Static Frame-Relay Addressing

Summary

If a Frame-Relay network is not fully meshed, meaning there is not a PVC (Private Virtual Connection) between every host on the network, then nodes without PVC's will have difficulty communicating with each other. Both their Frame-Relay interfaces will  lie on the same IP network, but they will have no medium to communicate. This document describes how to use static host routes (HS) to override the learned routes. 

Symptom

  • Cannot telnet between remote routers/LANs via a centrally Frame-Relay attached router.
  • Cannot traceroute to remote router's local Frame-Relay address but can ping. This is due to the source address used by traceroute versus ping.

Solution

Add static host routes at each POP (Point of Presence) Router to the other POP Routers' local Frame-Relay IP address (their WAN port address). All POP Routers should have their default gateway pointing to the Frame-Relay interface (WAN port connected to the Frame-Relay network) of the central router which should have a PVC to each POP router.

Example:

Remote POP           Central Router           Remote POP
pm2er/a |---------------- IRX -----------------| pm2er/b
            |                              |
            |======Frame Relay Cloud ======|

  • irx s1 local interface IP address = 192.168.2.33
  • dlci = 16:192.168.2.34 17:192.168.2.35
  • pm2er/a w1 local IP address = 192.168.2.34
  • dlci = 16:192.168.2.33
  • pm2er/b w1 local IP address = 192.168.2.35
  • dlci = 16:192.168.2.33

Command Entries Needed

Make the following entry to the PM-2ER (TM)/b's route table.

add route 192.168.2.34 192.168.2.33 1
save all

Make the following entry to PM-2ER/a's route table.

add route 192.168.2.35 192.168.2.33 1
save all

Default gateway at both PM-2ER's must point to the central router's Frame IP address.

set gateway 192.168.2.33
save all