting the technologies for those + links to meet the enterprise requirements at an acceptable cost
    • +
+

Many WANs use a star topology. As the + enterprise grows and new branches are added, the branches are connected + back to the head office, producing a traditional star topology. + Star + end-points are sometimes cross-connected, creating a mesh or partial + mesh topology. + This + provides for many possible combinations for interconnections. When + designing, re-evaluating, or modifying a WAN, a + topology that meets the design requirements must be selected. +

+

In selecting a layout, there are several + factors to consider. More links will increase the cost of the network + services, and having multiple paths between destinations increases + reliability. Adding more network devices to the data path will increase + latency and decrease reliability. Generally, each packet must be completely received at one + node before it can be passed to the next. A range of dedicated + technologies with different features is available for the data links. +

+

Technologies that require the establishment of a connection before data + can be transmitted, such as basic telephone, ISDN, or X.25, are not + suitable for WANs that require rapid response time or low latency. Once + established, ISDN and other dialup services are low latency, low jitter + circuits. ISDN is often the application of choice for connecting a small + office or home office (SOHO) network to the enterprise network, + providing reliable connectivity and adaptable bandwidth. Unlike cable + and DSL, ISDN is an option wherever modern telephone service is + available. ISDN is also useful as a backup link for primary connections + and for providing bandwidth-on-demand connections in parallel with a + primary connection. A feature of these technologies is that the + enterprise is only charged a fee when the circuit is in use.

+

The different parts of the enterprise may + be directly connected with leased lines, or they may be connected with + an access link to the nearest point-of-presence (POP) of a shared + network. X.25, Frame Relay, and ATM are examples of shared networks. + Leased lines will generally be much longer and therefore more expensive + than access links, but are available at virtually any bandwidth. They + provide very low latency and jitter.

+

ATM, Frame Relay, and X.25 networks carry + traffic from several customers over the same internal links. The + enterprise has no control over the number of links or hops that data + must traverse in the shared network. It cannot control the time data + must wait at each node before moving to the next link. This uncertainty + in latency and jitter makes these technologies unsuitable for some types + of network traffic. However, the disadvantages of a shared network may + often be outweighed by the reduced cost. Because several customers are + sharing the link, the cost to each will generally be less than the cost + of a direct link of the same capacity.

+

Although ATM is a shared network, it has + been designed to produce minimal latency and jitter through the use of + high-speed internal links sending easily manageable units of data, + called cells. ATM cells have a fixed length of 53 bytes, 48 for data and + 5 for the header. ATM is widely used + for carrying delay-sensitive traffic. Frame Relay may also be used for + delay-sensitive traffic, often using QoS mechanisms to give priority to + the more sensitive data.

+

A typical WAN uses a combination of technologies that are usually chosen + based on traffic type and volume.  ISDN, DSL, Frame Relay, or + leased lines are used to connect individual branches into an area. Frame Relay, ATM, or + leased lines are used to connect external areas back to the backbone. + ATM or leased lines form the WAN backbone.

+

       +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/media.html new file mode 100644 index 0000000..ea223d1 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_3/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_4/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_4/buttons.html new file mode 100644 index 0000000..23a8321 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_4/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
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+ + 2.3 + WAN Design 
  + 2.3.4 + Three-layer design model 
+ + + + + + +
+ A systematic approach is needed when many locations + must be joined. A hierarchical solution with three layers offers many + advantages. + +

Imagine an enterprise that is operational in every country of the + European Union and has a branch in every town with a population over + 10,000. Each branch has a LAN, and it has been decided to interconnect + the branches. A mesh network is clearly not feasible because nearly + 500,000 links would be needed for the 900 centers. A simple + star will be very difficult to implement because it needs a router + with 900 interfaces at the hub or a single interface that carries 900 + virtual circuits to a packet-switched network.

+

Instead, consider a hierarchical design model. A group of LANs in an + area are interconnected, several areas are interconnected to form a + region, and the various regions are interconnected to form the core of + the WAN.

+

The area could be based on the number of locations to be connected + with an upper limit of between 30 and 50. The area would have a star + topology, + + with the hubs of the stars linked to form the region. + + + Regions could be geographic, connecting between three and ten areas, + and the hub of each region could be linked point-to-point. +

+

This three-layer model follows the hierarchical design used in telephone + systems. The links connecting the various sites in an area that + provide access to the enterprise network are called the access links + or access layer of the WAN. Traffic between areas is distributed by + the distribution links, and is moved onto the core links for transfer + to other regions, when necessary.

+

This hierarchy is often useful when the network traffic mirrors the + enterprise branch structure and is divided into regions, areas, and + branches. It is also useful when there is a central service to which + all branches must have access, but traffic levels are insufficient to + justify direct connection of a branch to the service.

+

The LAN at the center of the area may have servers providing + area-based as well as local service. Depending on the traffic volumes + and types, the access connections may be dial up, leased, or Frame + Relay. Frame Relay facilitates some meshing for redundancy without + requiring additional physical connections. Distribution links could be + Frame Relay or ATM, and the network core could be ATM or leased line.

+

+ +      

+
+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_4/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_4/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_4/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_4/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_4/media.html new file mode 100644 index 0000000..6db7cf3 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_4/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_5/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_5/buttons.html new file mode 100644 index 0000000..1485ee2 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_5/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
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+ + 2.3 + WAN Design 
  + 2.3.5 + Other layered design models 
+ + + + + + +
+ Many networks do not require the complexity of a + full three-layer hierarchy. + Simpler hierarchies may be used. +

+ An enterprise with several relatively small branches that require + minimal inter-branch traffic may choose a one-layer design. Historically + this has not been popular because of the length of the leased lines. + Frame Relay, where charges are not distance related, is now making this + a feasible design solution.

+

+ If there is a need for some geographical concentration, a two-level + design is appropriate. This produces a “star of stars” pattern. Again, + the pattern chosen based on leased line technology will be + considerably different from the pattern based on Frame Relay + technology.

+

+ When planning simpler networks, the three-layer model should still be + considered as it may provide for better network scalability. The hub + at the center of a two-layer model is also a core, but with no other + core routers connected to it. Likewise, in a single-layer solution the + area hub serves as the regional hub and the core hub. This allows easy + and rapid future growth as the basic design can be replicated to add + new service areas.

+

    +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_5/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_5/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_5/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_5/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_5/media.html new file mode 100644 index 0000000..24d5797 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_5/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/buttons.html new file mode 100644 index 0000000..03085d1 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/buttons.html @@ -0,0 +1,110 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + + +
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+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/content.html new file mode 100644 index 0000000..21d1e0c --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/content.html @@ -0,0 +1,73 @@ + + + + + + + + +Content + + + + + + + + + + + + + + + + + + + +
+ + 2.3 + WAN Design 
  + 2.3.6 + Other WAN design considerations 
+ + + + + + +
+ + Many enterprise WANs will have connections to the Internet. This + poses security problems but also provides an alternative for + inter-branch traffic.

Part of the traffic that must be considered during design is going to + or coming from the Internet. Since the Internet probably exists + everywhere that the enterprise has LANs, there are two principal ways + that this traffic can be carried. Each LAN can have a connection to + its local ISP, or there can be a single connection from one of the + core routers to an ISP. The advantage of the first method is that + traffic is carried on the Internet rather than on the enterprise + network, possibly leading to smaller WAN links. The disadvantage of + permitting multiple links, is that the whole enterprise WAN is open to + Internet-based attacks. It is also difficult to monitor and secure the + many connection points. A single connection point is more easily + monitored and secured, even though the enterprise WAN will be carrying + some traffic that would otherwise have been carried on the Internet.

If each LAN in the enterprise has a separate Internet connection, a + further possibility is opened for the enterprise WAN. Where traffic + volumes are relatively small, the Internet can be used as the + enterprise WAN with all inter-branch traffic traversing the Internet. + Securing the various LANs will be an issue, but the saving in WAN + connections may pay for the security.

Servers should be placed closest to the locations that will access + them most often. Replication of servers, with arrangement for off-peak + inter-server updates, will reduce the required link capacity. Location + of Internet-accessible services will depend on the nature of the + service, anticipated traffic, and security issues. This is a + specialized design topic beyond the scope of this curriculum. + +

  

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/index.html new file mode 100644 index 0000000..82a25be --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/media.html new file mode 100644 index 0000000..1566913 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_3_6/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/buttons.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/buttons.html new file mode 100644 index 0000000..4907005 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/buttons.html @@ -0,0 +1,108 @@ + + + + + + + + + + + +New Page 1 + + + + + + + + + + + + + + + + + + + + + + + +
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+ + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/content.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/content.html new file mode 100644 index 0000000..755b3bf --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/content.html @@ -0,0 +1,94 @@ + + + + + + + + +Content + + + + + + + + + + +
+ Summary
+ + + + + + +
+ + An understanding of the following key + points should have been achieved:
    +
  • + + Differences in the geographic areas served + between WANs and LANs
    • +
  • + + Similarities in the OSI model layers involved + between WANs and LANs
    • +
  • + + Familiarity with WAN terminology + describing equipment, such as CPE, CO, local loop, DTE, DCE, CSU/DSU, + and TA
    • +
  • + + Familiarity with WAN terminology + describing services and standards, such as ISDN, Frame Relay, ATM, + T1, HDLC, PPP, POST, BRI, PRI, X.25, and DSL
    • +
  • + + Differences between packet-switched and + circuit-switched networks
    • +
  • + + Differences and similarities between + current WAN technologies, including analog dialup, ISDN, leased line, + X.25, Frame Relay, and ATM services
    • +
  • + + Advantages and drawbacks of DSL and cable + modem services
    • +
  • + + Ownership and cost associated with WAN + data links
    • +
  • + + Capacity requirements and transit times + for various WAN traffic types, such as voice, data, and video
    • +
  • + + Familiarity with WAN topologies, such as + point-to-point, star, and meshed
    • +
  • + + Elements of WAN design, including + upgrading, extending, modifying an existing WAN, and recommending a + WAN service to an organization based on its needs
    • +
  • + + Advantages offered with a three-layer + hierarchical WAN design
    • +
  • + + Alternatives for interbranch WAN traffic
    • +
+

      +

+ + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/index.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/index.html new file mode 100644 index 0000000..8583b88 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/index.html @@ -0,0 +1,29 @@ + + + + +Cisco Global Learning Network + + + + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/media.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/media.html new file mode 100644 index 0000000..5e5bba7 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/2_4_1/media.html @@ -0,0 +1,21 @@ + + + + + + +Flash Graphic + + + + + + + + + + + + \ No newline at end of file diff --git a/Bachelor/CCNA4/en_CCNA4_v30/ch2/main.html b/Bachelor/CCNA4/en_CCNA4_v30/ch2/main.html new file mode 100644 index 0000000..2549ff7 --- /dev/null +++ b/Bachelor/CCNA4/en_CCNA4_v30/ch2/main.html @@ -0,0 +1,26 @@ + + + + +Cisco Networking Academy Program + + + + + + + + + + + + + <body> + + <p>This page uses frames, but your browser doesn't support them.</p> + + </body> + + + + \ No newline at end of file -- cgit v1.2.3