System information

Troubleshooting DECnet 11-263

DECnet: Routers Not Establishing Adjacencies

Symptom: Routers do not establish adjacencies with other routers on the same LAN.

Table 11-5 outlines the problems that might cause this symptom and describes solutions to those

problems.

Table 11-5 DECnet: Router Not Establishing Adjacencies

Adjacency between

nodes is not

bidirectional

Step 1 Use the show decnet route exec command to see whether the adjacency with the

expected designated router is in a “down” or “initializing” state.

Step 2 Use the debug decnet adj privileged exec command to determine whether hello

packets are being exchanged.

Caution: Because debugging output is assigned high priority in the CPU process, it

can render the system unusable. For this reason, use debug commands only to

troubleshoot speciﬁc problems or during troubleshooting sessions with Cisco

technical support staff. Moreover, it is best to use debug commands during periods

of lower network trafﬁc and fewer users. Debugging during these periods decreases

the likelihood that increased debug command processing overhead will affect

system use.

Step 3 If a router is not sending hello packets, use the show interfaces command to

determine whether the interface input and output queues are full. A full input queue

is indicated by a value of 75/75, and a full output queue is indicated by a value of

40/40.

Step 4 If the queues are full, and no hello packets are being exchanged, contact your router

technical support representative.

Adjacency between

nodes is not

bidirectional

Step 5 If routers are sending hello packets, contact end-node administrators to determine

why end nodes are rejecting hello packets.

Possible Problem Solution