System information

Troubleshooting ISO CLNS 12-277
ISO CLNS: Host Cannot Access Hosts on Local or Remote Network
Router between hosts
is down
Step 1 Use the trace exec command to check connectivity between routers and the source
ES.
Step 2 If the trace fails at a router, use the show clns neighbors exec command to see
which neighboring routers and ESs are recognized.
Sample Display:
The following is sample output from the show clns neighbors command. This
display is a composite of the show clns es-neighbor and show clns is-neighbor
commands:
router# show clns neighbors
System Id SNPA Interface State Holdtime Type Protocol
0000.0000.0007 aa00.0400.6408 Ethernet0 Init 277 IS ES-IS
0000.0C00.0C35 0000.0c00.0c36 Ethernet1 Up 91 L1 IS-IS
0800.2B16.24EA aa00.0400.2d05 Ethernet0 Up 29 L1L2 IS-IS
0800.2B14.060E aa00.0400.9205 Ethernet0 Up 1698 ES ES-IS
0000.0C00.3E51 *HDLC* Serial1 Up 28 L2 IS-IS
0000.0C00.62E6 0000.0c00.62e7 Ethernet1 Up 22 L1 IS-IS
0A00.0400.2D05 aa00.0400.2d05 Ethernet0 Init 24 IS ES-IS
Step 3
If neighboring routers and end systems are up, perform one of the following
procedures:
• For ISO-IGRP
8
, check the routing table and see whether the routes are being
learned. Use the show clns route exec command to display the routing tables.
• For IS-IS
9
, check the LSP
10
database to see whether the links are being reported
in link state advertisements. Check the IS-IS routing table to see whether the
routes are being installed in the routing table. Use the show isis database detail
exec command to display the routing tables.
Route redistribution
problem
Misconfigured route redistribution can cause connectivity problems. For specific
troubleshooting information, see the section “ISO CLNS: Redistribution Causes Routing
Problems” later in this chapter.
1 TCP/IP = Transmission Control Protocol/Internet Protocol
2 ES = end system
3 IS = intermediate system
4 NSAP = Network service access point
5 ES-IS = End System-to-Intermediate System
6 MAC = Media Access Control
7 NET = network entity title
8 IGRP = Interior Gateway Routing Protocol
9 IS-IS = Intermediate System-to-Intermediate System
10 LSP = Link State Protocol
Possible Problem Solution