draft-ietf-pim-drlb-05.txt   draft-ietf-pim-drlb-06.txt 
Network Working Group Yiqun Cai Network Working Group Yiqun. Cai
Internet-Draft Microsoft Internet-Draft Heidi. Ou
Intended status: Standards Track Sri Vallepalli Intended status: Standards Track Alibaba Group
Expires: January 4, 2015 Heidi Ou Expires: December 30, 2017 Sri. Vallepalli
Cisco Systems, Inc. Mankamana. Mishra
Andy Green Stig. Venaas
Cisco Systems
Andy. Green
British Telecom British Telecom
July 3, 2014 June 28, 2017
PIM Designated Router Load Balancing PIM Designated Router Load Balancing
draft-ietf-pim-drlb-05.txt draft-ietf-pim-drlb-06
Abstract Abstract
On a multi-access network, one of the PIM routers is elected as a On a multi-access network, one of the PIM routers is elected as a
Designated Router (DR). On the last hop network, the PIM DR is Designated Router (DR). On the last hop LAN, the PIM DR is
responsible for tracking local multicast listeners and forwarding responsible for tracking local multicast listeners and forwarding
traffic to these listeners if the group is operating in PIM-SM. In traffic to these listeners if the group is operating in PIM-SM. In
this document, we propose a modification to the PIM-SM protocol that this document, we propose a modification to the PIM-SM protocol that
allows more than one of these last hop routers to be selected so that allows more than one of these last hop routers to be selected so that
the forwarding load can be distributed among these routers. the forwarding load can be distributed among these routers.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
skipping to change at page 1, line 40 skipping to change at page 1, line 42
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 4, 2015. This Internet-Draft will expire on December 30, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Functional Overview . . . . . . . . . . . . . . . . . . . . . 5 4. Functional Overview . . . . . . . . . . . . . . . . . . . . . 6
4.1. GDR Candidates . . . . . . . . . . . . . . . . . . . . . 6 4.1. GDR Candidates . . . . . . . . . . . . . . . . . . . . . 7
4.2. Hash Mask and Hash Algorithm . . . . . . . . . . . . . . 7 4.2. Hash Mask and Hash Algorithm . . . . . . . . . . . . . . 7
4.3. Modulo Hash Algorithm . . . . . . . . . . . . . . . . . . 8 4.3. Modulo Hash Algorithm . . . . . . . . . . . . . . . . . . 8
4.4. PIM Hello Options . . . . . . . . . . . . . . . . . . . . 9 4.4. PIM Hello Options . . . . . . . . . . . . . . . . . . . . 9
5. Hello Option Formats . . . . . . . . . . . . . . . . . . . . 9 5. Hello Option Formats . . . . . . . . . . . . . . . . . . . . 10
5.1. PIM DR Load Balancing Capability (DRLBC) Hello Option . . 9 5.1. PIM DR Load Balancing Capability (DRLBC) Hello Option . . 10
5.2. PIM DR Load Balancing GDR (DRLBGDR) Hello Option . . . . 10 5.2. PIM DR Load Balancing GDR (DRLBGDR) Hello Option . . . . 10
6. Protocol Specification . . . . . . . . . . . . . . . . . . . 11 6. Protocol Specification . . . . . . . . . . . . . . . . . . . 11
6.1. PIM DR Operation . . . . . . . . . . . . . . . . . . . . 11 6.1. PIM DR Operation . . . . . . . . . . . . . . . . . . . . 12
6.2. PIM GDR Candidate Operation . . . . . . . . . . . . . . . 12 6.2. PIM GDR Candidate Operation . . . . . . . . . . . . . . . 12
6.3. PIM Assert Modification . . . . . . . . . . . . . . . . . 12 6.2.1. Router receives new DRLBGDR . . . . . . . . . . . . . 13
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 6.2.2. Router receives updated DRLBGDR . . . . . . . . . . . 13
8. Security Considerations . . . . . . . . . . . . . . . . . . . 14 6.3. PIM Assert Modification . . . . . . . . . . . . . . . . . 14
9. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 14 7. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 8. Manageability Considerations . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . 14 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
10.2. Informative References . . . . . . . . . . . . . . . . . 14 10. Security Considerations . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 11. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 16
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Terminology 12.1. Normative References . . . . . . . . . . . . . . . . . . 16
12.2. Informative References . . . . . . . . . . . . . . . . . 17
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
With respect to PIM, this document follows the terminology that has
been defined in [RFC4601].
This document also introduces the following new acronyms:
o GDR: GDR stands for "Group Designated Router". For each multicast
flow, either a (*,G) for ASM, or an (S,G) for SSM, a hash
algorithm (described below) is used to select one of the routers
as a GDR. The GDR is responsible for initiating the forwarding
tree building for the corresponding multicast flow.
o GDR Candidate: a last hop router that has potential to become a
GDR. A GDR Candidate must have the same DR priority and must run
the same GDR election hash algorithm as the DR router. It must
send and process new PIM Hello Options as defined in this
document. There might be more than one GDR Candidate on a LAN.
But only one can become GDR for a specific multicast flow.
2. Introduction 1. Introduction
On a multi-access network such as an Ethernet, one of the PIM routers On a multi-access LAN such as an Ethernet, one of the PIM routers is
is elected as a DR. The PIM DR has two roles in the PIM-SM protocol. elected as a DR. The PIM DR has two roles in the PIM-SM protocol.
On the first hop network, the PIM DR is responsible for registering On the first hop network, the PIM DR is responsible for registering
an active source with the Rendezvous Point (RP) if the group is an active source with the Rendezvous Point (RP) if the group is
operating in PIM-SM. On the last hop network, the PIM DR is operating in PIM-SM. On the last hop LAN, the PIM DR is responsible
responsible for tracking local multicast listeners and forwarding to for tracking local multicast listeners and forwarding to these
these listeners if the group is operating in PIM-SM. listeners if the group is operating in PIM-SM.
Consider the following last hop network in Figure 1: Consider the following last hop LAN in Figure 1:
( core networks ) ( core networks )
| | | | | |
| | | | | |
R1 R2 R3 R1 R2 R3
| | | | | |
--(last hop LAN)-- --(last hop LAN)--
| |
| |
(many receivers) (many receivers)
Figure 1: Last Hop Network Figure 1: Last Hop LAN
Assume R1 is elected as the Designated Router. According to Assume R1 is elected as the Designated Router. According to
[RFC4601], R1 will be responsible for forwarding traffic to that LAN [RFC4601], R1 will be responsible for forwarding traffic to that LAN
on behalf of any local members. In addition to keeping track of IGMP on behalf of any local members. In addition to keeping track of IGMP
and MLD membership reports, R1 is also responsible for initiating the and MLD membership reports, R1 is also responsible for initiating the
creation of source and/or shared trees towards the senders or the creation of source and/or shared trees towards the senders or the
RPs. RPs.
Forcing sole data plane forwarding responsibility on the PIM DR Forcing sole data plane forwarding responsibility on the PIM DR
proves a limitation in the protocol. In comparison, even though an proves a limitation in the protocol. In comparison, even though an
skipping to change at page 4, line 19 skipping to change at page 4, line 5
this particular interface. These days, it is very common that the this particular interface. These days, it is very common that the
last hop LAN usually consists of switches that run IGMP/MLD or PIM last hop LAN usually consists of switches that run IGMP/MLD or PIM
snooping. This allows the forwarding of multicast packets to be snooping. This allows the forwarding of multicast packets to be
restricted only to segments leading to receivers who have indicated restricted only to segments leading to receivers who have indicated
their interest in multicast groups using either IGMP or MLD. The their interest in multicast groups using either IGMP or MLD. The
emergence of the switched Ethernet allows the aggregated bandwidth to emergence of the switched Ethernet allows the aggregated bandwidth to
exceed, some times by a large number, that of a single link. For exceed, some times by a large number, that of a single link. For
example, let us modify Figure 1 and introduce an Ethernet switch in example, let us modify Figure 1 and introduce an Ethernet switch in
Figure 2. Figure 2.
( core networks ) ( core networks )
| | | | | |
| | | | | |
R1 R2 R3 R1 R2 R3
| | | | | |
+=gi0===gi1===gi2=+ +=gi0===gi1===gi2=+
+ + + +
+ switch + + switch +
+ + + +
+=gi4===gi5===gi6=+ +=gi4===gi5===gi6=+
| | | | | |
H1 H2 H3 H1 H2 H3
Figure 2: Last Hop Network with Ethernet Switch Figure 2: Last Hop Network with Ethernet Switch
Let us assume that each individual link is a Gigabit Ethernet. Each Let us assume that each individual link is a Gigabit Ethernet. Each
router, R1, R2 and R3, and the switch have enough forwarding capacity router, R1, R2 and R3, and the switch have enough forwarding capacity
to handle hundreds of Gigabits of data. to handle hundreds of Gigabits of data.
Let us further assume that each of the hosts requests 500 Mbps of Let us further assume that each of the hosts requests 500 Mbps of
data and different traffic is requested by each host. This data and different traffic is requested by each host. This
represents a total 1.5 Gbps of data, which is under what each switch represents a total 1.5 Gbps of data, which is under what each switch
or the combined uplink bandwidth across the routers can handle, even or the combined uplink bandwidth across the routers can handle, even
under failure of a single router. under failure of a single router.
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LAN as in Figure 1). LAN as in Figure 1).
The problem may also manifest itself in a different way. For The problem may also manifest itself in a different way. For
example, R1 happens to forward 500 Mbps worth of unicast data to H1, example, R1 happens to forward 500 Mbps worth of unicast data to H1,
and at the same time, H2 and H3 each requests 300 Mbps of different and at the same time, H2 and H3 each requests 300 Mbps of different
multicast data. Once again packet drop happens on R1 while in the multicast data. Once again packet drop happens on R1 while in the
mean time, there is sufficient forwarding capacity left on R2 and R3 mean time, there is sufficient forwarding capacity left on R2 and R3
and link capacity between the switch and R2/R3. and link capacity between the switch and R2/R3.
Another important issue is related to failover. If R1 is the only Another important issue is related to failover. If R1 is the only
forwarder on the last hop network, in the event of a failure when R1 forwarder on the last hop router for shared LAN, in the event of a
goes out of service, multicast forwarding for the entire network has failure when R1 goes out of service, multicast forwarding for the
to be rebuilt by the newly elected PIM DR. However, if there was a entire LAN has to be rebuilt by the newly elected PIM DR. However,
way that allowed multiple routers to forward to the network for if there was a way that allowed multiple routers to forward to the
different groups, failure of one of the routers would only lead to LAN for different groups, failure of one of the routers would only
disruption to a subset of the flows, therefore improving the overall lead to disruption to a subset of the flows, therefore improving the
resilience of the network. overall resilience of the network.
In this document, we propose a modification to the PIM-SM protocol In this document, we propose a modification to the PIM-SM protocol
that allows more than one of these routers, called Group Designated that allows more than one of these routers, called Group Designated
Router (GDR) to be selected so that the forwarding load can be Router (GDR) to be selected so that the forwarding load can be
distributed among a number of routers. distributed among a number of routers.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119] .
With respect to PIM, this document follows the terminology that has
been defined in [RFC4601] .
This document also introduces the following new acronyms:
o GDR: GDR stands for "Group Designated Router". For each multicast
flow, either a (*,G) for ASM, or an (S,G) for SSM, a hash
algorithm (described below) is used to select one of the routers
as a GDR. The GDR is responsible for initiating the forwarding
tree building for the corresponding multicast flow.
o GDR Candidate: a last hop router that has potential to become a
GDR. A GDR Candidate must have the same DR priority and must run
the same GDR election hash algorithm as the DR router. It must
send and process new PIM Hello Options as defined in this
document. There might be more than one GDR Candidate on a LAN.
But only one can become GDR for a specific multicast flow.
3. Applicability 3. Applicability
The proposed change described in this specification applies to PIM-SM The proposed change described in this specification applies to PIM-SM
last hop routers only. last hop routers only.
It does not alter the behavior of a PIM DR on the first hop network It does not alter the behavior of a PIM DR on the first hop network
This is because the source tree is built using the IP address of the This is because the source tree is built using the IP address of the
sender, not the IP address of the PIM DR that sends the registers sender, not the IP address of the PIM DR that sends the registers
towards the RP. The load balancing between first hop routers can be towards the RP. The load balancing between first hop routers can be
achieved naturally if an IGP provides equal cost multiple paths achieved naturally if an IGP provides equal cost multiple paths
(which it usually does in practice). And distributing the load to do (which it usually does in practice). And distributing the load to do
registering does not justify the additional complexity required to registering does not justify the additional complexity required to
support it. support it.
4. Functional Overview 4. Functional Overview
In the existing PIM DR election, when multiple last hop routers are In the existing PIM DR election, when multiple last hop routers are
connected to a multi-access network (for example, an Ethernet), one connected to a multi-access LAN (for example, an Ethernet), one of
of them is selected to act as PIM DR. The PIM DR is responsible for them is selected to act as PIM DR. The PIM DR is responsible for
sending local Join/Prune messages towards the RP or source. To elect sending local Join/Prune messages towards the RP or source. To elect
the PIM DR, each PIM router on the network examines the received PIM the PIM DR, each PIM router on the LAN examines the received PIM
Hello messages and compares its DR priority and IP address with those Hello messages and compares its DR priority and IP address with those
of its neighbors. The router with the highest DR priority is the PIM of its neighbors. The router with the highest DR priority is the PIM
DR. If there are multiple such routers, their IP addresses are used DR. If there are multiple such routers, their IP addresses are used
as the tie-breaker, as described in [RFC4601]. as the tie-breaker, as described in [RFC4601].
In order to share forwarding load among last hop routers, besides the In order to share forwarding load among last hop routers, besides the
normal PIM DR election, the GDR is also elected on the last hop normal PIM DR election, the GDR is also elected on the last hop
multi-access network. There is only one PIM DR on the multi-access multi-access LAN. There is only one PIM DR on the multi-access LAN,
network, but there might be multiple GDR Candidates. but there might be multiple GDR Candidates.
For each multicast flow, that is (*,G) for ASM and (S,G) for SSM, a For each multicast flow, that is (*,G) for ASM and (S,G) for SSM, a
hash algorithm is used to select one of the routers to be the GDR. A hash algorithm is used to select one of the routers to be the GDR. A
new DR Load Balancing Capability (DRLBC) PIM Hello Option, which new DR Load Balancing Capability (DRLBC) PIM Hello Option, which
contains hash algorithm type, is announced by routers on interfaces contains hash algorithm type, is announced by routers on interfaces
where this specification is enabled. Last hop routers with the new where this specification is enabled. Last hop routers with the new
DRLBC Option advertised in its Hello, and using the same GDR election DRLBC Option advertised in its Hello, and using the same GDR election
hash algorithm and the same DR priority as the PIM DR, are considered hash algorithm and the same DR priority as the PIM DR, are considered
as GDR Candidates. as GDR Candidates.
Hash Masks are defined for Source, Group and RP separately, in order Hash Masks are defined for Source, Group and RP separately, in order
to handle PIM ASM/SSM. The masks, as well as a sorted list of GDR to handle PIM ASM/SSM. The masks, as well as a sorted list of GDR
Candidates' Addresses are announced by DR in a new DR Load Balancing Candidates' Addresses are announced by DR in a new DR Load Balancing
GDR (DRLBGDR) PIM Hello Option. GDR (DRLBGDR) PIM Hello Option.
For each multicast flow, a hash algorithm is used to select one of For each multicast flow, a hash algorithm is used to select one of
the routers to be the GDR. Hash Masks are defined for Source, Group the routers to be the GDR. The masks are announced in PIM Hello by
and RP separately, in order to handle PIM ASM/SSM. The masks are DR as a DR Load Balancing GDR (DRLBGDR) Hello Option. Besides that,
announced in PIM Hello by DR as a DR Load Balancing GDR (DRLBGDR) a DR Load Balancing Capability (DRLBC) Hello Option, which contains
Hello Option. Besides that, a DR Load Balancing Capability (DRLBC) hash algorithm type, is also announced by the router on interfaces
Hello Option, which contains hash algorithm type, is also announced where this specification is enabled. Last hop routers with the new
by the router on interfaces where this specification is enabled. DRLBC Option advertised in its Hello, and using the same GDR election
Last hop routers with the new DRLBC Option advertised in its Hello, hash algorithm and the same DR priority as the PIM DR, are considered
and using the same GDR election hash algorithm and the same DR as GDR Candidates.
priority as the PIM DR, are considered as GDR Candidates.
A hash algorithm based on the announced Source, Group or RP masks A hash algorithm based on the announced Source, Group or RP masks
allows one GDR to be assigned to a corresponding multicast state. allows one GDR to be assigned to a corresponding multicast state.
And that GDR is responsible for initiating the creation of the And that GDR is responsible for initiating the creation of the
multicast forwarding tree for multicast traffic. multicast forwarding tree for multicast traffic.
4.1. GDR Candidates 4.1. GDR Candidates
GDR is the new concept introduced by this specification. GDR GDR is the new concept introduced by this specification. GDR
Candidates are routers eligible for GDR election on the LAN. To Candidates are routers eligible for GDR election on the LAN. To
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the fourth octets. the fourth octets.
There are three Hash Masks defined, There are three Hash Masks defined,
o RP Hash Mask o RP Hash Mask
o Source Hash Mask o Source Hash Mask
o Group Hash Mask o Group Hash Mask
The Hash Masks MUST be configured on the PIM routers that can The hask masks need to be configured on the PIM routers that can
potentially become a PIM DR. potentially become a PIM DR, unless the implementation provides
default hash mask. An implementation SHOULD provide masks with
default values 255.255.255.255 (IPv4) and
FFFF:FFFF:FFFF:FFFF:FFFFF:FFFF:FFFF:FFFF (IPv6).
o If the group is ASM, and if the RP Hash Mask announced by the PIM o If the group is ASM, and if the RP Hash Mask announced by the PIM
DR is not 0, calculate the value of hashvalue_RP to determine GDR. DR is not 0, calculate the value of hashvalue_RP [Section 4.3] to
determine GDR.
o If the group is ASM and if the RP Hash Mask announced by the PIM o If the group is ASM and if the RP Hash Mask announced by the PIM
DR is 0, obtain the value of hashvalue_Group to to determine GDR. DR is 0, obtain the value of hashvalue_Group [Section 4.3 ] to
determine GDR.
o If the group is SSM, use hashvalue_SG to determine GDR. o If the group is SSM, use hashvalue_SG [Section 4.3] to determine
GDR.
A simple Modulo hash algorithm will be discussed in this document. A simple Modulo hash algorithm will be discussed in this document.
However, to allow other hash algorithm to be used, a 4-bytes "Hash However, to allow other hash algorithm to be used, a 4-bytes "Hash
Algorithm Type" field is included in DRLBC Hello Option to specify Algorithm Type" field is included in DRLBC Hello Option to specify
the hash algorithm used by a last hop router. the hash algorithm used by a last hop router.
If different hash algorithm types are advertised among last hop If different hash algorithm types are advertised among last hop
routers, only last hop routers running the same hash algorithm as the routers, only last hop routers running the same hash algorithm as the
DR (and having the same DR priority as the DR) are eligible for GDR DR (and having the same DR priority as the DR) are eligible for GDR
election. election.
4.3. Modulo Hash Algorithm 4.3. Modulo Hash Algorithm
Modulo hash algorithm is discussed here as an example, with detailed Modulo hash algorithm is discussed here as an example, with detailed
description on hashvalue_RP. description on hashvalue_RP.
For ASM groups, with a non-zero RP_hash mask, hash value is o For ASM groups, with a non-zero RP_hash mask, hash value is
calculated as: calculated as:
* hashvalue_RP = (((RP_address & RP_hashmask) >> N) & 0xFFFF) % M hashvalue_RP = (((RP_address & RP_hashmask) >> N) & 0xFFFF) % M
RP_address is the address of the RP defined for the group. N is RP_address is the address of the RP defined for the group. N
the number of zeros, counted from the least significant bit of the is the number of zeros, counted from the least significant bit
RP_hashmask. M is the number of GDR Candidates. of the RP_hashmask. M is the number of GDR Candidates.
For example, Router X with IPv4 address 203.0.113.1, receives a For example, Router X with IPv4 address 203.0.113.1, receives a
DRLBGDR Hello Option from the DR, which announces RP Hash Mask DRLBGDR Hello Option from the DR, which announces RP Hash Mask
0.0.255.0, and a list of GDR Candidates, sorted by IP addresses 0.0.255.0, and a list of GDR Candidates, sorted by IP addresses
from high to low, 203.0.113.3, 203.0.113.2 and 203.0.113.1. The from high to low, 203.0.113.3, 203.0.113.2 and 203.0.113.1.
ordinal number assigned to those addresses would be: The ordinal number assigned to those addresses would be:
0 for 203.0.113.3; 1 for 203.0.113.2; 2 for 203.0.113.1 (Router X) 0 for 203.0.113.3; 1 for 203.0.113.2; 2 for 203.0.113.1 (Router
X)
Assume there are 2 RPs: RP1 192.0.2.1 for Group1 and RP2 Assume there are 2 RPs: RP1 192.0.2.1 for Group1 and RP2
198.51.100.2 for Group2. Following the modulo hash algorithm: 198.51.100.2 for Group2. Following the modulo hash algorithm:
N is 8 for 0.0.255.0, and M is 3 for the total number of GDR N is 8 for 0.0.255.0, and M is 3 for the total number of GDR
Candidates. The hashvalue_RP for RP1 192.0.2.1 is: Candidates. The hashvalue_RP for RP1 192.0.2.1 is:
(((192.0.2.1 & 0.0.255.0) >> 8) & 0xFFFF % 3) = 2 % 3 = 2 (((192.0.2.1 & 0.0.255.0) >> 8) & 0xFFFF % 3) = 2 % 3 = 2
matches the ordinal number assigned to Router X. Router X will be matches the ordinal number assigned to Router X. Router X will
the GDR for Group1, which uses 192.0.2.1 as the RP. be the GDR for Group1, which uses 192.0.2.1 as the RP.
The hashvalue_RP for RP2 198.51.100.2 is: The hashvalue_RP for RP2 198.51.100.2 is:
(((198.51.100.2 & 0.0.255.0) >> 8) & 0xFFFF % 3) = 100 % 3 = 1 (((198.51.100.2 & 0.0.255.0) >> 8) & 0xFFFF % 3) = 100 % 3 = 1
which is different from Router X's ordinal number 2, hence, Router which is different from Router X's ordinal number 2, hence,
X will not be GDR for Group2. Router X will not be GDR for Group2.
If RP_hashmask is 0, a hash value for ASM group is calculated using o If RP_hashmask is 0, a hash value for ASM group is calculated
the group Hash Mask: using the group Hash Mask:
* hashvalue_Group = (((Group_address & Group_hashmask) >> N) & hashvalue_Group = (((Group_address & Group_hashmask) >> N) &
0xFFFF) % M 0xFFFF) % M
Compare hashvalue_Group with Ordinal number assigned to Router X, Compare hashvalue_Group with Ordinal number assigned to Router
to decide if Router X is the GDR. X, to decide if Router X is the GDR.
For SSM groups, a hash value is calculated using both the source and o For SSM groups, a hash value is calculated using both the source
group Hash Mask and group Hash Mask
* hashvalue_SG = ((((Source_address & Source_hashmask) >> N_S) & hashvalue_SG = ((((Source_address & Source_hashmask) >> N_S) &
0xFFFF) ^ (((Group_address & Group_hashmask) >> N_G) & 0xFFFF)) 0xFFFF) ^ (((Group_address & Group_hashmask) >> N_G) & 0xFFFF))
% M % M
4.4. PIM Hello Options 4.4. PIM Hello Options
When a last hop PIM router sends a PIM Hello from an interface with When a last hop PIM router sends a PIM Hello from an interface with
this specification enabled, it includes a new option, called "Load this specification enabled, it includes a new option, called "Load
Balancing Capability (DRLBC)". Balancing Capability (DRLBC)".
Besides this DRLBC Hello Option, the elected PIM DR also includes a Besides this DRLBC Hello Option, the elected PIM DR also includes a
new "DR Load Balancing GDR (DRLBGDR) Hello Option". The DRLBGDR new "DR Load Balancing GDR (DRLBGDR) Hello Option". The DRLBGDR
Hello Option consists of three Hash Masks as defined above and also Hello Option consists of three Hash Masks as defined above and also
the sorted list of all GDR Candidates' Address on the last hop the sorted list of all GDR Candidates' Address on the last hop LAN.
network.
The elected PIM DR uses DRLBC Hello Option advertised by all routers The elected PIM DR uses DRLBC Hello Option advertised by all routers
on the last hop network to compose its DRLBGDR . The GDR Candidates on the last hop LAN to compose its DRLBGDR . The GDR Candidates use
use DRLBGDR Hello Option advertised by PIM DR to calculate hash DRLBGDR Hello Option advertised by PIM DR to calculate hash value.
value.
5. Hello Option Formats 5. Hello Option Formats
5.1. PIM DR Load Balancing Capability (DRLBC) Hello Option 5.1. PIM DR Load Balancing Capability (DRLBC) Hello Option
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = TBD | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hash Algorithm Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Capability Hello Option 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = TBD | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hash Algorithm Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD. Figure 3: Capability Hello Option
Length: 4 octets Type: TBD.
Hash Algorithm Type: 0 for Modulo hash algorithm Length: 4 octets
Hash Algorithm Type: 0 for Modulo hash algorithm
This DRLBC Hello Option SHOULD be advertised by last hop routers from This DRLBC Hello Option SHOULD be advertised by last hop routers from
interfaces with this specification enabled. interfaces with this specification enabled.
5.2. PIM DR Load Balancing GDR (DRLBGDR) Hello Option 5.2. PIM DR Load Balancing GDR (DRLBGDR) Hello Option
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = TBD | Length | | Type = TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Mask | | Group Mask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Mask | | Source Mask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RP Mask | | RP Mask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GDR Candidate Address(es) | | GDR Candidate Address(es) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: GDR Hello Option
Type: TBD Figure 4: GDR Hello Option
Length: Type: TBD
Group Mask (32/128 bits): Mask Length: 3 x (4 byte or 16 byte) + n x (4 byte or 16 byte) where n
is number of GDR candidate
Group Mask (32/128 bits): Mask
Source Mask (32/128 bits): Mask Source Mask (32/128 bits): Mask
RP Mask (32/128 bits): Mask RP Mask (32/128 bits): Mask
All masks MUST be in the same address family as the Hello IP All masks MUST be in the same address family as the Hello IP
header. header.
GDR Address (32/128 bits): Address(es) of GDR Candidate(s) GDR Address (32/128 bits): Address(es) of GDR Candidate(s)
All addresses must be in the same address family as the Hello IP All addresses must be in the same address family as the Hello
header. The addresses are sorted from high to low. The order is IP header. The addresses are sorted from high to low. The
converted to the ordinal number associated with each GDR candidate order is converted to the ordinal number associated with each
in hash value calculation. For example, addresses advertised are GDR candidate in hash value calculation. For example,
R3, R2, R1, the ordinal number assigned to R3 is 0, to R2 is 1 and addresses advertised are R3, R2, R1, the ordinal number
to R1 is 2. assigned to R3 is 0, to R2 is 1 and to R1 is 2.
If "Interface ID" option, as described in [RFC6395], presents in a If "Interface ID" option, as described in [RFC6395], presents
GDR Candicate's PIM Hello message, and the "Router ID" portion is in a GDR Candicate's PIM Hello message, and the "Router ID"
non-zero, portion is non-zero,
* For IPv4, the "GDR Candidate Address" will be set directly to + For IPv4, the "GDR Candidate Address" will be set directly
"Router ID". to "Router ID".
* For IPv6, the "GDR Candidate Address" will be set to the + For IPv6, the "GDR Candidate Address" will be set to the
IPv4-IPv6 translated address of "Router ID", as described in IPv4-IPv6 translated address of "Router ID", as described in
[RFC4291], that is the "Router-ID" is appended to the prefix of [RFC4291] , that is the "Router-ID" is appended to the
96-bits zeros. prefix of 96-bits zeros.
If the "Interface ID" option is not present in a GDR Candidate's If the "Interface ID" option is not present in a GDR
PIM Hello message, or if the "Interface ID" option is present, Candidate's PIM Hello message, or if the "Interface ID" option
but"Router ID" field is zero, the "GDR Candidate Address" will be is present, but"Router ID" field is zero, the "GDR Candidate
the IPv4 or IPv6 source address from PIM Hello message. Address" will be the IPv4 or IPv6 source address from PIM Hello
message.
This DRLBGDR Hello Option SHOULD only be advertised by the elected This DRLBGDR Hello Option SHOULD only be advertised by the
PIM DR. elected PIM DR.
6. Protocol Specification 6. Protocol Specification
6.1. PIM DR Operation 6.1. PIM DR Operation
The DR election process is still the same as defined in [RFC4601]. A The DR election process is still the same as defined in [RFC4601]. A
DR that has this specification enabled on the interface, advertises DR that has this specification enabled on the interface, advertises
the new LBGRD Hello Option, which contains value of masks from user the new LBGRD Hello Option, which contains value of masks from user
configuration, followed by a sorted list of all GDR Candidates' configuration, followed by a sorted list of all GDR Candidates'
Addresses, from high to low. Moreover, same as non-DR routers, DR Addresses, from high to low. Moreover, same as non-DR routers, DR
also advertises DRLBC Hello Option to indicate its capability of also advertises DRLBC Hello Option to indicate its capability of
supporting this specification and the type of its GDR election hash supporting this specification and the type of its GDR election hash
algorithm. algorithm.
skipping to change at page 12, line 24 skipping to change at page 12, line 32
of DRLBGRD Option. of DRLBGRD Option.
6.2. PIM GDR Candidate Operation 6.2. PIM GDR Candidate Operation
When an IGMP/MLD join is received, without this proposal, only PIM DR When an IGMP/MLD join is received, without this proposal, only PIM DR
will handle the join and potentially run into the issues described will handle the join and potentially run into the issues described
earlier. Using this proposal, a hash algorithm is used on GDR earlier. Using this proposal, a hash algorithm is used on GDR
Candidate to determine which router is going to be responsible for Candidate to determine which router is going to be responsible for
building forwarding trees on behalf of the host. building forwarding trees on behalf of the host.
A router interface where this protocol is enabled advertises DRLBC A router which supports this specification, a interface where this
Hello Option in its PIM Hello, even if the router may not be protocol is enabled advertises DRLBC Hello Option in its PIM Hello,
considered as a GDR Candidate, for example, due to low DR priority. even if the router may not be considered as a GDR Candidate, for
example, due to low DR priority. once DR election is done, DRLBGDR
Hello option would be received from the current PIM DR on link.
A GDR Candidate may receive a DRLBGDR Hello Option from PIM DR, with A GDR Candidate may receive a DRLBGDR Hello Option from PIM DR, with
different Hash Masks from those configured on it, The GDR Candidate different Hash Masks from those configured on it, The GDR Candidate
must use the Hash Masks advertised by the PIM DR to calculate the must use the Hash Masks advertised by the PIM DR to calculate the
hash value. hash value.
A GDR Candidate may receive a DRLBGDR Hello Option from a PIM router A GDR Candidate may receive a DRLBGDR Hello Option from a PIM router
which is not DR. The GDR Candidate must ignore such DRLBGDR Hello which is not DR. The GDR Candidate MUST ignore such DRLBGDR Hello
Option. Option.
A GDR Candidate may receive a Hello from the elected PIM DR, and the A GDR Candidate may receive a Hello from the elected PIM DR, and the
PIM DR does not support this specification. The GDR election PIM DR does not support this specification. The GDR election
described by this specification will not take place, that is only the described by this specification will not take place, that is only the
PIM DR joins the multicast tree. PIM DR joins the multicast tree.
A router only act as GDR if it is included in the GDR list of DRLBGDR
Hello Option
6.2.1. Router receives new DRLBGDR
When a router receives new DRLBGDR from the current PIM DR, it need
to process and check if router is in list of of GDR
1. If router is not listed as a GDR candidate in DRLBGDR , no action
needed.
2. If router is listed as a GDR candidate in DRLBGDR, then it need
to process each of the groups in the IGMP/MLD reports. The masks
are announced in the PIM Hello by DR as DRLBGDR Hello option.
For each of groups in the reports it need to run hash algorithem
(described in section 4.3) based on the announced Source, Group
or RP masks to determine if it is GDR for specified group. If
hash result is to be GDR for multicast flow, it does build
multicast forwarding tree. if it is not GDR for flow, no action
is needed.
6.2.2. Router receives updated DRLBGDR
If router (GDR or non GDR) receives an unchanged DRLBGDR from the
current PIM DR, no action needed.
If router (GDR or non GDR) receives a new or modified DRLBGDR from
the current PIM DR. It requires processing as described below
1. If it was GDR and still included in current GDR list: It need to
process each of the groups, run hash algorithem to check if it is
still GDR for given group.
If it was GDR for group earlier. and even new hash choose it
as GDR, no processing required.
If it was GDR for group earlier and now it is no more GDR,
then it sets its assert metric for this flow to be
(PIM_ASSERT_INFINITY - 1), as explained in Sec 6.3
If it was not GDR for group earlier, and even new hash does
not make it GDR no processing required.
If it was not GDR earlier and now becomes GDR, it starts
building multicast forwarding tree for this flow.
2. If it was non GDR , and updated DRLBGDR from current PIM DR
contains this router as one of the GDR. In this case this router
being new GDR candiate MUST run hash algorithem for each of the
groups (multicast flows) and for given group,
If it is not GDR, no processing is required.
If it is hased as GDR , it need to build multicast forwarding
tree.
3. If a router receives IGMP/MLD report for flow for which the
router has been the GDR AND the DRLBGDR has changed since last
report for this flow, then the router MUST determine if it is
still the GDR. if it is, no action needed. if it is not, then the
router sets its assert metric for this flow to be
(PIM_ASSERT_INFINITY - 1) as explained in Sec 6.3.
6.3. PIM Assert Modification 6.3. PIM Assert Modification
It is possible that the identity of the GDR might change in the It is possible that the identity of the GDR might change in the
middle of an active flow. Examples this could happen include: middle of an active flow. Examples this could happen include:
o When a new PIM router comes up When a new PIM router comes up
When a GDR restarts
o When a GDR restarts
When the GDR changes, existing traffic might be disrupted. When the GDR changes, existing traffic might be disrupted.
Duplicates or packet loss might be observed. To illustrate the case, Duplicates or packet loss might be observed. To illustrate the case,
consider the following scenario: there are two streams G1 and G2. R1 consider the following scenario: there are two streams G1 and G2. R1
is the GDR for G1, and R2 is the GDR for G2. When R3 comes up is the GDR for G1, and R2 is the GDR for G2. When R3 comes up
online, it is possible that R3 becomes GDR for both G1 and G2, hence online, it is possible that R3 becomes GDR for both G1 and G2, hence
R3 starts to build the forwarding tree for G1 and G2. If R1 and R2 R3 starts to build the forwarding tree for G1 and G2. If R1 and R2
stop forwarding before R3 completes the process, packet loss might stop forwarding before R3 completes the process, packet loss might
occur. On the other hand, if R1 and R2 continue forwarding while R3 occur. On the other hand, if R1 and R2 continue forwarding while R3
is building the forwarding trees, duplicates might occur. is building the forwarding trees, duplicates might occur.
skipping to change at page 13, line 25 skipping to change at page 14, line 49
Here we describe a mechanism to minimize the impact. The motivation Here we describe a mechanism to minimize the impact. The motivation
is that we want to minimize packet loss. And therefore, we would is that we want to minimize packet loss. And therefore, we would
allow a small amount of duplicates and depend on PIM Assert to allow a small amount of duplicates and depend on PIM Assert to
minimize the duplication. minimize the duplication.
When the role of GDR changes as above, instead of immediately When the role of GDR changes as above, instead of immediately
stopping forwarding, R1 and R2 continue forwarding to G1 and G2 stopping forwarding, R1 and R2 continue forwarding to G1 and G2
respectively, while at the same time, R3 build forwarding trees for respectively, while at the same time, R3 build forwarding trees for
G1 and G2. This will lead to PIM Asserts. G1 and G2. This will lead to PIM Asserts.
Due to the introduction of GDR, this document suggests the following With introduction of GDR, the following modification to the Assert
modification to the Assert packet: if a router enables this packet MUST be done: if a router enables this specification on its
specification on its downstream interface, but it is not a GDR, it downstream interface, but it is not a GDR (before network event it
would adjust its Assert metric to (PIM_ASSERT_INFINITY - 1). was GDR), it would adjust its Assert metric to (PIM_ASSERT_INFINITY -
1).
Using the above example, for G1, assume R1 and R3 agree on the new Using the above example, for G1, assume R1 and R3 agree on the new
GDR, which is R3. R1 will set its Assert metric as GDR, which is R3. R1 will set its Assert metric as
(PIM_ASSERT_INFINITY - 1). That will make R3, which has normal (PIM_ASSERT_INFINITY - 1). That will make R3, which has normal
metric in its Assert as the Assert winner. metric in its Assert as the Assert winner.
For G2, assume it takes a little bit longer time for R2 to find out For G2, assume it takes a little bit longer time for R2 to find out
that R3 is the new GDR and still thinks itself being the GDR while R3 that R3 is the new GDR and still thinks itself being the GDR while R3
already has assumed the role of GDR. Since both R2 and R3 think they already has assumed the role of GDR. Since both R2 and R3 think they
are GDRs, they further compare the metric and IP address. If R3 has are GDRs, they further compare the metric and IP address. If R3 has
the better routing metric, or same metric but better tie-breaker, the the better routing metric, or same metric but better tie-breaker, the
result will be consistent with GDR selection. If unfortunately, R2 result will be consistent with GDR selection. If unfortunately, R2
has the better metric or same metric but better tie-breaker R2 will has the better metric or same metric but better tie-breaker R2 will
become the Assert winner and continues to forward traffic. This will become the Assert winner and continues to forward traffic. This will
continue until: continue until:
The next PIM Hello option from DR is seen that selects R3 as the The next PIM Hello option from DR is seen that selects R3 as the GDR.
GDR. R3 will then build the forwarding tree and send an Assert. R3 will then build the forwarding tree and send an Assert.
The process continues until R2 agrees to the selection of R3 as being The process continues until R2 agrees to the selection of R3 as being
the GDR, and set its own Assert metric to (PIM_ASSERT_INFINITY - 1), the GDR, and set its own Assert metric to (PIM_ASSERT_INFINITY - 1),
which will make R3 the Assert winner. During the process, we will which will make R3 the Assert winner. During the process, we will
see intermittent duplication of traffic but packet loss will be see intermittent duplication of traffic but packet loss will be
minimized. In the unlikely case that R2 never relinquishes its role minimized. In the unlikely case that R2 never relinquishes its role
as GDR (while every other router thinks otherwise), the proposed as GDR (while every other router thinks otherwise), the proposed
mechanism also helps to keep the duplication to a minimum until mechanism also helps to keep the duplication to a minimum until
manual intervention takes place to remedy the situation. manual intervention takes place to remedy the situation.
7. IANA Considerations 7. Compatibility
In case of hybrid Ethernet shared LAN ( where some PIM router enables
specification defined in this draft and some do not enable)
o If router which does not support specification defined in this
draft becomes DR on link, it MUST be only DR on link as [RFC4601]
and there would be no router which would act as GDR.
o If router which does not support specification defined in this
draft becomes non DR on link, then it should act as non-DR defined
in [RFC4601].
8. Manageability Considerations
o All of the router in LAN who are supporting this specification
MUST use identical Hash Algorithm Type (described in section 5.1).
In case of hybrid Hash Algorithm Type router must go backward to
use DR election method defined in PIM-SM [RFC4601]. Migration
between different algorithem type is out of scope of this
document.
9. IANA Considerations
Two new PIM Hello Option Types have been assigned to the DR Load Two new PIM Hello Option Types have been assigned to the DR Load
Balancing messages. [HELLO-OPT], this document recommends 34(0x22) Balancing messages. [HELLO-OPT], this document recommends 34(0x22)
as the new "PIM DR Load Balancing Capability Hello Option", and as the new "PIM DR Load Balancing Capability Hello Option", and
35(0x23) as the new "PIM DR Load Balancing GDR Hello Option". 35(0x23) as the new "PIM DR Load Balancing GDR Hello Option".
8. Security Considerations 10. Security Considerations
Security of the new DR Load Balancing PIM Hello Options is only Security of the new DR Load Balancing PIM Hello Options is only
guaranteed by the security of PIM Hello message, so the security guaranteed by the security of PIM Hello message, so the security
considerations for PIM Hello messages as described in PIM-SM considerations for PIM Hello messages as described in PIM-SM
[RFC4601] apply here. [RFC4601] apply here.
9. Acknowledgement 11. Acknowledgement
The authors would like to thank Steve Simlo, Taki Millonis for The authors would like to thank Steve Simlo, Taki Millonis for
helping with the original idea, Bill Atwood, Bharat Joshi for review helping with the original idea, Bill Atwood, Bharat Joshi for review
comments, Stig Venaas, Toerless Eckert and Rishabh Parekh for helpful comments, Toerless Eckert and Rishabh Parekh for helpful conversation
conversation on the document. on the document.
10. References 12. References
10.1. Normative References 12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <http://www.rfc-editor.org/info/rfc4291>.
[RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
"Protocol Independent Multicast - Sparse Mode (PIM-SM): "Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", RFC 4601, August 2006. Protocol Specification (Revised)", RFC 4601,
DOI 10.17487/RFC4601, August 2006,
<http://www.rfc-editor.org/info/rfc4601>.
[RFC6395] Gulrajani, S. and S. Venaas, "An Interface Identifier (ID) [RFC6395] Gulrajani, S. and S. Venaas, "An Interface Identifier (ID)
Hello Option for PIM", RFC 6395, October 2011. Hello Option for PIM", RFC 6395, DOI 10.17487/RFC6395,
October 2011, <http://www.rfc-editor.org/info/rfc6395>.
[RFC4291] Hinden, R. and L. S., "IP Version 6 Addressing
Architecture", RFC 6890, February 2006.
10.2. Informative References 12.2. Informative References
[HELLO-OPT] [HELLO-OPT]
IANA, , "PIM Hello Options", PIM-HELLO-OPTIONS IANA, "PIM Hello Options", IANA PIM-HELLO-OPTIONS, March
http://www.iana.org/, March 2007. 2007.
Authors' Addresses Authors' Addresses
Yiqun Cai Yiqun Cai
Microsoft Alibaba Group
La Avenida
Mountain View, CA 94043
USA
Email: yiqunc@microsoft.com Email: yiqun.cai@alibaba-inc.com
Heidi Ou
Alibaba Group
Sri Vallepalli Sri Vallepalli
Cisco Systems, Inc. Cisco Systems
Tasman Drive 3625 Cisco Way,
San Jose, CA 95134 Sanjose, CALIFORNIA 95134
USA UNITED STATES
Email: svallepa@cisco.com Email: svallepa@cisco.com
Heidi Ou Mankamana Prasad Mishra
Cisco Systems, Inc. Cisco Systems
Tasman Drive 821 Alder Drive,
San Jose, CA 95134 MILPITAS, CALIFORNIA 95035
USA UNITED STATES
Email: hou@cisco.com Email: mankamis@cisco.com
Stig Venaas
Cisco Systems
821 Alder Drive,
MILPITAS, CALIFORNIA 95035
UNITED STATES
Email: stig@cisco.com
Andy Green Andy Green
British Telecom British Telecom
Adastral Park Adastral Park
Ipswich IP5 2RE Ipswich IP5 2RE
United Kingdom United Kingdom
Email: andy.da.green@bt.com Email: andy.da.green@bt.com
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