On Mon, May 14, 2012 at 6:34 AM, Benoit Claise <[email protected]> wrote: > Hi Richard, > > On Thu, May 10, 2012 at 10:37 AM, Benoit Claise <[email protected]> wrote: > > Dear all, > > I've been reviewing draft-ietf-alto-reqs-14 and the following requirement > got me thinking: > > REQ. ARv14-5: An ALTO client protocol MUST be extensible to enable > support of other host group descriptor types in future. An ALTO > client protocol specification MUST define an appropriate procedure > for adding new host group descriptor types, e.g., by establishing an > IANA registry. > > Why don't you reuse an existing registry, in which you will have all the > Information Elements already defined instead of defining a new one? > WhatI have in mind: the IPFIX I.E. IANA registry. > The piece of information I see in draft-ietf-alto-reqs-14 are IP address, > prefix, BGP AS: they're in IANA. > And many other IEs are already present, for future ALTO extensions, if > required. > > This would not only save one registry (ALTO Endpoint Property in > draft-ietf-alto-protocol-10), but offers a bigger advantage. > Let me explain.... When you will control your applications with ALTO, you > will anyway want to apply a flow measurement to monitor your changes, and to > serve as a feedback loop for more optimizations. > And the chances are high that you will using a NetFlow/IPFIX based > mechanism. Both NetFlow and IPFIX use the IPFIX I.E. IANA registry. > > Therefore, it would make sense to have consistent data models between ALTO > and IPFIX, and avoid a data model proxy if we want to compare the data. > Proposal: reuse the ElementIDs found in the IPFIX I.E. IANA registry > somewhere in your protocol. > > The suggested use case is in place of the Endpoint Property registry? > > I'm referring to the examples in > http://tools.ietf.org/html/draft-ietf-alto-protocol-11#section-7.5.3 > So I guess it's > http://tools.ietf.org/html/draft-ietf-alto-protocol-11#section-10.3. > However, http://tools.ietf.org/html/draft-ietf-alto-protocol-11#section-10.3 > doesn't contain the initial series of values.
Those are two different things in the protocol. The former is for identifying endpoints themselves, the latter is for properties associated with those endpoints. > > > Just to be sure I understand what would happen if we went that route, > what are the restrictions for adding new information elements? > Specifically, what kinds of elements are allowed or disallowed? > > Things that have been informally discussed in the ALTO WG so far have > been things like load information and available network capacity. Do > those fit within the ipfix model? > > The IANA considerations for new IPFIX IEs is in RFC5102, > http://tools.ietf.org/html/rfc5102#section-7.1. > It mentions: IANA through Expert Review [RFC2434] > The most up to date document regarding IE allocation is > http://tools.ietf.org/html/draft-ietf-ipfix-ie-doctors-02. > I don't believe there are any limitations on for new IEs such as load > information and available network capacity. > Copying the IPFIX chairs and Brian Trammell. I think the main consideration here is whether IPFIX really is the canonical source (and is planned to be in the future) for data that an application (note: not only network operator) would want to know about an endpoint. In particular, in the CDN use cases, an ALTO map may be provided by a CDN to advertise costs to/from and properties of various cache nodes. >From RFC5102, Section 2.1 I see that a registration seems to enforce that the Information Element is derived from a flow or someone observing the flow on the network: description - The semantics of this Information Element. Describes how this Information Element is derived from the Flow or other information available to the observer. To me, that seems too restrictive for the ALTO model which is providing information to the application layer. Thanks, Rich > > Regards, Benoit. > > > Thanks, > Rich > > Disclaimer: I have not read the protocol details > > Regards, Benoit. > > > _______________________________________________ > alto mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/alto > > > _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
