IOSXR runs commands not listed in help - Thoughts?

[John White]

Hi guys,

Not really a question, just an observation I stumbled on to while getting some OSPF verification practice in. I have ready access to production routers running multi-area OSPF, so I was running through various verification commands and trying different regular expressions. Initially I wasn't using the tab-completion option because I wanted to memorize the commands properly.

I found that when I ran show ip ospf interface | i "^B|^T|^G|interface that I got exactly what I would expect: A list of interfaces and their IPs in OSPF.

Ex:

RP/0/RSP0/CPU0:<hostnameredacted>#show ip ospf interface | i "^B|^T|^G|^F|Internet"
Fri Jan 29 10:33:52.551 EST
Bundle-EtherX is up, line protocol is up
Internet Address x.x.x.x/x, Area x 
Bundle-EtherX is up, line protocol is up
Internet Address x.x.x.x/x, Area x 
Bundle-EtherX is up, line protocol is up

However, when I went to explore additional options, for instance to see if I could use IOS help after interface to get a list of interfaces in OSPF, I got an invalid input detected message after ip.

Ex:

RP/0/RSP0/CPU0:<hostnameredacted>#show ip os?
                                                                               ^
% Invalid input detected at '^' marker.

I realized then that I was working inside IOSXR rather than just IOS, and in XR you drop the ip argument and designate which OSPF version you are querying. Clearly some code from IOS has carried over to XR because the OS still provided the desired output, despite the invalid input message when I tried to use the help function.

I am curious if anyone has also discovered this and if there are any especially useful IOS commands that have been found to work in XR that wouldn't normally be discoverable using the help feature.

Please also feel free to point out that I am stupid in some way, and enlighten me! :)

[Jean-Francois Dube]

Hi John,

In my experience, Cisco does this all the time when commands are about to be deprecated. In IOS, you usually get to use a deprecated command for a few version before you need to use the newer command. MPLS comes to mind when Cisco moved away from "show tag-switching" to "show mpls" and the lot. The tag-switching commands worked up to certain version of 12.2 code if memory serves but displayed something like this:

% Command accepted but obsolete, unreleased, or unsupported; see documentation

In the case of IOS XR, I believe the "show ip xyz" commands are supported only because they have been long in use on vanilla IOS. There are second nature to most networking people. But clearly the help feature will not work since these commands are not part of any official command reference for XR. I'm thinking Cisco may even drop support for them in the future. (Monolithic IOS is on the way out in my opinion.)

Bottom line, you'll need to read the command reference guides for your version of XR code to learn all commands available to you.

Goodbye "show ip route" and hello "show route ipv4 unicast" !

Hope this helps.

Cheers,

JF