Dear all, As we are preparing for the slides on a potential ALTO topology extension (node-link graph), we have a few design choices that can benefit from some discussions in the WG list.
1. path vector vs flow Starting from -03, the document introduced the concept of a path vector mode as a generic mechanism to provide topology/routing information. Upon writing the slides, however, we found that to handle multi-path routing (e.g., ECMP), we will need a simple flow routing concept, where path vector is a special case. Any comments on extending to this direction will be appreciated. 2. property graph as a node-graph foundation Another design choice, when introducing node-link graph, is (1) adding network nodes in the network map, and hence we have a single place for all network nodes, and PID properties can provide properties for all such nodes; or (2) separate PIDs (endpoint user groups) from network nodes. This may be conceptually cleaner. Then it implies two types of links, which will be captured by property graphs. If you have any comments on this aspect, please share your opinions. 3. Subgraph selection API How to provide a generic mechanism to allow an ALTO client to select a subgraph is still not clear--it will depend on the use cases. So far, the first selection service is the expander of a given set of src/dst PIDs: the expander is the union of path vectors (or flows, if we consider multi-path). If you have any opinions on this aspect, please let us know. Cheers, Richard ---------- Forwarded message ---------- From: <[email protected]> Date: Mon, Oct 27, 2014 at 7:41 PM Subject: New Version Notification for draft-yang-alto-topology-05.txt To: Greg Bernstein <[email protected]>, Michael Scharf < [email protected]>, Wendy Roome <[email protected]>, Young Lee <[email protected]>, "Y. Richard Yang" <[email protected]> A new version of I-D, draft-yang-alto-topology-05.txt has been successfully submitted by Y. Richard Yang and posted to the IETF repository. Name: draft-yang-alto-topology Revision: 05 Title: ALTO Topology Extensions Document date: 2014-10-27 Group: Individual Submission Pages: 18 URL: http://www.ietf.org/internet-drafts/draft-yang-alto-topology-05.txt Status: https://datatracker.ietf.org/doc/draft-yang-alto-topology/ Htmlized: http://tools.ietf.org/html/draft-yang-alto-topology-05 Diff: http://www.ietf.org/rfcdiff?url2=draft-yang-alto-topology-05 Abstract: The Application-Layer Traffic Optimization (ALTO) Service has defined network and cost maps to provide basic network information. In this document, we discuss designs to provide abstracted graph representations of network topology. We start with a basic application use case of multi-flow scheduling using ALTO. We show that ALTO cost maps alone cannot provide sufficient information. We then define one key, generic component to address the issues: introducing path vectors in cost maps. We specify two approaches to complement path vectors and achieve a complete design: an approach using opaque network elements and another using a graph (node-link) representation. Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at tools.ietf.org. The IETF Secretariat
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