Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02
<Ruediger.Geib@telekom.de> Fri, 15 August 2014 05:08 UTC
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From: Ruediger.Geib@telekom.de
To: brian.e.carpenter@gmail.com
Date: Fri, 15 Aug 2014 07:08:31 +0200
Thread-Topic: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02
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Subject: Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02
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Hi Brian, standards agree on the PHB which unrecognised DSCPs should receive, which is default forwarding. RFC2474 however proposes to transport the DSCP without remarking: Packets received with an unrecognized codepoint SHOULD be forwarded as if they were marked for the Default behavior (see Sec. 4), and their codepoints should not be changed. Such packets MUST NOT cause the network node to malfunction. The MUST NOT cause malfunction clause leaves a way out and I personally favor rewrite to default DSCP. There has been a discussion whether a rewrite of several incoming DSCP to a single outgoing DSCP is DiffServ compatible or not. Here we have such a rewrite. It seems to be alright for not supported DSCPs and PHBs. As you mention, a TCA/SLA stating treatment of all DSCPs is important at network domain boundaries. Regards, Ruediger -----Ursprüngliche Nachricht----- Von: Dart [mailto:dart-bounces@ietf.org] Im Auftrag von Brian E Carpenter Gesendet: Donnerstag, 14. August 2014 21:58 An: Geib, Rüdiger Cc: gorry@erg.abdn.ac.uk; dart@ietf.org Betreff: Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 > Another question to be answered then is how a network provider will treat unrecognized or unexpected DSCPs received at network boundaries. Quoting RFC 2475: "A DS domain has a well-defined boundary consisting of DS boundary nodes which classify and possibly condition ingress traffic to ensure that packets which transit the domain are appropriately marked to select a PHB from one of the PHB groups supported within the domain." In other words the assumption is that (unless there's an SLA that allows the receiving domain to trust the incoming DSCP), a classifier is needed. My assumption has always been that the default classifier will simply re-mark packets with the default DSCP. We also have "A DS ingress node is responsible for ensuring that the traffic entering the DS domain conforms to any TCA between it and the other domain to which the ingress node is connected." and the definition of a TCA: " Traffic Conditioning an agreement specifying classifier rules Agreement (TCA) and any corresponding traffic profiles and metering, marking, discarding and/or shaping rules which are to apply to the traffic streams selected by the classifier. A TCA encompasses all of the traffic conditioning rules explicitly specified within a SLA along with all of the rules implicit from the relevant service requirements and/or from a DS domain's service provisioning policy." In other words: the treatment of unrecognized DSCPs needs to be stated in the TCA part of the SLA. Of course you could suggest a default approach in diffserv-intercon. Brian _______________________________________________ Dart mailing list Dart@ietf.org https://www.ietf.org/mailman/listinfo/dart
- [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Ben Campbell
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Ruediger.Geib
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Black, David
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Brian E Carpenter
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Ruediger.Geib
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Brian E Carpenter
- Re: [Dart] [rtcweb] Fwd: WGLC: draft-ietf-dart-ds… Dave Taht
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Ruediger.Geib
- [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Gorry Fairhurst
- Re: [Dart] [rtcweb] Fwd: WGLC: draft-ietf-dart-ds… Brian E Carpenter
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Ruediger.Geib
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 gorry
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Brian E Carpenter
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Ruediger.Geib
- Re: [Dart] [AVTCORE] WGLC: draft-ietf-dart-dscp-r… Colin Perkins
- Re: [Dart] [AVTCORE] WGLC: draft-ietf-dart-dscp-r… Ben Campbell
- Re: [Dart] [AVTCORE] WGLC: draft-ietf-dart-dscp-r… Black, David
- Re: [Dart] WGLC: draft-ietf-dart-dscp-rtp-02 Ben Campbell