WAN technology-Frame Relay

WAN technology is a cross-region data communication network. The device provided by the telecom operator serves the customer as an information output platform. WAN technology is mainly located at the OSI physical layer, data link layer, and network layer.

What are the types of WAN technologies?

1. point-to-point connection: it is also called a leased line connection. The so-called leased line is where the operator pulls a leased line directly. A permanent fixed connection can be established between the receiving and receiving sides of the data, and the network operator is responsible for management and maintenance.

Advantage: it is self-evident that because it is a leased line, the speed is very fast and the latency is small. Some service providers maintain the stability of course.

Disadvantage: the cost is too high.

2. circuit Switching Network: The operator establishes, maintains, and terminates a dedicated physical circuit for each session of the Network, similar to dialing when making a call, the services using the circuit switching network include the ISDN Integrated Service Digital Network.

3. Packet Switching Network: Through packet switching, network devices can share a point to transfer data packets between devices through the operator network. Packet Switching mainly uses the statistical multiplexing technology to achieve circuit sharing. Such as frame relay, ATM, and X.25.

Frame-relay

Frame relay is a grouping method used to connect computer systems. It is mainly used for WAN connections. It provides protocol specifications for the data link layer and the physical layer. Frame Relay is an advanced WAN technology.

Advantages: high bandwidth utilization, low network latency, and low device costs.

Frame Relay bandwidth control technology: Frame Relay bandwidth control is completed by three parameters.

1. Information Rate promised by CIR

2. The burstable size promised by Bc

3. burst size exceeded by Be

There are also two parameters, Tc commitment interval, EIR information rate exceeding, Tc = Bc/cir eir = Be/Tc.

Specific process: the user applies for a frame relay circuit with a CIR speed of 64 KB/s at the service provider, and negotiates the promised burst size and the burst size, when the network is smooth, you can get a bandwidth that exceeds the predefined rate.

Frame Structure of the frame relay group:

The frame relay header contains the following information:

1. Data Link connection identifier DLCI: it indicates the logical connection from multiplexing to the Channel

2. Forward congestion report FECN: used to notify the router of congestion on the road where the frame received ].

3. Backward Congestion report BECN: The frames sent to the source sender are congested on the road and notified to the source sender]

Experiment: Simulate Frame Relay

Tutorial topology:

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Port and ip planning ---------

Beijing headquarters router: f0/0: 192.168.1.1/24 s1/0: Master ip192.168.4.1/24 auxiliary 192.168.5.1/24

Shanghai Branch router: f0/0: 192.168.2.1/24 s1/0: 192.168.4.2/24

Guangzhou Branch router: f0/0: 192.168.3.1/24 s1/0: 192.168.5.2/24

SW1 + SW2 + SW3 simulate the frame relay switch of the network operator

Beijing --- Shanghai pipeline No.: 100 101 102

Beijing --- Guangzhou pipeline No.: 200 201 202

Note: To enable the frame relay function on a vswitch, you must enable the command --- "frame-relay switching !!

Configuration content:

1. the user port is always the DTE interface, and the service provider port is the DCE interface.

2. Three types of cisco ansi q933a in LMIS signaling format]

3. line console 0 logging synchronous noexec-timeout

4. Enable s0/0 no shutdown

5. Set the frame relay port: interface serial 0/0 encapsulation frame-relay

6. Set the port type frame-relay intf-type dce clock.] clock rate 64000

7. lc-mstp signaling format: frame-relay lc-typecisco

8. Frame Relay forwarding table:

Frame-relay route 100 interface serial 0/1 101

Frame-relay route 200 interface serial 0/2 201

Frame relay node:

SW1 ---"

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SW2 ---"

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SW3 ---"

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Route configurations of each branch ---

Beijing headquarters:

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Shanghai Branch:

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Guangzhou Branch:

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Test:

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The preceding figure shows how to manually set the dling between the DLCI and automatically obtain the ip address and the DLCI through iarp,

But as mentioned in the above experiment topology, on the router of the Beijing headquarters, two IP addresses are set in the same port s1/0, 192.168.4.1 is the primary IP address, and 192.168.5.1 is the secondary IP address. When iarp is set to be automatically obtained, it is bound to the channel based on the main IP Address by default. Therefore, the ing on the router of the Shanghai branch is correct, however, the ing on the router in Guangzhou is not correct.

Verification:

Delete all mappings in the experiment.

Beijing (config-if) # noframe-relay map ip 192.168.4.2

Beijing (config-if) # noframe-relay map ip 192.168.5.2

Shanghai (config-if) # noframe-relay map ip 192.168.4.1

Guangzhou (config-if) # noframe-relay map ip 192.168.5.1

Enable ivrp on port s1/0]

Beijing (config-if) # frame-relayinverse-arp

Shanghai (config-if) # frame-relayinverse-arp

Guangzhou (config-if) # frame-relayinverse-arp

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We set the default route to 5.1 on the router of the Guangzhou Branch.

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Therefore, if dynamic iarp is used, it is not feasible to enable IARP alone.

The result is that the Shanghai branch can communicate with the Beijing headquarters !!

However, the Guangzhou Branch does not communicate with the other two !!

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The reason is: The IARP packet comes from 192.168.4.1, and after the router of the Guangzhou Branch receives the packet, it moves step by step from the 202 pipeline to the port of 192.168.4.1. Obviously, it cannot be reached!

Solution: configure the sub-port !!

Method for configuring sub-interfaces: interface type No.. point-to-point/point-to, for example: interface serial1/0.1

Configuration content: Before configuration, you must first Delete the IP address information of the relevant port and the dlci ing.

Beijing headquarters:

Beijing (config) # interfaceserial 1/0. 1 point-to-point

Beijing (config-subif) # ipaddress 192.168.4.1 255.255.255.0

Beijing (config-subif) # frame-relayinterface-dlci 100

Beijing (config) # interfaceserial 1/0. 2 point-to-point

Beijing (config-subif) # ipaddress 192.168.5.1 255.255.255.0

Beijing (config-subif) # frame-relayinterface-dlci 200

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