draft-ietf-pim-join-attributes-01.txt   draft-ietf-pim-join-attributes-02.txt 
PIM WG A. Boers PIM WG A. Boers
Internet-Draft IJ. Wijnands Internet-Draft IJ. Wijnands
Expires: September 2, 2006 E. Rosen Intended status: Informational E. Rosen
Cisco Systems, Inc. Expires: April 26, 2007 Cisco Systems, Inc.
march 2006 October 23, 2006
Format for using TLVs in PIM messages Format for using TLVs in PIM messages
draft-ietf-pim-join-attributes-01 draft-ietf-pim-join-attributes-02
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
skipping to change at page 1, line 35 skipping to change at page 1, line 35
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."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on September 2, 2006. This Internet-Draft will expire on April 26, 2007.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The Internet Society (2006).
Abstract Abstract
This document describes a generic TLV attribute encoding format to be This document describes a generic TLV attribute encoding format to be
added to PIM join messages. added to PIM join messages.
Table of Contents Table of Contents
1. Conventions used in this document . . . . . . . . . . . . . . . 3 1. Conventions used in this document . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Use of the Attribute Field in Join Messages . . . . . . . . . . 3 3. Use of the Attribute Field in Join Messages . . . . . . . . . . 3
3.1. Attribute join . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Attribute join . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Transitive attributes . . . . . . . . . . . . . . . . . . . 3 3.2. Transitive attributes . . . . . . . . . . . . . . . . . . . 3
3.3. Attribute Hello Option . . . . . . . . . . . . . . . . . . 3 3.3. Attribute Hello Option . . . . . . . . . . . . . . . . . . 3
3.4. Conflicting attributes . . . . . . . . . . . . . . . . . . 4 3.4. Conflicting attributes . . . . . . . . . . . . . . . . . . 4
3.5. Attribute Convergence . . . . . . . . . . . . . . . . . . . 4 3.5. Attribute Convergence . . . . . . . . . . . . . . . . . . . 5
3.6. Multiple attributes . . . . . . . . . . . . . . . . . . . . 5 3.6. Multiple attributes . . . . . . . . . . . . . . . . . . . . 5
3.7. Applicability of the attributes . . . . . . . . . . . . . . 5 3.7. Applicability of the attributes . . . . . . . . . . . . . . 5
3.8. PIM attribute packet format . . . . . . . . . . . . . . . . 5 3.8. PIM attribute packet format . . . . . . . . . . . . . . . . 5
3.8.1. PIM Join packet format . . . . . . . . . . . . . . . . 5 3.8.1. PIM Join packet format . . . . . . . . . . . . . . . . 5
3.8.2. PIM Attribute Hello option . . . . . . . . . . . . . . 6 3.8.2. PIM Attribute Hello option . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 6 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References . . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . . 7 7.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
Intellectual Property and Copyright Statements . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . . . . 9
1. Conventions used in this document 1. Conventions used in this document
In this document, the key words "MUST", "MUST NOT", "REQUIRED", In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in RFC 2119 and and "OPTIONAL" are to be interpreted as described in RFC 2119 and
indicate requirement levels for compliant PIM-SM implementations. indicate requirement levels for compliant PIM-SM implementations.
2. Introduction 2. Introduction
skipping to change at page 3, line 26 skipping to change at page 3, line 26
do this. This document defines a new field in the PIM Join message do this. This document defines a new field in the PIM Join message
that allows it to use TLVs, hereby called the attribute field. The that allows it to use TLVs, hereby called the attribute field. The
content and purpose of this attribute field is outside the scope of content and purpose of this attribute field is outside the scope of
this document, only the generic encoding format is described here. this document, only the generic encoding format is described here.
3. Use of the Attribute Field in Join Messages 3. Use of the Attribute Field in Join Messages
3.1. Attribute join 3.1. Attribute join
Attribute fields are defined similar to the PIM source encoding type Attribute fields are defined similar to the PIM source encoding type
as defined in [I-D.ietf-pim-sm-v2-new]. A source address without any as defined in [RFC4601]. A source address without any additional
additional TLV's should be processed identically to a source address TLV's should be processed identically to a source address in the
in the default source encoding. default source encoding.
Multiple TLV's from the same or different type are permitted in a Multiple TLV's from the same or different type are permitted in a
single source address in any order. single source address in any order.
3.2. Transitive attributes 3.2. Transitive attributes
It may be desired to have routers that understand the generic It may be desired to have routers that understand the generic
attribute format, forward the attributes regardless of whether they attribute format, forward the attributes regardless of whether they
understand the TLV's encoded in the attribute not. For this the understand the TLV's encoded in the attribute not. For this the
first bit in the Type field is reserved. If this bit is set then the first bit in the Type field is reserved. If this bit is set then the
skipping to change at page 4, line 19 skipping to change at page 4, line 19
Having the attribute hello option does not guarantee that all Having the attribute hello option does not guarantee that all
neighbors understand all possible individual attributes. As there's neighbors understand all possible individual attributes. As there's
no immediate way to act on a neighbor's incapability to process no immediate way to act on a neighbor's incapability to process
certain attribute types, it is not desired to have a hello option for certain attribute types, it is not desired to have a hello option for
each possible attribute type. each possible attribute type.
3.4. Conflicting attributes 3.4. Conflicting attributes
It's possible that a router receives conflicting attribute It's possible that a router receives conflicting attribute
information from different downstream routers. See Figure 2. information from different downstream routers. Conflicts only occur
with attributes of the same type. If two different attributes of two
different types are received they should both be processed and
forwarded.
( Edge A1 ) ( Edge B1 )---- [R1] ( Edge A1 ) ( Edge B1 )---- [R1]
/ \ / / \ /
/ \ / / \ /
[S] ( Core ) [S] ( Core )
\ / \ \ / \
\ / \ \ / \
( Edge A2 ) ( Edge B2 )---- [R2] ( Edge A2 ) ( Edge B2 )---- [R2]
Figure 2 Figure 2
An example join attribute in this case is an exit router. There are An example join attribute in this case is an exit router. There are
2 receivers for the same group connected to Edge B1 and B2. Suppose 2 receivers for the same group connected to Edge B1 and B2. Suppose
that edge router B1 prefers A1 as the exit point and B2 prefers A2 as that edge router B1 prefers A1 as the exit point and B2 prefers A2 as
exit point to reach the source S. If both Edge B1 and B2 send a Join exit point to reach the source S. If both Edge B1 and B2 send a Join
including an attribute to prefer their exit router in the network and including an attribute to prefer their exit router in the network and
they cross the same core router, the core router will get conflicting they cross the same core router, the core router will get conflicting
attribute information for the source. If this happens we use the attribute information for the source. If this happens we use the
Attribute from the PIM adjacency with the numerically smallest IP Attribute from the PIM adjacency with the numerically smallest IP
address. The attributes from other sending routers may be kept address. In the case of IPv6, the link local address will be used.
around in case the best attribute gets pruned or expires, we are able When two neighbors have the same IP address, either for IPv4 or IPv6,
to immediately use the second best attribute and converge quickly the interface index must be used as a tie breaker. The attributes
without waiting for the next periodic update. If a TLV has its own from other sending routers may be kept around in case the best
definition for conflict resolution it is preferred over the conflict attribute gets pruned or expires, we are able to immediately use the
resolution above. second best attribute and converge quickly without waiting for the
next periodic update. If a TLV has its own definition for conflict
resolution it is preferred over the conflict resolution above.
3.5. Attribute Convergence 3.5. Attribute Convergence
An attribute is included in a PIM Join message together with the An attribute is included in a PIM Join message together with the
source information. If the attribute for this source is changed, we source information. If the attribute for this source is changed, we
trigger a new PIM Join message to the upstream router. This causes trigger a new PIM Join message to the upstream router. This causes
the new attribute to be propagated. This new attribute implicitly the new attribute to be propagated. This new attribute implicitly
removes the old attribute upstream. If processing the new attribute removes the old attribute upstream. If processing the new attribute
results in a change in the distribution tree, a PIM Prune message may results in a change in the distribution tree, a PIM Prune message may
be sent. This PIM Prune does not need to carry any attribute, the be sent. This PIM Prune does not need to carry any attribute, the
sender of the prune and the source and group information is enough to sender of the prune and the source and group information is enough to
identify the entry. The attribute information is removed immediately identify the entry. The attribute information is removed immediately
and possibly a new attribute is chosen from the database if and possibly a new attribute is chosen from the database if
available. available.
3.6. Multiple attributes 3.6. Multiple attributes
A PIM Join can contain multiple attributes. The attributes are A PIM Join can contain multiple attributes. The attributes are
encoded as TLVs associated with a new PIM source type in the PIM encoded as TLVs associated with a new PIM source type in the PIM
message. When a PIM Join with multiple attributes is received, the message. When a PIM Join with multiple attributes is received, each
first attribute is processed, and the action taken depends upon the type is processed separately. For each type, the first attribute of
attribute type. This may or may not result in the processing of the that type is processed, and the action taken depends upon the type.
next attribute. Attributes that the router understands but are not This may or may not result in the processing of the next attribute.
processed MUST be passed upstream unchanged. Attributes that the router understands but are not processed MUST be
passed upstream unchanged.
3.7. Applicability of the attributes 3.7. Applicability of the attributes
PIM Joins with attributes can be applied to both shared-trees rooted PIM Joins with attributes can be applied to both shared-trees rooted
at a Rendezvous Point (RP) and shortest-path trees as described in at a Rendezvous Point (RP) and shortest-path trees as described in
[I-D.ietf-pim-sm-v2-new]. [RFC4601].
3.8. PIM attribute packet format 3.8. PIM attribute packet format
3.8.1. PIM Join packet format 3.8.1. PIM Join packet format
There is no space in the default PIM source encoding to include a There is no space in the default PIM source encoding to include a
attribute field. Therefore we introduce a new source encoding type. attribute field. Therefore we introduce a new source encoding type.
The attributes are formatted as TLV's. The new Encoded source The attributes are formatted as TLV's. The new Encoded source
address looks like this: address looks like this:
skipping to change at page 6, line 13 skipping to change at page 6, line 29
F bit, Forward Unknown TLV. If this bit is set the TLV is forwarded F bit, Forward Unknown TLV. If this bit is set the TLV is forwarded
regardless if the router understands the Type. regardless if the router understands the Type.
S bit, Bottom of Stack. If this bit is set then this is the last TLV S bit, Bottom of Stack. If this bit is set then this is the last TLV
in the stack. in the stack.
Type field of the TLV is 6 bits. Type field of the TLV is 6 bits.
Length field of the TLV is 1 byte. Length field of the TLV is 1 byte.
The other fields are the same as described in the PIM spec. The other fields are the same as described in the RFC 4601.
[I-D.ietf-pim-sm-v2-new]. [RFC4601].
The source TLV encoding type: TBD. The source TLV encoding type: TBD.
3.8.2. PIM Attribute Hello option 3.8.2. PIM Attribute Hello option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OptionType = TBD | OptionLength = 0 | | OptionType = TBD | OptionLength = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 6, line 36 skipping to change at page 7, line 5
4. IANA Considerations 4. IANA Considerations
This document requires a new PIM Hello Option value and a new PIM This document requires a new PIM Hello Option value and a new PIM
Join Encoding type. Join Encoding type.
5. Security Considerations 5. Security Considerations
Security of the join attribute is only guaranteed by the security of Security of the join attribute is only guaranteed by the security of
the PIM packet, so the security considerations for PIM join packets the PIM packet, so the security considerations for PIM join packets
as described in PIM-SM [I-D.ietf-pim-sm-v2-new] apply here. as described in PIM-SM [RFC4601] apply here.
6. Acknowledgments 6. Acknowledgments
The authors would like to thank James Lingard, Bharat Joshi, Marshall The authors would like to thank Stig Venaas, James Lingard, Bharat
Eubanks, Stig Venaas, Pekka Savola and Tom Pusateri for their input. Joshi, Marshall Eubanks, Pekka Savola and Tom Pusateri for their
input.
7. References 7. References
7.1. Normative References 7.1. Normative References
[I-D.ietf-pim-sm-v2-new] [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
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)",
draft-ietf-pim-sm-v2-new-11 (work in progress),
October 2004.
7.2. Informative References 7.2. Informative References
Authors' Addresses Authors' Addresses
Arjen Boers Arjen Boers
Cisco Systems, Inc. Cisco Systems, Inc.
Avda. Diagonal, 682 Avda. Diagonal, 682
Barcelona 08034 Barcelona 08034
Spain Spain
skipping to change at page 8, line 22 skipping to change at page 8, line 4
Email: aboers@cisco.com Email: aboers@cisco.com
IJsbrand Wijnands IJsbrand Wijnands
Cisco Systems, Inc. Cisco Systems, Inc.
De kleetlaan 6a De kleetlaan 6a
Diegem 1831 Diegem 1831
Belgium Belgium
Email: ice@cisco.com Email: ice@cisco.com
Eric Rosen Eric Rosen
Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts Avenue 1414 Massachusetts Avenue
Boxborough, Ma 01719 Boxborough, Ma 01719
Email: erosen@cisco.com Email: erosen@cisco.com
Intellectual Property Statement Full Copyright Statement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
skipping to change at page 9, line 29 skipping to change at page 9, line 45
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is provided by the IETF
Internet Society. Administrative Support Activity (IASA).
 End of changes. 19 change blocks. 
53 lines changed or deleted 56 lines changed or added

This html diff was produced by rfcdiff 1.33. The latest version is available from http://tools.ietf.org/tools/rfcdiff/