--- 1/draft-ietf-opsawg-large-flow-load-balancing-09.txt 2014-04-08 15:14:39.446827932 -0700 +++ 2/draft-ietf-opsawg-large-flow-load-balancing-10.txt 2014-04-08 15:14:39.494829075 -0700 @@ -1,26 +1,26 @@ OPSAWG R. Krishnan Internet Draft Brocade Communications Intended status: Informational L. Yong -Expires: October 5, 2014 Huawei USA +Expires: October 8, 2014 Huawei USA A. Ghanwani Dell Ning So Tata Communications B. Khasnabish ZTE Corporation - April 6, 2014 + April 8, 2014 Mechanisms for Optimizing LAG/ECMP Component Link Utilization in Networks - draft-ietf-opsawg-large-flow-load-balancing-09.txt + draft-ietf-opsawg-large-flow-load-balancing-10.txt Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, except to publish it as an RFC and to translate it into languages other than English. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that @@ -31,21 +31,21 @@ and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html - This Internet-Draft will expire on October 6, 2014. + This Internet-Draft will expire on October 8, 2014. Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -350,21 +350,21 @@ +-----+ +-----+ / \ \ / /\ / +---------+ / \ / / \ \ / \ / / \ +------+ \ / / \ / \ \ +-----+ +-----+ +-----+ | L1 | | L2 | | L3 | +-----+ +-----+ +-----+ - Figure 3: Two-level fat tree + Figure 3: Two-level Fat Tree To demonstrate the limitations of local optimization, consider a two- level fat-tree topology with three leaf nodes (L1, L2, L3) and two spine nodes (S1, S2) and assume all of the links are 10 Gbps. Let L1 have two flows of 4 Gbps each towards L3, and let L2 have one flow of 7 Gbps also towards L3. If L1 balances the load optimally between S1 and S2, and L2 sends the flow via S1, then the downlink from S1 to L3 would get congested resulting in packet discards. On the other hand, if L1 had sent both its flows towards S1 and L2 had @@ -697,21 +697,21 @@ | | -> | | | | -> | | | | ===> | | | (3)|--------|(3) | | | | | +-----------+ +-----------+ Where: -> small flow ===> large flow - Figure 4: Evenly utilized Composite Links + Figure 4: Evenly Utilized Composite Links Basically, the use of the mechanisms described in Section 4.4.1 resulted in a rebalancing of flows where one of the large flows on component link (3) which was previously congested was moved to component link (2) which was previously under-utilized. 5. Information Model for Flow Rebalancing In order to support flow rebalancing in a router from an external system, the exchange of some information is necessary between the