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rfc:rfc4602

Network Working Group T. Pusateri Request for Comments: 4602 Juniper Networks Category: Informational August 2006

       Protocol Independent Multicast - Sparse Mode (PIM-SM)
            IETF Proposed Standard Requirements Analysis

Status of This Memo

 This memo provides information for the Internet community.  It does
 not specify an Internet standard of any kind.  Distribution of this
 memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (2006).

Abstract

 This document provides supporting documentation to advance the
 Protocol Independent Multicast - Sparse Mode (PIM-SM) routing
 protocol from IETF Experimental status to Proposed Standard.

Table of Contents

 1. Introduction ....................................................2
 2. RFC 1264 Requirements ...........................................2
    2.1. Documents Specifying the Protocol and Its Usage ............2
    2.2. Management Information Base ................................2
    2.3. Explicit Security Architecture .............................2
    2.4. Implementation Existence ...................................3
         2.4.1. XORP ................................................3
         2.4.2. Cisco IOS/IOX .......................................3
         2.4.3. Infosys Technologies, Ltd. ..........................3
         2.4.4. Procket Networks ....................................3
    2.5. Evidence of Testing ........................................4
         2.5.1. Cisco ...............................................4
         2.5.2. XORP ................................................4
         2.5.3. Procket Networks ....................................5
    2.6. Suitability ................................................5
    2.7. Authentication Mechanisms ..................................5
 3. Security Considerations .........................................5
 4. Acknowledgements ................................................5
 5. References ......................................................6
    5.1. Normative References .......................................6
    5.2. Informative References .....................................6

Pusateri Informational [Page 1] RFC 4602 PIM-SM Proposed Standard Req. Analysis August 2006

1. Introduction

 This analysis provides supporting documentation to advance the
 Protocol Independent Multicast - Sparse Mode (PIM-SM) routing
 protocol from the IETF Experimental status to Proposed Standard.
 PIM-SM was first published as RFC 2117 [RFC2117] in 1997 and then
 again as RFC 2362 [RFC2362] in 1998.  The protocol was classified as
 Experimental in both of these documents.  The PIM-SM protocol
 specification was then rewritten in whole in order to more fully
 specify the protocol.  It is this new specification that is to be
 advanced to Proposed Standard.

2. RFC 1264 Requirements

 Section 4.0 of RFC 1264 [RFC1264] describes the requirements for
 routing protocols to advance to Proposed Standard.  Each requirement
 is listed below along with an explanation of how the requirement has
 been satisfied.

2.1. Documents Specifying the Protocol and Its Usage

 The authors of the new PIM-SM specification [RFC4601] have taken
 considerable care to fully specify the protocol operation.  It
 removes all known ambiguities and tries to normalize corner cases
 that existed in the previous specification.  It has been used to
 provide several interoperable implementations by developers that were
 not authors of the specification.  These implementations will be
 described below.

2.2. Management Information Base

 A Management Information Base for PIM is currently specified in RFC
 2934 [RFC2934].  This MIB has many implementations and has been used
 by network management applications for several years.  Updates to
 this MIB to support IPv6 and other improvements based on operation
 experience are in progress in the PIM Working Group of the IETF.

2.3. Explicit Security Architecture

 The new PIM Sparse-Mode protocol specification contains an extensive
 security section explaining its security features and limitations.
 Data integrity protection and groupwise data origin authentication is
 provided for PIM protocol messages.

Pusateri Informational [Page 2] RFC 4602 PIM-SM Proposed Standard Req. Analysis August 2006

2.4. Implementation Existence

 There are at least 4 known independent implementations of the new
 protocol specification, and there are over 6 independent
 implementations of a previous version (RFC 2362) of the
 specification.  The new specification was carefully written to be
 backward compatible with the old specification allowing
 implementations compliant with RFC 2362 to also be compliant with the
 new specification.
 The 4 implementations of the new version are described below.

2.4.1. XORP

 The XORP project [XORP] has an open-source implementation of PIM-SM
 v2 as specified in RFC 4601.  It was written by Pavlin Radoslavov
 <pavlin@icir.org> and has been available to the public since December
 2002.  Pavlin is not an author of the protocol specification.  It
 does not use any other existing code as a base.

2.4.2. Cisco IOS/IOX

 Cisco Systems, Inc., has written an implementation of the new
 protocol specification that has been deployed in production routers.
 There exists an IOS implementation for IPv6 only.  There exists an
 IOX implementation for both IPv4 and IPv6.  This code was initially
 written by Isidor Kouvelas <kouvelas@cisco.com>.  It does not depend
 on any existing code base.  Isidor is a co-author of the protocol
 specification.

2.4.3. Infosys Technologies, Ltd.

 Infosys Technologies, Ltd. (www.infosys.com), has developed a limited
 shared-tree implementation of the new Sparse-Mode specification
 including PIM Hello messages, DR election, PIM join/prune messages,
 join suppression, and prune override.  It was written by Bharat Joshi
 <bharat_joshi@infosys.com> and is used in commercial products.
 Bharat is not an author of the protocol specification.

2.4.4. Procket Networks

 An implementation was written from scratch at Procket Networks by
 Dino Farinacci <dino@cisco.com>.  This implementation is now owned by
 Cisco Systems, Inc.  Dino is not an author of the new protocol
 specification.

Pusateri Informational [Page 3] RFC 4602 PIM-SM Proposed Standard Req. Analysis August 2006

2.5. Evidence of Testing

2.5.1. Cisco

 The Cisco implementation has undergone extensive laboratory testing
 as well as testing in production deployments.  It is found to
 interoperate with implementations of earlier versions of the PIM
 Sparse-Mode protocol specification.

2.5.2. XORP

 The XORP PIM-SM implementation has been thoughtfully tested
 internally by the XORP project.  The emphasis during testing has been
 on correctness.  In a typical setup, a PIM-SM router's behavior is
 tested by connecting it to external packet generators and observers.
 The packet generators are used to generate messages such as IGMP and
 PIM-SM control packets, and multicast data packets.  The packet
 observers are used to observe the PIM-SM control packets generated by
 the PIM-SM router under test, and to observe the data packets that
 may be forwarded by that router.  In addition, the router's command-
 line interface has been used to observe its internal state during
 some of the tests.
 The test scenarios have been designed to follow the protocol
 specification closely (e.g., a separate test has been created for
 each event in the various protocol state machines, etc).  All test
 scenarios are described in detail in the XORP PIM-SM Test Suite
 [XORP-TEST].
 The major tested features are:
 1.  Multicast data forwarding.
 2.  PIM Hello messages exchange, PIM router neighbor discovery,
     option exchange, and DR election.
 3.  PIM Register messages transmission and reception, PIM Register
     state machine, and multicast data packets encapsulation and
     decapsulation.
 4.  Transmission and reception of PIM Join/Prune messages and
     upstream and downstream protocol state machines.  The tests
     consider the following state: (*,*,RP), (*,G), (S,G), and
     (S,G,rpt).
 5.  Transmission and reception of PIM Assert messages and the per-
     interface (*,G) and (S,G) Assert state machines.

Pusateri Informational [Page 4] RFC 4602 PIM-SM Proposed Standard Req. Analysis August 2006

 6.  PIM Bootstrap mechanism: transmission, reception, and forwarding
     of PIM Bootstrap messages (BSMs), transmission and reception of
     PIM Cand-RP-Adv messages, candidate and non-candidate Bootstrap
     Router (BSR) state machines, creating the RP-Set at the BSR,
     receiving and using the RP-Set, and semantic fragmentation of
     BSMs.
 In the final tests, the tested router behaved as specified in the
 PIM-SM protocol specification.  All issues found in the protocol
 specification itself have been corrected in earlier versions of the
 document.

2.5.3. Procket Networks

 The Procket Networks implementation was deployed in many research and
 service provider networks and showed interoperability with new and
 old Cisco Systems implementations as well as Juniper Networks
 implementations.

2.6. Suitability

 PIM Sparse-Mode is a protocol for efficiently routing multicast
 groups that may span wide-area (and inter-domain) Internets.  PIM
 uses the underlying unicast routing to provide reverse-path
 information for multicast tree building, but it is not dependent on
 any particular unicast routing protocol.

2.7. Authentication Mechanisms

 PIM specifies the use of the IP security (IPsec) authentication
 header (AH) to provide data integrity protection and groupwise data
 origin authentication of protocol messages.  The specific AH
 authentication algorithm and parameters, including the choice of
 authentication algorithm and the choice of key, are configured by the
 network administrator.  The threats associated with receiving forged
 PIM messages are outlined in the security considerations section of
 the protocol specification.

3. Security Considerations

 No considerations apply to a requirements analysis about a routing
 protocol, only to a specification for that routing protocol.

4. Acknowledgements

 Pavlin Radoslavov provided text for the section on XORP testing.
 Dino Farinacci provided text for the Procket Networks testing.

Pusateri Informational [Page 5] RFC 4602 PIM-SM Proposed Standard Req. Analysis August 2006

5. References

5.1. Normative References

 [RFC2934]   McCloghrie, K., Farinacci, D., Thaler, D., and B. Fenner,
             "Protocol Independent Multicast MIB for IPv4", RFC 2934,
             October 2000.
 [RFC4601]   Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
             "Protocol Independent Multicast - Sparse Mode (PIM-SM):
             Protocol Specification (Revised)", RFC 4601, August 2006.

5.2. Informative References

 [RFC1264]   Hinden, R., "Internet Engineering Task Force Internet
             Routing Protocol Standardization Criteria", RFC 1264,
             October 1991.
 [RFC2117]   Estrin, D., Farinacci, D., Helmy, A., Thaler, D.,
             Deering, S., Handley, M., Jacobson, V., Liu, C., Sharma,
             P., and L. Wei, "Protocol Independent Multicast-Sparse
             Mode (PIM-SM): Protocol Specification", RFC 2117, June
             1997.
 [RFC2362]   Estrin, D., Farinacci, D., Helmy, A., Thaler, D.,
             Deering, S., Handley, M., Jacobson, V., Liu, C., Sharma,
             P., and L. Wei, "Protocol Independent Multicast-Sparse
             Mode (PIM-SM): Protocol Specification", RFC 2362, June
             1998.
 [XORP]      "XORP Project", <http://www.xorp.org>.
 [XORP-TEST] "XORP PIM-SM Test Suite", <http://www.xorp.org/releases/
             current/docs/pim_testsuite/pim_testsuite.pdf>.

Pusateri Informational [Page 6] RFC 4602 PIM-SM Proposed Standard Req. Analysis August 2006

Author's Address

 Tom Pusateri
 Juniper Networks
 1194 North Mathilda Avenue
 Sunnyvale, CA  94089
 USA
 Phone: +1 408 745 2000
 EMail: pusateri@juniper.net

Pusateri Informational [Page 7] RFC 4602 PIM-SM Proposed Standard Req. Analysis August 2006

Full Copyright Statement

 Copyright (C) The Internet Society (2006).
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 contained in BCP 78, and except as set forth therein, the authors
 retain all their rights.
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Acknowledgement

 Funding for the RFC Editor function is provided by the IETF
 Administrative Support Activity (IASA).

Pusateri Informational [Page 8]

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