--- 1/draft-ietf-pim-drlb-14.txt 2020-01-03 14:13:13.480193965 -0800 +++ 2/draft-ietf-pim-drlb-15.txt 2020-01-03 14:13:13.524195089 -0800 @@ -1,24 +1,24 @@ Network Working Group Y. Cai Internet-Draft H. Ou Intended status: Standards Track Alibaba Group -Expires: June 13, 2020 S. Vallepalli +Expires: July 6, 2020 S. Vallepalli M. Mishra S. Venaas Cisco Systems, Inc. A. Green British Telecom - December 11, 2019 + January 3, 2020 PIM Designated Router Load Balancing - draft-ietf-pim-drlb-14 + draft-ietf-pim-drlb-15 Abstract On a multi-access network, one of the PIM-SM (PIM Sparse Mode) routers is elected as a Designated Router. One of the responsibilities of the Designated Router is to track local multicast listeners and forward data to these listeners if the group is operating in PIM-SM. This document specifies a modification to the PIM-SM protocol that allows more than one of the PIM-SM routers to take on this responsibility so that the forwarding load can be @@ -32,25 +32,25 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months 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." - This Internet-Draft will expire on June 13, 2020. + This Internet-Draft will expire on July 6, 2020. Copyright Notice - Copyright (c) 2019 IETF Trust and the persons identified as the + Copyright (c) 2020 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 (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as @@ -64,21 +64,21 @@ 4. Functional Overview . . . . . . . . . . . . . . . . . . . . . 5 4.1. GDR Candidates . . . . . . . . . . . . . . . . . . . . . 6 5. Protocol Specification . . . . . . . . . . . . . . . . . . . 7 5.1. Hash Mask and Hash Algorithm . . . . . . . . . . . . . . 7 5.2. Modulo Hash Algorithm . . . . . . . . . . . . . . . . . . 8 5.2.1. Modulo Hash Algorithm Examples . . . . . . . . . . . 9 5.2.2. Limitations . . . . . . . . . . . . . . . . . . . . . 10 5.3. PIM Hello Options . . . . . . . . . . . . . . . . . . . . 11 5.3.1. PIM DR Load Balancing Capability (DRLB-Cap) Hello Option . . . . . . . . . . . . . . . . . . . . . . . 11 - 5.3.2. PIM DR Load Balancing List (DRLB-List) Hello Option . 11 + 5.3.2. PIM DR Load Balancing List (DRLB-List) Hello Option . 12 5.4. PIM DR Operation . . . . . . . . . . . . . . . . . . . . 13 5.5. PIM GDR Candidate Operation . . . . . . . . . . . . . . . 14 5.6. DRLB-List Hello Option Processing . . . . . . . . . . . . 14 5.7. PIM Assert Modification . . . . . . . . . . . . . . . . . 15 5.8. Backward Compatibility . . . . . . . . . . . . . . . . . 16 6. Operational Considerations . . . . . . . . . . . . . . . . . 16 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 7.1. Initial registry . . . . . . . . . . . . . . . . . . . . 17 7.2. Assignment of new Hash Algorithms . . . . . . . . . . . . 17 8. Security Considerations . . . . . . . . . . . . . . . . . . . 17 @@ -454,20 +454,28 @@ 5.2.2. Limitations The Modulo Hash Algorithm has poor failover characteristics when a shared LAN has more than two GDRs. In the case of more than two GDRs on a LAN, when one GDR fails, all of the groups may be reassigned to a different GDR, even if they were not assigned to the failed GDR. However, many deployments use only two routers on a shared LAN for redundancy purposes. Future work may define new Hash Algorithms where only groups assigned to the failed GDR get reassigned. + The Modulo Hash Algorithm will use at most 32 consecutive bits of the + input addresses for its computation. Exactly which bits are used of + the source, group or RP addresses, depend on the respective masks. + + This limitation may be an issue for IPv6 deployments, since not all + bits of the IPv6 addresses are considered. If this causes + operational issues, a new hash algorithm would need to be defined. + 5.3. PIM Hello Options PIM routers include a new option, called "Load Balancing Capability (DRLB-Cap)" in their PIM Hello messages. Besides this DRLB-Cap Hello Option, the elected PIM DR also includes a new "DR Load Balancing List (DRLB-List) Hello Option". The DRLB- List Hello Option consists of three Hash Masks as defined above and also a list of GDR Candidate addresses on the LAN. It is recommended that the GDR Candidate addresses are sorted in descending order.