Re: [Idr] [GROW] Review of draft-ietf-grow-bgp-reject-05

"Alvaro Retana (aretana)" <> Wed, 19 April 2017 18:45 UTC

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From: "Alvaro Retana (aretana)" <>
To: Jared Mauch <>
CC: John G Scudder <>, Chris Morrow <>, "" <>, "" <>, "" <>
Thread-Topic: [GROW] [Idr] Review of draft-ietf-grow-bgp-reject-05
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Date: Wed, 19 Apr 2017 18:45:21 +0000
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Subject: Re: [Idr] [GROW] Review of draft-ietf-grow-bgp-reject-05
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On 4/19/17, 10:03 AM, "Jared Mauch" <> wrote:


> Are you saying that IOS-XR is non-compliant with 9.1.1 because it does not have “bgp 
> unsafe-ebgp-policy” as the default?  

No.  I wasn’t talking about any specific implementation.

One of the reasons I like your document is the fact that rfc4271 is not specific about what should be done if there is no policy – it just says that policy may be applied.  From that point of view, the XR implementation is neither compliant nor non-compliant.

> At what point does the Cisco implementation make that decision?
> We seem to be triangulating on where in the exact decision process people are 
> considering a route feasible or ineligible, can you speak to your implementation?  That 
> may provide guidance in documenting the IOS-XR practice.

The XR implementation makes the decision while processing the Update messages.  Specifically, it drops all the routes from a peer without an incoming policy configured.  IOW, it acts as if a deny-all filter existed.

In the conceptual model in rfc4271, the routes are not even put in the Adj-RIB-In.  

Compared to the current text (in -05), there would be no routes to mark as ineligible in 9.1.1.   The text I proposed also assumed that the routes would at least be received/stored.

If you want the same behavior as XR then you would have to make the change in Section 9. (UPDATE Message Handling).