Section 6: DLSw (4 Points)

• The network manager deems the Frame Relay service to be susceptible to packet loss and requires that only TCP is used for DLSw+ features such as address resolutionpackets and unnumbered information frames. With this in mind, configure DLSw between VLAN3 and VLAN2. Peer from R4-R1 and R4-R6. Use the most appropriate encapsulation and peering method.

You should obviously use TCP as your encapsulation type here but the question gives you additional information about the address resolution packets and unnumbered information frames. From this additional information, you should research these features and find that these are in fact transmitted by default in UDP to avoid congestion if errors are encountered. To ensure these features are transmitted reliably in TCP, you should configure R1 and R4 with the command dlsw udp-disable. You should be peering from loopback interfaces and configure VLAN2 and VLAN3 as the DLSw bridge points on your routers. If you have configured this correctly as shown in Example 2-66 through Example 2-68, you have scored 2 points.

Example 2-66. R1 Initial DLSw Configuration

 dlsw local-peer peer-id 10.1.1.1 dlsw remote-peer 0 tcp 10.4.4.4 dlsw bridge-group 1 dlsw udp-disable ! interface FastEthernet0/0 bridge-group 1 ! bridge 1 protocol ieee 

Example 2-67. R4 Initial DLSw Configuration

 dlsw local-peer peer-id 10.4.4.4 dlsw remote-peer 0 tcp 10.6.6.6 dlsw remote-peer 0 tcp 10.1.1.1 dlsw bridge-group 1 dlsw udp-disable ! interface FastEthernet0/0 bridge-group 1 ! bridge 1 protocol ieee 

Example 2-68. R6 Initial DLSw Configuration

 dlsw local-peer peer-id 10.6.6.6 dlsw remote-peer 0 tcp 10.4.4.4 dlsw bridge-group 1 dlsw udp-disable ! interface FastEthernet0/0 bridge-group 1 ! bridge 1 protocol ieee 

• Ensure both Frame Relay PVCs are utilized alternatively for each new circuit from R4.

Because you have duplicate paths to the end destination, you should configure DLSw round-robin load sharing with the command dlsw load-balance round-robin on R4. If you have configured this correctly, you have scored 1 point.

• Your network administrator complains of unnecessary DLSw traffic being sent over the network; keep the traffic off the network unless valid user traffic exists that is required to be sent between VLAN2 and VLAN3.

You need to configure dynamic peering, which will only initiate sessions when you have valid user traffic to transport. If you have configured this correctly as shown in Example 2-69 through Example 2-71, which also show the final DLSw configurations for R1, R4, and R6, you have scored 1 point.

Example 2-69. R1 Final DLSw Configuration

 dlsw local-peer peer-id 10.1.1.1 dlsw remote-peer 0 tcp 10.4.4.4 keepalive 0 timeout 90 dynamic dlsw bridge-group 1 dlsw udp-disable ! interface FastEthernet0/0 bridge-group 1 ! bridge 1 protocol ieee 

Example 2-70. R4 Final DLSw Configuration

 dlsw local-peer peer-id 10.4.4.4 dlsw load-balance round-robin dlsw remote-peer 0 tcp 10.6.6.6 keepalive 0 timeout 90 dynamic dlsw remote-peer 0 tcp 10.1.1.1 keepalive 0 timeout 90 dynamic dlsw bridge-group 1 dlsw udp-disable ! interface FastEthernet0/0 bridge-group 1 ! bridge 1 protocol ieee 

Example 2-71. R6 Final DLSw Configuration

 dlsw local-peer peer-id 10.6.6.6 dlsw remote-peer 0 tcp 10.4.4.4 keepalive 0 timeout 90 dynamic dlsw bridge-group 1 dlsw udp-disable ! interface FastEthernet0/0 bridge-group 1 ! bridge 1 protocol ieee 

NOTE

The keepalive and timeout figures shown are the defaults.