Information Technology Reference
In-Depth Information
DECnet: Routing Node Adjacencies Toggle Up and Down
Symptom:
Routing adjacencies toggle up and down. Output such as the following appears repeatedly
on the DEC system console:
%%%%%%%%%%% OPCOM 30-JUN-1993 1:25:07.45 %%%%%%%%%%%%
Message from user DECNET on The Bay
DECnet event 4.16, adjacency rejected
From NODE 12.1 (The Bay), 30-JUN-1993 1:25:07.45
Circuit UNA-0, Adjacent node = 1.101 (Vax1)
%%%%%%%%%%% OPCOM 30-JUN-1993 1:25:07.46 %%%%%%%%%%%%
Message from user DECNET on The Bay
DECnet event 4.15, adjacency up
From NODE 12.1 (The Bay), 30-JUN-1993 1:25:07.46
Circuit UNA-0, Adjacent node = 1.12 (Vax2)
This output indicates that routers are constantly being added to and removed from the routing table. The
OPCOM messages specify DECnet events 4.16 (adjacency rejected) and 4.15 (adjacency up) for specific
routing nodes.
Table 11-6 outlines the problems that might cause this symptom and describes solutions to those
problems.
Table11-6
DECnet: Routing Node Adjacencies Toggle Up and Down
Possible Problem
Solution
Total number of
routing nodes on
network segment
is more than 32
DECnet limits the number of adjacencies that can be established
by a router to 32.
Enable the
debug decnet events privileged exec
command
to determine whether the adjacency is being rejected. Enable
this command on one router at a time.
1.
If the adjacency is being rejected, reduce the number of
adjacent routers on the segment.
2.
Hardware
problem
Check the error message output to identify the routing node or
nodes that are causing the adjacency to toggle.
Follow the procedures outlined in Chapter 3, “Troubleshooting
Hardware and Booting Problems.”
DECnet: No Phase IV Connectivity over Phase V Backbone
Symptom:
Communication between DECnet Phase IV areas separated by an ISO CLNS (Phase V)
backbone fails. Phase IV nodes cannot communicate with other Phase IV nodes across a Phase V cloud.
However, nodes can communicate with one another within the same Phase IV cloud.
For more information about troubleshooting DECnet /OSI internetworks, see Chapter 12,
“Troubleshooting ISO CLNS.”
Note
