Information Technology Reference
In-Depth Information
Table 10-12 outlines the problems that might cause this symptom and describes solutions to those
problems.
Table10-11 SDLC: Sessions Fail over Router Running STUN
Possible Problem
Solution
Peers that are not
open
1.
Use the
show stun
exec command to see whether the peers
are open. If the peers are open, one of the other problems in
this table is probably the cause.
The following is sample output from the
show stun
command:
Router#
show stun
This peer: 131.108.10.1
Serial0 -- 3174 Controller for test lab (group 1
[sdlc])
state rx-pkts tx-pkts
drops poll
7[ 1] IF Serial1
open
20334
86440
5 8P
10[ 1] TCP 131.108.8.1
open
6771
7331
0
all[ 1] TCP 131.108.8.1
open
612301 2338550
1005
Peers that are not
open
(continued)
In this display, the first entry reports that proxy polling is enabled
for address 7, and serial 0 is running with modulus 8 on the
primary side of the link. The link has received 20,334 packets,
transmitted 86,440 packets, and dropped 5 packets.
2.
If the peers are not open, use the
debug stun
command on
the core router to see whether the peers are trying to open.
Peers do not open if there is no traffic on the link.
Caution:
Do not enable
debug
commands on a heavily loaded
router. Doing so can cause performance and connectivity
problems. Use a protocol analyzer or
show
commands instead.
3.
If you do not see the peers trying to open, use the
show
interface
exec command to make sure that the interface and
line protocol are both up. If they are not both up, there could
be a link problem. Proceed to the problem “SDLC physical
or link layer problem,” later in this table.
4.
If the peers are trying to open, use the
show running-config
privileged exec command to make sure that the
stun route
and other STUN configuration commands are configured
correctly. Reconfigure the router, if necessary.
5.
Use the
debug stun packet
privileged exec command on the
core router. Look for SNRMs or XIDs being sent.
6.
If you do not see SNRMs or XIDs, there is probably a basic
link problem. See the problem “SDLC physical or link layer
problem,” later in this table.
7.
Check to make sure that no other network problems are
occurring, such as interface drops, buffer misses, overloaded
Frame Relay switches, and IP routing problems.
