Cisco's Consistent Inconsistencies

Recently, I was working on our Cisco 3560E switch. I needed to create a route-map and apply it to an interface for some changes we were planning to make. I was able to create the route-map, but it wouldn’t allow me to apply it to the interface with the “ip policy route-map” command. After doing some research I realized to apply a route-map to an interface for policy-based routing our switch had to be licensed for “IP Services.” The command wasn’t even available, which makes sense being that it wasn’t supported. While upgrading the license; I tried to apply the “ip policy route-map” command again. I did a “sh run int vlan 1” to see if the command was showing up in the config and to my surprise it wasn’t listed!  I went back to the documentation and found the route-map command “set ip default next-hop” was not supported at all on the 3560/3750 switch platforms. I removed this command from my route-map and applied the route-map to the interface and everything seemed to apply correctly. Unfortunately, our whole plan revolved around the ability to use the “set ip default next-hop” command.

So when you are working with Cisco equipment there are at least 3 ways they let you know a command isn’t supported in the IOS:[more]

  1. The logical way:  The command isn’t present in IOS and it can’t be used.
  2. The illogical way: Allow you to apply a command, but doesn’t prompt you with an error if another “child” command is not supported.  This can only be discovered if you review the configuration and see that the command you entered is nowhere to be found.
  3. And what I like to call “The Cisco Way”:  Include the command in the IOS to lead users to believe that the command is supported and works with that IOS/platform all the while not supporting the command in any variation of the IOS/Platform.

After further review, the documentation did have a note that stated the command we needed wasn’t supported on these platforms.  In summary, it is a good idea to fully read any and all documentation on supported/unsupported commands for a platform.  

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