Network Working Group                                       IJ. Wijnands
Internet-Draft                                                 S. Venaas
Intended status: Experimental                        Cisco Systems, Inc.
Expires: January 2, September 18, 2016                                      M. Brig
                                                Aegis BMD Program Office
                                                             A. Jonasson
                           Swedish Defence Material Administration (FMV)
                                                            July 1, 2015
                                                          March 17, 2016

              PIM flooding mechanism and source discovery
                 draft-ietf-pim-source-discovery-bsr-03
                 draft-ietf-pim-source-discovery-bsr-04

Abstract

   PIM Sparse-Mode uses a Rendezvous Point (RP) and shared trees to forward
   multicast packets to Last Hop Routers (LHR).  After the first
   packet is received by the LHR, the source of the multicast stream is
   learned and from new sources.  Once last hop routers receive
   packets from a new source, they may join the Shortest Path Tree (SPT) can be joined. for
   the source for optimal forwarding.  This draft
   proposes defines a solution new protcol
   that provides a way to support PIM Sparse Mode (SM) without the need
   for PIM registers, RPs or shared trees.  Multicast source information
   is flooded throughout the multicast domain using a new generic PIM
   flooding mechanism.  This mechanism is defined in this document, and
   is modeled after the PIM Bootstrap Router protocol.  By removing the
   need for RPs and shared trees, the PIM-SM procedures are simplified,
   improving router operations, management and making the protocol more
   robust. allows last hop routers to learn about new
   sources without receiving initial data packets.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on January 2, September 18, 2016.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Conventions used in this document . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Testing and deployment experiences  . . . . . . . . . . . . .   3
   3.  A generic PIM flooding mechanism  . . . . . . . . . . . . . .   4
     3.1.  PFP message format  . . . . . . . . . . . . . . . . . . .   4
     3.2.  Processing PFP messages . . . . . . . . . . . . . . . . .   6
       3.2.1.  Initial checks  . . . . . . . . . . . . . . . . . . .   6
       3.2.2.  Processing messages with known of supported PFP type . . . . . . .   6   7
       3.2.3.  Processing messages with unknown of unsupported PFP type . . . . . .   6   7
   4.  Distributing Source to Group Mappings . . . . . . . . . . . .   7
     4.1.  Group Source Holdtime TLV . . . . . . . . . . . . . . . .   7   8
     4.2.  Originating SG messages . . . . . . . . . . . . . . . . .   8
     4.3.  Processing SG messages  . . . . . . . . . . . . . . . . .   8   9
     4.4.  The first packets and bursty sources  . . . . . . . . . .   9
     4.5.  Resiliency to network partitioning  . . . . . . . . . . .  10
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10  11
   6.  IANA considerations . . . . . . . . . . . . . . . . . . . . .  10  11
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  10  11
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  11  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11  12

1.  Introduction

   PIM Sparse-Mode uses a Rendezvous Point (RP) and shared trees to
   forward multicast packets to Last Hop Routers (LHR).  After the first
   packet is received by the a LHR, the source of the multicast stream is
   learned and the Shortest Path Tree (SPT) can be joined.  This draft
   proposes
   defines a solution new protocol that provides a way to support PIM Sparse Mode
   (SM) without the need for PIM registers, RPs or shared trees.
   Multicast source information is flooded throughout the multicast
   domain using a new generic PIM flooding mechanism.  This mechanism is
   defined in this document, and is modeled after the Bootstrap Router
   protocol [RFC5059].  By removing the need for RPs and shared trees,
   the PIM-SM procedures are simplified, improving router operations,
   management and making the protocol more robust.  Also the data
   packets are only sent on the SPTs, providing optimal forwarding.

1.1.  Conventions used in this document

   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 RFC 2119 [RFC2119].

1.2.  Terminology

   RP:  Rendezvous Point.

   BSR:  Bootstrap Router.

   RPF:  Reverse Path Forwarding.

   SPT:  Shortest Path Tree.

   FHR:  First Hop Router, directly connected to the source.

   LHR:  Last Hop Router, directly connected to the receiver.

   SG Mapping:  Multicast source to group mapping.

   SG Message:  A PIM message containing SG Mappings.

2.  Testing and deployment experiences

   A prototype of this specification has been implemented and there has
   been some limited testing in the field.  The prototype was tested in
   a network with low bandwidth radio links.  In this network with
   frequent topology changes and link or router failures PIM-SM with RP
   election is found to be too slow.  With PIM-DM issues were observed
   with new multicast sources starving low bandwidth links even when
   there are no receivers, in some cases such that there were no
   bandwidth left for prune message.  For the tests, all routers were
   configured to send PFP-SA for directly connected source and to cache
   received announcements.  Applications such as SIP with multicast
   subscriber discovery, multicast voice conferencing, position tracking
   and NTP were successfully tested.  The tests went quite well.
   Packets were rerouted as needed and there were no unnecessary
   forwarding of packets.  Ease of configuration was seen as a plus.

3.  A generic PIM flooding mechanism

   The Bootstrap Router protocol (BSR) [RFC5059] is a commonly used
   protocol for distributing dynamic Group to RP mappings in PIM.  It is
   responsible for flooding information about such mappings throughout a
   PIM domain, so that all routers in the domain can have the same
   information.  BSR as defined, is only able to distribute Group to RP
   mappings.  We are defining a more generic mechanism that can flood
   any kind of information throughout a PIM domain.  It is not
   necessarily a domain though, it depends on the administrative
   boundaries being configured.  The forwarding rules are identical to
   BSR, except that there is no BSR election and that one can control
   whether routers should forward messages of unsupported types.  For
   some types of information it is quite useful that it can be
   distributed without all routers having to support the particular
   type, while there may also be types where it is necessary for every
   single router to support it.  The protocol includes an originator
   address which is used for RPF checking to restrict the flooding, just
   like BSR.  Just like BSR it is also sent hop by hop.  Note that there
   is no built in election mechanism as in BSR, so there can be multiple
   originators.  It is still possible to add such an election mechanism
   on a type by type bases if this protocol is used in scenarios where
   this is desirable.  We include a type field, which can allow
   boundaries to be defined, and election to take place, independently
   per type.  We call this protocol the PIM Flooding Protocol (PFP).

3.1.  PFP message format
        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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |PIM Ver| Type  |N|  Reserved   |           Checksum            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Originator Address (Encoded-Unicast format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            PFP Type           |         Reserved            |U|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Type 1               |          Length 1             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                            Value 1                            |
      |                               .                               |
      |                               .                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                               .                               |
      |                               .                               |
      |          Type n               |          Length n             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                            Value n                            |
      |                               .                               |
      |                               .                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   PIM Version:   Reserved, Checksum Described in [RFC4601]. [RFC7761].

   Type:   PIM Message Type.  Value (pending IANA) for a PFP message.

   [N]o-Forward bit:   When set, this bit means that the PFP message is
      not to be forwarded.  This is irrespective of the value of the
      Unsupported-No-Forwarding bit defined below.

   Originator Address:   The address of the router that originated the
      message.  This can be any address assigned to this the originating
      router, but MUST be routable in the domain to allow successful
      forwarding (just like BSR address).  The format for this address
      is given in the Encoded-Unicast address in [RFC4601]. [RFC7761].

   PFP Type:   There may be different sub protocols or different uses
      for this generic protocol.  The PFP Type specifies which sub
      protocol it is used for.

   [U]nknown-No-Forwarding

   [U]nsupported-No-Forwarding bit:   When the No-Forward bit defined
      above is not set, whether to forward the message depends on
      whether the PFP type is supported and the setting of the
      Unsupported-No-Forwarding bit.  Some sub protocols may require
      that each router do some processing of the contents and not simply
      forwarding.  This bit controls how a router should treat an
      unknown PFP Type.
      forward the message.  When Unsupported-No-Forwarding bit is set, a
      router MUST NOT forward the message when the PFP Type is unknown.
      unsupported.  When clear, it is not set, a router MUST forward the
      message when possible.  If the PFP Type is known, supported, then the
      specification of that type will specify how to handle the message,
      including whether it the message should be forwarded.

   Type 1..n:   A message contains one or more TLVs, in this case n
      TLVs.  The Type specifies what kind of information is in the
      Value.  Note that the Type space is shared between all PFP types.
      Not all types make sense for all PFP types though.

   Length 1..n:   The length of the the value field.

   Value 1..n:   The value associated with the type and of the specified
      length.

3.2.  Processing PFP messages

   A router that receives an PFP message must MUST perform the initial checks
   specified here.  If it passes, the checks fail, the message MUST be dropped.  An
   error MAY be logged, but otherwise the message MUST be dropped
   silently.  If the checks pass, the contents is processed according to
   the PFP type if known. supported.  If the type is unknown unsupported it may still
   be
   forwarded. forwarded if neither the No-Forward bit nor the Unsupported-No-
   Forwarding bit are set.

3.2.1.  Initial checks

   The initial checks performed are largely similar

   In order to what is done for
   BSR messages. do further processing, a message MUST meet the following
   requirements.  The message MUST be from a directly connected neighbor
   for which we have active Hello state.  It state, and it MUST have been sent to
   the ALL-PIM-ROUTERS group, and unless group.  Also, the interface MUST NOT be an
   administrative boundary for the message's PFP type.  If No-Forward is
   not set, it MUST have been sent by the RPF neighbor towards the
   router that originated the
   message; or, if it is a message.  If No-Forward BSM, is set, we must MUST
   have restarted within 60 seconds.  In pseudo-code the algorithm is as
   follows:

              if ((DirectlyConnected(PFP.src_ip_address) == FALSE) OR
                  (we have no Hello state for PFP.src_ip_address) OR
                  (PFP.dst_ip_address != ALL-PIM-ROUTERS) OR
                  (Incoming interface is admin boundary for PFP.type)) {
                   drop the message silently, optionally log error.
              }
              if (PFP.no_forward_bit == 0) {
                  if (PFP.src_ip_address !=
                      RPF_neighbor(PFP.originator_ip_address)) {
                      drop the message silently, optionally log error.
                  }
              } else if (more than 60 seconds elapsed since startup)) {
                  drop the message silently, optionally log error.
              }

3.2.2.  Processing messages with known of supported PFP type

   When the message is received, the initial checks above must be
   performed.  If it passes the checks, then we continue as follows.  If
   the PFP type is known, as in supported by the implementation, the processing and
   potential forwarding is done according to the specification for that
   PFP type.  If the PFP type specification does not specify any
   particular forwarding rules, the message is forwarded out of all
   interfaces with PIM neighbors (including the interface it
   is was
   received on).

3.2.3.  Processing messages with unknown of unsupported PFP type

   When the message is received, the initial checks above must be
   performed.  If it passes the checks, then we continue as follows.  If
   the PFP type is unknown, unsupported, the message MUST be dropped if the
   Unknown-No-Forwarding
   Unsupported-No-Forwarding bit is set.  If the bit is not set, the
   message is forwarded out of all interfaces with PIM neighbors
   (including the interface it is was received on).

4.  Distributing Source to Group Mappings

   We want to provide information about active multicast sources
   throughout a PIM domain by making use of the generic flooding
   mechanism defined in the previous section.  We request PFP Type 0 to
   be assigned for this purpose.  We call a message with PFP Type 0 an
   SG Message.  We also define a PFP TLV which we request to be type 0.
   How this TLV is used with PFP Type 0 is defined in the next section.
   Other PFP Types may specify the use of this TLV for other purposes.
   For PFP Type 0 the U-bit MUST NOT be set.  This means that routers
   not supporting PFP Type 0 would still forward the message.

4.1.  Group Source Holdtime TLV

        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 = 0               |          Length             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              Group Address (Encoded-Group format)             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Src Count          |        Src Holdtime           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Src Address 1 (Encoded-Unicast format)             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Src Address 2 (Encoded-Unicast format)             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                               .                               |
      |                               .                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Src Address m (Encoded-Unicast format)             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type:   This TLV has type 0.

   Length:   The length of the value.

   Group Address:   The group we are announcing sources for.  The format
      for this address is given in the Encoded-Group format in
      [RFC4601].
      [RFC7761].

   Src Count:   How many unicast encoded sources address encodings
      follow.

   Src Holdtime:   The Holdtime (in seconds) for the corresponding
      source(s).

   Src Address:   The source address for the corresponding group.  The
      format for these addresses is given in the Encoded-Unicast address
      in [RFC4601]. [RFC7761].

4.2.  Originating SG messages

   An SG Mesage, Message, that is a PFP message of Type 0, may MAY contain one or
   more Group Source Holdtime TLVs.  This is used to flood information
   about active multicast sources.  Each FHR that is directly connected
   to an active multicast source originates SG BSR messages.  How a
   multicast router discovers the source of the multicast packet and
   when it considers itself the FHR follows the same procedures as the
   registering process described in [RFC4601].  After it is [RFC7761].  When a FHR has decided
   that a register needs to be sent, sent per [RFC7761], the SG is not
   registered via the PIM SM register procedures, but the SG mapping is
   included in an SG message.  Note, only the SG mapping is distributed
   in the message, not the entire packet as would have been done with a
   PIM register.  The router originating the SG messages includes one of
   its own addresses in the originator field.  Note that this address must
   SHOULD be routeable due to RPF checking.  The SG messages are
   periodically sent for as long as the multicast source is active,
   similar to how PIM registers are periodically sent.  The default
   announcement period is 60 seconds, which means that as long as the
   source is active, it is included in an SG message originated every 60
   seconds.  The holdtime for the source is by default 210 seconds.
   Other values can MAY be configured, but the holdtime must MUST be either zero,
   or larger than the announcement period.  It is RECOMMENDED to be 3.5
   times the announcement period.
   Note that as a special case a  A source MAY be announced with a
   holdtime of 0 zero to indicate that the source is no longer active.

4.3.  Processing SG messages

   A router that receives an SG message should SHOULD parse the message and
   store the SG mappings with a holdtimer started with the advertised
   holdtime for that group.  If there are  For each group that has directly connected receivers
   for that group
   receivers, this router should SHOULD send PIM (S,G) joins for all the SG
   mappings advertised in the message. message for the group.  The SG mappings
   are kept alive for as long as the holdtimer for the source is
   running.  Once the holdtimer expires a PIM router SHOULD send a PIM
   (S,G) prune to remove itself from the tree.  Note that a holdtime of 0
   zero has a special meaning.  It is to be treated as if the source
   just expired, causing a prune to be sent and state to be removed.
   Source information MUST
   not NOT be removed due to it being omitted in a
   message.  For instance, if there are a large number of sources for a
   group, there may be multiple SG messages for the same group, each
   message containing a different list of sources.

4.4.  The first packets and bursty sources

   The PIM register procedure is designed to deliver Multicast packets
   to the RP in the absence of a native SPT tree Shortest Path Tree (SPT) from the RP to
   the source.  The register packets received on the RP are decapsulated
   and forwarded down the shared tree to the LHRs.  As soon as an SPT tree is
   built, multicast packets would flow natively over the SPT to the RP
   or LHR and the register process would stop.  The PIM register process
   ensures packet delivery until an SPT tree is in place reaching the FHR.
   If the packets were not unicast encapsulated to the RP they would be
   dropped by the FHR until the SPT is setup.  This functionality is
   important for applications where the initial packet(s) must be
   received for the application to work correctly.  Another reason would
   be for bursty sources.  If the application sends out a multicast
   packet every 4 minutes (or longer), the SPT is torn down (typically
   after 3:30 minutes of inactivity) before the next packet is forwarded
   down the tree.  This will cause no multicast packet to ever be
   forwarded.  A well behaved application should
   really be able to deal with
   packet loss since IP is a best effort based packet delivery system.
   But in reality this is not always the case.

   With the procedures proposed defined in this draft document the packet(s) received
   by the FHR will be dropped until the LHR has learned about the source
   and the SPT tree is built.  That means for bursty sources or applications
   sensitive for the delivery of the first packet this
   proposal solution would
   not be very applicable.  This proposal solution is mostly useful for
   applications that don't have strong dependency on the initial
   packet(s) and have a fairly constant data rate, like video
   distribution for example.  For applications with strong dependency on
   the initial packet(s) we recommend using PIM Bidir [RFC5015] or SSM
   [RFC4607].  The protocol operations are much simpler compared to PIM
   SM, it will cause less churn in the network and both guarantee best
   effort delivery for the initial packet(s).

   Another solution to address the problems described above is
   documented in [I-D.ietf-magma-msnip].  This proposal allows for a
   host to tell the FHR its willingness to act as Source for a certain
   Group before sending the data packets.  LHRs have time to join the
   SPT tree before the host starts sending which would avoid packet loss.
   The SG mappings announced by [I-D.ietf-magma-msnip] can be advertised
   directly in SG messages, allowing a very nice integration of both
   proposals.  The life time of the SPT is not driven by the liveliness
   of Multicast data packets (which is the case with PIM SM), but by the
   announcements driven via [I-D.ietf-magma-msnip].  This will also
   prevent packet loss due to bursty sources.

4.5.  Resiliency to network partitioning

   In a PIM SM deployment where the network becomes partitioned, due to
   link or node failure, it is possible that the RP becomes unreachable
   to a certain part of the network.  New sources that become active in
   that partition will not be able to register to the RP and receivers
   within that partition are not able to receive the traffic.  Ideally
   you would want to have a candidate RP in each partition, but you
   never know in advance which routers will form a partitioned network.
   In order to be fully resilient, each router in the network may end up
   being a candidate RP.  This would increase the operational complexity
   of the network.

   The solution described in this document does not suffer from that
   problem.  If a network becomes partitioned and new sources become
   active, the receivers in that partitioned will receive the SG
   Mappings and join the source tree.  Each partition works
   independently of the other partition(s) and will continue to have
   access to sources within that partition.  As soon as the network
   heals, the SG Mappings are re-flooded into the other partition(s) and
   other receivers can join to the newly learned sources.

5.  Security Considerations

   The security considerations are mainly similar to what is documented
   in [RFC5059].  It may be is a concern that rogue devices can inject packets
   that are flooded throughout a domain.  PFP packets SHOULD must only be
   accepted from a PIM neighbor.  Deployments may use mechanisms for
   authenticating PIM neighbors.  For PFP-SA it is an issue that
   injected packets from a rogue device could send SG mappings for a
   large number of source addresses, causing routers to use memory
   storing these mappings, and also if they have interest in the groups,
   build Shortest Path Trees for sources that are not actually active.

6.  IANA considerations

   This document requires the assignment of a new PIM Protocol type for
   the PIM Flooding Protocol (PFP).  IANA is also requested to create a
   registry for PFP Types with type 0 allocated assigned to "Source-Group
   Message".  IANA is also requested to create a registry for PFP TLVs,
   with type 0 allocated assigned to the "Source Group Holdtime" TLV.  The
   allocation procedures  Assignments
   for both registries are yet to be determined. made according to the policy "IETF
   Review" as defined in [RFC5226].

7.  Acknowledgments

   The authors would like to thank Arjen Boers for contributing to the
   initial idea and Yiqun Cai for his comments on the draft.

8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997.

   [RFC4601]  Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
              "Protocol Independent Multicast - Sparse Mode (PIM-SM):
              Protocol Specification (Revised)", RFC 4601, August 2006. 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC5059]  Bhaskar, N., Gall, A., Lingard, J., and S. Venaas,
              "Bootstrap Router (BSR) Mechanism for Protocol Independent
              Multicast (PIM)", RFC 5059, DOI 10.17487/RFC5059, January 2008.
              2008, <http://www.rfc-editor.org/info/rfc5059>.

   [RFC7761]  Fenner, B., Handley, M., Holbrook, H., Kouvelas, I.,
              Parekh, R., Zhang, Z., and L. Zheng, "Protocol Independent
              Multicast - Sparse Mode (PIM-SM): Protocol Specification
              (Revised)", STD 83, RFC 7761, DOI 10.17487/RFC7761, March
              2016, <http://www.rfc-editor.org/info/rfc7761>.

8.2.  Informative References

   [RFC4607]  Holbrook, H. and B. Cain, "Source-Specific Multicast for
              IP", RFC 4607, DOI 10.17487/RFC4607, August 2006. 2006,
              <http://www.rfc-editor.org/info/rfc4607>.

   [RFC5015]  Handley, M., Kouvelas, I., Speakman, T., and L. Vicisano,
              "Bidirectional Protocol Independent Multicast (BIDIR-
              PIM)", RFC 5015, DOI 10.17487/RFC5015, October 2007. 2007,
              <http://www.rfc-editor.org/info/rfc5015>.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              DOI 10.17487/RFC5226, May 2008,
              <http://www.rfc-editor.org/info/rfc5226>.

   [I-D.ietf-magma-msnip]
              Fenner, B., Haberman, B., Holbrook, H., Kouvelas, I., and
              S. Venaas, "Multicast Source Notification of Interest
              Protocol (MSNIP)", draft-ietf-magma-msnip-06 (work in
              progress), March 2011.

Authors' Addresses

   IJsbrand Wijnands
   Cisco Systems, Inc.
   De kleetlaan 6a
   Diegem  1831
   Belgium

   Email: ice@cisco.com

   Stig Venaas
   Cisco Systems, Inc.
   Tasman Drive
   San Jose  CA  95134
   USA

   Email: stig@cisco.com
   Michael Brig
   Aegis BMD Program Office
   17211 Avenue D, Suite 160
   Dahlgren  VA 22448-5148
   USA

   Email: michael.brig@mda.mil

   Anders Jonasson
   Swedish Defence Material Administration (FMV)
   Loennvaegen 4
   Vaexjoe  35243
   Sweden

   Email: anders@jomac.se