[Rmt] AD comments on draft-ietf-rmt-pi-alc-revised-06
Magnus Westerlund <magnus.westerlund@ericsson.com> Fri, 17 April 2009 16:12 UTC
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Date: Fri, 17 Apr 2009 16:08:28 +0200
From: Magnus Westerlund <magnus.westerlund@ericsson.com>
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Subject: [Rmt] AD comments on draft-ietf-rmt-pi-alc-revised-06
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Hi, I have reviewed the ALC PI and have some comments. 1. If one compare this one with the experimental one they are very similar. At least my expectation would be that a bit more details are actually nailed down on how one should do them to achieve interoperable implementations. For example the choice of congestion control algorithm. I think we only have one that we can really use to satisfy the intended usage of large scale sessions. Why isn't this a required to implement feature? The same thing can be said about normative to implement security features. Yes, here there are choices, but still specify one required to implement should be possible. If you have observant the NORM PI got this comment from the SECdir reviewer. And I think he was right, we should be clear on these. A question is if we need to specify one mandatory to implement FEC encoding? In general I am not against the flexibility the protocol allows for. However, it should be clear what you do need to implement for a base-line implementation. 2. Section 2, third paragraph: "This specification defines ALC as payload of the UDP transport protocol [RFC0768] that supports IP multicast delivery of packets. Future versions of this specification, or companion documents may extend ALC to use the IP network layer service directly. ALC could be used as the basis for designing a protocol that uses a different underlying network service such as unicast UDP, but the design of such a protocol is outside the scope of this document." This type of text seems out of place. You are not any longer describing a experimental protocol. State what is, not what could have been. Also the ALC PI would not work from a congestion control side over unicast IP. 3. I am also disappointed that the ID nits hasn't been taking care of: Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust Copyright Line does not match the current year -- The exact meaning of the all-uppercase expression 'MAY NOT' is not defined in RFC 2119. If it is intended as a requirements expression, it should be rewritten using one of the combinations defined in RFC 2119; otherwise it should not be all-uppercase. == The expression 'MAY NOT', while looking like RFC 2119 requirements text, is not defined in RFC 2119, and should not be used. Consider using 'MUST NOT' instead (if that is what you mean). Found 'MAY NOT' in this paragraph: All senders and receivers implementing ALC MUST support the EXT_NOP Header Extension and MUST recognize EXT_AUTH, but MAY NOT be able to parse its content. The EXT_NOP and EXT_AUTH LCT Header Extensions are defined in [I-D.ietf-rmt-bb-lct-revised] == The expression 'MAY NOT', while looking like RFC 2119 requirements text, is not defined in RFC 2119, and should not be used. Consider using 'MUST NOT' instead (if that is what you mean). Found 'MAY NOT' in this paragraph: If more than one object is to be carried within a session then the Transmission Object Identifier (TOI) MUST be used in the LCT header to identify which packets are to be associated with which objects. In this case the receiver MUST use the TOI to associate received packets with objects. The TOI is scoped by the IP address of the sender and the TSI, i.e., the TOI is scoped by the session. The TOI for each object is REQUIRED to be unique within a session, but MAY NOT be unique across sessions. Furthermore, the same object MAY have a different TOI in different sessions. The mapping between TOIs and objects carried in a session is outside the scope of this document. == The document seems to lack a disclaimer for pre-RFC5378 work, but was first submitted before 10 November 2008. Should you add the disclaimer? (See the Legal Provisions document at http://trustee.ietf.org/license-info for more information.). Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-09) exists of draft-ietf-rmt-bb-lct-revised-07 ** Obsolete normative reference: RFC 2327 (Obsoleted by RFC 4566) ** Downref: Normative reference to an Informational RFC: RFC 2357 ** Downref: Normative reference to an Experimental RFC: RFC 2974 -- Obsolete informational reference (is this intentional?): RFC 1889 (Obsoleted by RFC 3550) Yes, there is a difference between the draft submission check and the full checks that the tools page provide. At publication request time I do expect the draft be without real nits. 4. There are more references that are not updated. Cases where mechanism are available in IETF draft, like the TESLA solution. Which would impact the reference for example in Section 5, third paragraph. 5. Section 4.4: "If immediate checking is possible and if the packet fails the check then the receiver MUST discard the packet and reduce its reception rate to a minimum before continuing to regulate its reception rate using the multiple rate congestion control." Isn't the above instruction about reducing the rate based on packets that fails authentication checks resulting in another DoS vector on the receiver. If the only thing I need to do to keep the receiver at minimum reception rate is to send the occasional packet that fails the checks that seems extremely cheap. Can you please elaborate what the thoughts where on this? So in conclusion I think this document needs a work over and some nailing down on what is mandatory to implement. I am expecting a revised ID. Cheers Magnus Westerlund IETF Transport Area Director & TSVWG Chair ---------------------------------------------------------------------- Multimedia Technologies, Ericsson Research EAB/TVM ---------------------------------------------------------------------- Ericsson AB | Phone +46 10 7148287 Färögatan 6 | Mobile +46 73 0949079 SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com ----------------------------------------------------------------------
- [Rmt] AD comments on draft-ietf-rmt-pi-alc-revise… Magnus Westerlund
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Watson, Mark
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Magnus Westerlund
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Vincent Roca
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Magnus Westerlund
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Watson, Mark
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Rod.Walsh
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Magnus Westerlund
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Watson, Mark
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Magnus Westerlund
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Watson, Mark
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Magnus Westerlund
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Brian Adamson
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Watson, Mark
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Magnus Westerlund
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Watson, Mark
- Re: [Rmt] AD comments on draft-ietf-rmt-pi-alc-re… Watson, Mark