edit or rewrite a route-policy on xr?

[jorgeacat]

I want to edit a route-policy , but to me is easier to rewrite via cli, what is the difference of use a editor (vi, nano ) vs cli, Pros, Cons?

Thanks

[smailmilak]

Hi Jorgeacat,



All I can say is that editing is not always working (in case of BGP). Many times the RPL rule was not applied, i.e. specific route was not advertied even the config was ok. Only after rewrite in configed mode and commit the new rule was working. This must be a bug.



Btw. I like to edit RPL in vi because it's much cooler but I am not doing it anymore because of this issue. Maybe I should contact TAC.

[thecrev]

If you edit the policy:

1. you don't have to rewrite the whole thing (of course copy and paste is always an option)

but more importantly:

2. the policy gets applied automatically, without any "downtime" or extra steps

If you just "rewrite" the policy, the old policy has to be removed first, then you have to apply the new policy. As you can imagine, this causes some "downtime" so to speak in your routing, until you've applied the new policy. In most service provider situations, this isn't acceptable.

My advice would be to always edit your routing policies.

[smailmilak]

We are almost always using rewrite if we need to edit the RPL and there was never a downtime.

What about you, did you see a downtime while using rewrite? If yes, in what case?

Like I write previously, edit is nice but it's not triggering the RPL everytime. I've lost a lot of time because I was using edit and BGP was not sending the routes because the RPL was not triggered. Only using rewrite did the trick.

[endeavor · Accepted solution]

(and I just realized that I'm logged in as 'work', not jasoncrev)

Maybe I'm misunderstanding what you mean by rewrite. I've always edited in XR using a text editor.

Here is the part of the docs that I was referring to:

Attached Policy Modification
Policies that are in use do, on occasion, need to be modified. Traditionally, configuration changes are done by completely removing the relevant configuration and then re-entering it. However, this allows for a window of time in which no policy is attached and the default action takes place. RPL provides a mechanism for an atomic change so that if a policy is redeclared, or edited using a text editor, the new configuration is applied immediately—which allows for policies that are in use to be changed without having a window of time in which no policy is applied at the given attach point.