BGP repropagation practices on not well known attributes

[Ondrej Zajicek]

On Thu, Feb 27, 2020 at 10:16:38PM +0100, Mattia Milani wrote:
> Hello bird users, I'm sorry to bother you but I have a question about the
> implementation of a piece of the RFC 4271 that I found a little bit fuzzy.
> 
> I'm in a eBGP situation and suppose that I have more connections with other
> different AS peers.
> Giving the fact that my import and export filters are completely open for
> simplicity and that I accept optional attributes.
> 
> When I receive an UPDATE where it changes only a optional transitive
> argument that i do not know I re-propagate the UPDATE to my other
> connections as like a well known mandatory argument is changed?
> 
> So my general question is, how Bird handle optional transitive attributes
> that a peer does not know?

Hello

First, handling of optional attributes depends on whether you knows them,
not on whether a peer knows them.

Unknown optional transitive attributes are re-propagated, but with set
'partial' flag. For details, see bgp_export_attr() function.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."