Re: [Idr] Request to adopt draft-heitz-idr-large-community - Working Group Adoption call (9/6 to 9/20)

[Robert Raszuk <[e-mail]>]

Folks,

But this is not what the T flags (Transitive or Filter) are to be all
about. You can have one attribute in BGP UPDATE message ... but since we
are converging on common header there is nothing that prevents you to have
more then one common header of the same type.

One can differ with T flags, the other can differ with Context-AS.

Otherwise of course it would be pointless, but the above is the intention.

And while you can't trust what your peer does with your flag - you can
filter yourself by that flag and never send him something which one ingress
added to the message and is not intended to be send outside.

You enable send-all, you may enable send-type. But I hope no one here is
eager to match by community content on 100s of ebgp egress points to filter
it.

That is why T or D (same domain) or R flags are intended to be used for.

Cheers,
R.


On Wed, Sep 14, 2016 at 7:20 PM, Jared Mauch <[e-mail]> wrote:

> On Wed, Sep 14, 2016 at 07:07:19PM +0200, Sander Steffann wrote:
> > Hi,
> >
> > >> Attempting to impose policy on a 3rd party in this way
> > >> is an interesting suspension of reality.  Once you send it, you have
> > >> no control over what they use it for, and pretending otherwise is
> > >> wishing for something that will not happen.
> > >
> > > Yes, you can use RPL to override such things, but you're indicating
> intention
> > > AND you can also have free RPL as a result
> >
> > The big problem here is that these "intention indicating" flags are
> global for all the communities in the container, and as BGP only allows one
> path attribute of each type all the wide communities have to share the same
> fate. The sender cannot indicate which wide communities should be
> transitive and which should be not. This "all or nothing" approach isn't
> useful and will only create confusion. Better to just drop the flags field.
>
>         Thanks for putting it that way, I think that's helpful.
>
>         - jared
>
>
>
> --
> Jared Mauch  | pgp key available via finger from [e-mail]
> clue++;      | http://puck.nether.net/~jared/  My statements are only
> mine.
>