How to display all ISIS routes

[ChuckMcF]

Can anyone provide the command that will show all routes learned for a specific network? This is not just the installed routes, but all other routes as well. Any help would be appreciated.

[luis_cordova]

Hi @ChuckMcF,

Other “Show IP Route” command options

show ip route [ip address] : shows only information about the specified IP address.

show ip route [ospf, rip, eigrp, isis, etc] : shows only routing information learned from the specified routing protocol (e.g show ip route ospf).

show ip route static : displays information about statically configured routes.

show ip route connected : displays information about directly connected networks.

show ip route summary : shows summary information about ALL IP routes in the routing table.

I hope this can help you.

Regards

[Harold Ritter]

Try "sh isis rib"

Regards,

[ChuckMcF]

Thank you for your reply. My initial thought was that the rib should have all information however I am not seeing all available routes which is what led to the post. To further explain what I'm seeing:

sh isis rib only shows the installed routes, or at least doesn't show all of the available routes. For example, let's say I have Routers A, B, C and D. They connect this way all with 10G uplinks: A<->B<->C<->D<->A. If all routes have default metric of 10 and I'm logged into RouterC I have equal cost uplinks (metric 20) to RouterA. If I change the metric on RouterC's interface from C<->D to metric 50 I only see the route to A via RouterB (metric 20). When I do a sh isis rib <RouterA's IP and mask> the only route displayed is the installed route [115/L1/20]. There is another route [115/L1/60] which also exists because the link to RouterD is still up however it doesn't show up in sh isis rib.

When I change the metric on RouterC's interface from C<->D back to metric 10 I see both routes as [115/L1/20] in sh isis rib.

[Harold Ritter · Accepted solution]

Thanks for the additional information. The reason you are not seeing the alternate path(s), is that ISIS only calculates the shortest path(s) by default. If you want ISIS to calculate an alternate path you need to configure Loop Free Alternate (LFA).

Regards,

[ChuckMcF]

Thank you for your reply. Makes perfect sense!