Information Technology Reference
In-Depth Information
Table 12-5 outlines the problems that might cause this symptom and describes solutions to those
problems.
Table12-5 ISO CLNS: Host Cannot Access Hosts in Different Area
Possible Problem
Solution
Level 2 routers
are not routing
packets to the
correct area
1.
Use the
trace
command to verify that Level 1 routers are
routing packets to the nearest Level 2 router.
Sample Display:
The following display shows an example of ISO CLNS
trace
output:
router
# trace
Protocol [ip]: clns
Target CLNS address: thoth
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Type escape sequence to abort.
Tracing the route to THOTH
(55.0006.0100.0000.0000.0001.8888.1112.1314.1516)
HORUS(55.0006.0100.0000.0000.0001.6666.3132.3334.353
6) 32 msec ! 28 msec
28 msec !
2
ISIS(55.0006.0100.0000.0000.0001.7777.2122.2324.2526
)
56 msec ! 80 msec
56 msec !
3
THOTH(55.0006.0100.0000.0000.0001.8888.1112.1314.151
6) 80 msec ! 80 msec ! 8
Use the
trace
exec command to verify that Level 2 routers
are routing packets to the correct destination area.
2.
If packets are not being routed to the correct area, check the
Level 2 routing tables (ISO-IGRP
1
) or the Level 2 link state
databases (IS-IS) to see whether the packets are being
forwarded to another area.
3.
If necessary, reconfigure routers with the correct area
addresses and Level 2 (IS-IS) routing information.
4.
ES host is not
running ES-IS
protocol
1.
Use the appropriate host commands to verify that an ES-IS
process is running. If necessary, initiate the ES-IS process on
the host.
2.
Check the adjacency database on the host and verify that it
has an entry for its directly connected router.
3.
Use the
debug clns packet
privileged exec command on the
Level 1 router to verify that it sees and forwards packets
from the ES.
