Re: [Idr] Question regarding bgpM2AsPath4byteTable in BGP4 MIBv2
"tom.petch" <cfinss@dial.pipex.com> Tue, 18 December 2007 16:42 UTC
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From: "tom.petch" <cfinss@dial.pipex.com>
To: Jeffrey Haas <jhaas@pfrc.org>
References: <44ED058B21DF294ABE394CABE5C1B52101303A58@EXCH-CLUSTER-03.force10networks.com> <20071217222552.GA12717@scc.mi.org>
Subject: Re: [Idr] Question regarding bgpM2AsPath4byteTable in BGP4 MIBv2
Date: Tue, 18 Dec 2007 16:39:16 +0100
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Jeff Camping onto a related topic .... Geoff Huston has picked up and developped the draft-michaelson-4byte-as-representation I-D that was last called here a year ago, and this now says that the representation MUST be asdot ie a decimal number below 65536, or x.y when it would be above 65535. This is gaining some traction in RIPE. If and when a standard is adopted, then I think that there should be a TC in this MIB with an appropriate DISPLAY-HINT (I cannot recall seeing anything like it anywhere). Tom Petch ----- Original Message ----- From: "Jeffrey Haas" <jhaas@pfrc.org> To: "Kalpesh Zinjuwadia" <kzinjuwadia@force10networks.com> Cc: <idr@ietf.org> Sent: Monday, December 17, 2007 11:25 PM Subject: Re: [Idr] Question regarding bgpM2AsPath4byteTable in BGP4 MIBv2 > Kalpesh, > > draft-ietf-idr-bgp4-mibv2-06 was issued prior to the last IETF. The > major focus of that re-issue was to clean up all of the previously > raised issues for the MIBv2 and also start the integration work into the > previously released BGP MIB. Unless you have some internal motivation > to support the old version of the mib as documented in -05, I'd consider > working on -06. > > -06 starts with the premise that 4 byte AS numbers are directly > supported. This does hide some of the internals of RFC 4893 when > operating in a 2 byte / 4 byte mode. There was no solid consensus as to > how much 2/4 byte detail to expose in the MIB when -05 was issued. > > In the context of the -06 MIB, if the details of the 2 / 4 byte mode > need to be exposed, it would be via an extension MIB similar to the > communities MIB documented in draft-jhaas-idr-bgp4-mibv2-community-00.txt > > Feedback from the IDR working group on the need for the extension MIB > for the additional objects for 2/4byte interaction would be helpful. > > In the context of the -05 draft: > > On Mon, Dec 17, 2007 at 10:39:58AM -0800, Kalpesh Zinjuwadia wrote: > > I had a question regarding how to fill up bgpM2AsPath4byteTable table as > > described in BGP4 MIBv2 (draft-ietf-idr-bgp4-mibv2). If a BGP speaker > > supports 4-byte AS space as described in RFC 4893 and stores the AS-PATH > > and AGGR attributes w/ 4-byte ASN, there won't be AS4-PATH and AS4-AGGR > > attributes in its RIB. It'll generate these attributes, if required, > > while advertising update to other speakers. > > One way to consider RFC 4893 is that if you're a 4 byte capable speaker, > and are participating in 4 byte peering sessions, you'll probably be > storing the AS Paths natively in 4 byte format. In that particular > case, the 4byte objects would have been absent. That detail wasn't > clear in the -05 draft. > > In the case of a 2-byte only speaker that implemented this MIB, or a > 4-byte capable speaker operating in 2-byte-only mode, the internal > versions of the ASes would be in 2 byte format and the additional path > attributes would be stored. > > After receiving a little feedback after -05 was issued, this seemed to > not be how people would be implementing this portion of the MIB. If the > BGP speaker was 2-byte-only, then it would likely treat the 4-byte > attributes as "unknown" and it would show up in the table for unknown > path attributes. > > > BGP4 MIBv2 has > > bgpM2AsPath4bytePathPresent entry in bgpM2AsPath4byteTable table. It's > > description says that it's true if a NEW speaker is functioning between > > 2-byte and 4-byte AS space. It further says that the AS4-PATH and > > AS4-AGGR are present in this NEW speaker. My question is - for > > implementation mentioned above, how to fill up this table as AS4-PATH > > and AS4-AGGR are not present and generated on need basis? Let me know if > > I'm missing something here... > > You haven't missed anything here. In essence, there are 3 potential > things to display in a MIB that could represent a 2-byte/4-byte > interaction: > > 1. What is being used internally. > 2. Received 2-byte managed objects > 3. Received 4-byte managed objects as NEW_ Path attributes. > > Given that a common criticism of the BGP MIB is that is too unwieldy to > start with, the -06 version of the MIB simply chooses #1. While #2 and > #3 could be represented in an extension MIB, the primary benefit would > seem to be for debugging 2byte/4byte interaction issues. MIBs seem to > be a particularly poor way to do this. > > My personal inclination would be to not include such a table as part of > the IETF standards, however I will yield to the consensus of the WG > should we wish one. > > -- Jeff > > _______________________________________________ > Idr mailing list > Idr@ietf.org > https://www1.ietf.org/mailman/listinfo/idr _______________________________________________ Idr mailing list Idr@ietf.org https://www1.ietf.org/mailman/listinfo/idr
- [Idr] Question regarding bgpM2AsPath4byteTable in… Kalpesh Zinjuwadia
- Re: [Idr] Question regarding bgpM2AsPath4byteTabl… Jeffrey Haas
- Re: [Idr] Question regarding bgpM2AsPath4byteTabl… tom.petch
- Re: [Idr] Question regarding bgpM2AsPath4byteTabl… Jeffrey Haas