Re: [Idr] Choice of Large vs. Extended Community for Route Leaks Solution
Jeffrey Haas <jhaas@pfrc.org> Wed, 31 March 2021 21:38 UTC
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Date: Wed, 31 Mar 2021 18:00:48 -0400
From: Jeffrey Haas <jhaas@pfrc.org>
To: "Jakob Heitz (jheitz)" <jheitz@cisco.com>
Cc: "Sriram, Kotikalapudi (Fed)" <kotikalapudi.sriram@nist.gov>, Susan Hares <shares@ndzh.com>, "idr@ietf.org" <idr@ietf.org>, "grow@ietf.org" <grow@ietf.org>
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Subject: Re: [Idr] Choice of Large vs. Extended Community for Route Leaks Solution
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On Wed, Mar 31, 2021 at 06:02:52PM +0000, Jakob Heitz (jheitz) wrote: > No community is transitive. > Not even the transitive extended communities. > > In all BGP code I've worked in, not just Cisco, a configuration > is required to send communities of any kind to an ebgp session. > By default, no communities are sent to ebgp sessions. > That's a good thing, because network operators don't want > junk in the routes transiting across their networks, causing > churn and memory consumption. Contrarily, the implementations I've worked on don't have this behavior. But it's still a highly relevant point and perhaps what should probably be a useful rule of thumb across IETF working groups that deal with BGP: Because such a knob exists on multiple implementations, communities SHOULD NOT be used for any protocol transient signaling behaviors. > Path attributes are transitive. > However, several years ago, approximately coinciding with the > development of RFC7660, there was massive thrust to get attributes > blocked too. Now we implement path attribute filtering > and many network operators use it. Sadly, also yes. At least in my case, every discussion I have about the feature I note that it is toxic to the incremental deployment of new features in BGP. And similarly, that it is a toxic use case for someone paying them as a transit provider. -- Jeff
- [Idr] Choice of Large vs. Extended Community for … Sriram, Kotikalapudi (Fed)
- Re: [Idr] Choice of Large vs. Extended Community … Jeffrey Haas
- Re: [Idr] Choice of Large vs. Extended Community … Sriram, Kotikalapudi (Fed)
- Re: [Idr] Choice of Large vs. Extended Community … Jakob Heitz (jheitz)
- Re: [Idr] Choice of Large vs. Extended Community … Jeffrey Haas
- Re: [Idr] Choice of Large vs. Extended Community … Jeffrey Haas
- Re: [Idr] Choice of Large vs. Extended Community … Brian Dickson
- Re: [Idr] [GROW] Choice of Large vs. Extended Com… Randy Bush
- Re: [Idr] [GROW] Choice of Large vs. Extended Com… Gyan Mishra
- Re: [Idr] [GROW] Choice of Large vs. Extended Com… Jeffrey Haas
- Re: [Idr] [GROW] Choice of Large vs. Extended Com… Jeffrey Haas
- Re: [Idr] Choice of Large vs. Extended Community … Sriram, Kotikalapudi (Fed)
- Re: [Idr] [GROW] Choice of Large vs. Extended Com… Brian Dickson
- Re: [Idr] Choice of Large vs. Extended Community … Sriram, Kotikalapudi (Fed)
- Re: [Idr] Choice of Large vs. Extended Community … Brian Dickson
- Re: [Idr] [GROW] Choice of Large vs. Extended Com… Job Snijders
- Re: [Idr] Choice of Large vs. Extended Community … Jakob Heitz (jheitz)
- Re: [Idr] Choice of Large vs. Extended Community … Sriram, Kotikalapudi (Fed)