draft-ietf-bier-isis-extensions-08.txt   draft-ietf-bier-isis-extensions-09.txt 
Internet Engineering Task Force L. Ginsberg, Ed. Internet Engineering Task Force L. Ginsberg, Ed.
Internet-Draft Cisco Systems Internet-Draft Cisco Systems
Intended status: Standards Track A. Przygienda Intended status: Standards Track A. Przygienda
Expires: August 26, 2018 Juniper Networks Expires: August 27, 2018 Juniper Networks
S. Aldrin S. Aldrin
Google Google
J. Zhang J. Zhang
Juniper Networks, Inc. Juniper Networks, Inc.
February 22, 2018 February 23, 2018
BIER support via ISIS BIER support via ISIS
draft-ietf-bier-isis-extensions-08 draft-ietf-bier-isis-extensions-09
Abstract Abstract
This document defines ISIS extensions to support multicast forwarding This document defines ISIS extensions to support multicast forwarding
using the Bit Index Explicit Replication (BIER) architecture. using the Bit Index Explicit Replication (BIER) architecture.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
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 August 26, 2018. This Internet-Draft will expire on August 27, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 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
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
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. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4. Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. BIER Domains and Sub-Domains . . . . . . . . . . . . . . 5 4.1. BIER Domains and Sub-Domains . . . . . . . . . . . . . . 5
4.2. Advertising BIER Information . . . . . . . . . . . . . . 5 4.2. Advertising BIER Information . . . . . . . . . . . . . . 5
5. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 5 5. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1. Multi Topology and Sub-Domain . . . . . . . . . . . . . . 5 5.1. Multi Topology and Sub-Domain . . . . . . . . . . . . . . 5
5.2. Label advertisements for MPLS Encapsulation . . . . . . . 6 5.2. BFR-id Advertisements . . . . . . . . . . . . . . . . . . 6
5.3. BFR-id Advertisements . . . . . . . . . . . . . . . . . . 6 5.3. Logging Misconfiguration . . . . . . . . . . . . . . . . 6
5.4. Logging Misconfiguration . . . . . . . . . . . . . . . . 6 5.4. Flooding Reduction . . . . . . . . . . . . . . . . . . . 6
5.5. Flooding Reduction . . . . . . . . . . . . . . . . . . . 6 6. Packet Formats . . . . . . . . . . . . . . . . . . . . . . . 6
6. Packet Formats . . . . . . . . . . . . . . . . . . . . . . . 7
6.1. BIER Info sub-TLV . . . . . . . . . . . . . . . . . . . . 7 6.1. BIER Info sub-TLV . . . . . . . . . . . . . . . . . . . . 7
6.2. BIER MPLS Encapsulation sub-sub-TLV . . . . . . . . . . . 8 6.2. BIER MPLS Encapsulation sub-sub-TLV . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . 9
9.2. Informative References . . . . . . . . . . . . . . . . . 10 9.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
Bit Index Explicit Replication (BIER) [RFC8279] defines an Bit Index Explicit Replication (BIER) [RFC8279] defines an
architecture where all intended multicast receivers are encoded as architecture where all intended multicast receivers are encoded as
bitmask in the Multicast packet header within different bitmask in the Multicast packet header within different
encapsulations such as [RFC8296]. A router that receives such a encapsulations such as [RFC8296]. A router that receives such a
packet will forward the packet based on the Bit Position in the packet will forward the packet based on the Bit Position in the
packet header towards the receiver(s), following a precomputed tree packet header towards the receiver(s), following a precomputed tree
for each of the bits in the packet. Each receiver is represented by for each of the bits in the packet. Each receiver is represented by
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used and the type of tree it is using to forward BIER frames used and the type of tree it is using to forward BIER frames
(currently always SPF). Additionally, per supported bitstring length (currently always SPF). Additionally, per supported bitstring length
in the sub-domain, each router will advertise the necessary label in the sub-domain, each router will advertise the necessary label
ranges to support it. ranges to support it.
4.2. Advertising BIER Information 4.2. Advertising BIER Information
BIER information advertisements are associated with a new sub-TLV in BIER information advertisements are associated with a new sub-TLV in
the extended reachability TLVs. BIER information is always the extended reachability TLVs. BIER information is always
associated with a host prefix which MUST be a node address for the associated with a host prefix which MUST be a node address for the
advertising node. The following restrictions apply: advertising node. If this is not the case the advertisement MUST be
ignored. Therefore the following restrictions apply:
o Prefix length MUST be 32 for an IPv4 prefix or 128 for an IPv6 o Prefix length MUST be 32 for an IPv4 prefix or 128 for an IPv6
prefix prefix
o When the Prefix Attributes Flags sub-TLV is present N flag MUST be o When the Prefix Attributes Flags sub-TLV is present N flag MUST be
set. [RFC7794] set and R flag MUST NOT be set. [RFC7794]
o BIER sub-TLVs MUST be included when a prefix reachability o BIER sub-TLVs MUST be included when a prefix reachability
advertisement is leaked between levels. advertisement is leaked between levels.
5. Procedures 5. Procedures
5.1. Multi Topology and Sub-Domain 5.1. Multi Topology and Sub-Domain
A given sub-domain is supported within one and only one topology. A given sub-domain is supported within one and only one topology.
All routers in the flooding scope of the BIER sub-TLVs MUST advertise All routers in the flooding scope of the BIER sub-TLVs MUST advertise
the same sub-domain within the same multi-topology. A router the same sub-domain within the same multi-topology. A router
receiving an <MT,SD> advertisement which does not match the locally receiving an <MT,SD> advertisement which does not match the locally
configured pair MUST report a misconfiguration of the received configured pair MUST report a misconfiguration of the received
<MT,SD> pair. All received BIER advertisements associated with the <MT,SD> pair. All received BIER advertisements associated with the
conflicting <MT,SD> pair MUST be ignored. conflicting <MT,SD> pair MUST be ignored. Note that in the presence
of such a misconfiguration this will lead to partitioning of the sub-
domian.
Example: Example:
The following combination of advertisements are valid: <0,0> <0,1> The following combination of advertisements are valid: <0,0> <0,1>
<2,2>. <2,2>.
The following combination of advertisements are invalid: <0,0> <0,1> The following combination of advertisements are invalid: <0,0> <0,1>
<2,0>. Advertisements associated with <0,0> and <2,0> MUST be <2,0>. Advertisements associated with <0,0> and <2,0> must be
ignored. ignored.
5.2. Label advertisements for MPLS Encapsulation 5.2. BFR-id Advertisements
A router that desires to participate in <MT,SD> MUST advertise for
each bitstring length it supports in <MT,SD> a Maximum Set ID that
guarantees to cover the maximum BFR-id injected into <MT,SD> (which
implies a certain maximum set id per bitstring length as described in
[RFC8279]). Any router that violates this condition MUST be excluded
from BIER BFTs for <MT,SD>.
5.3. BFR-id Advertisements
Each BFER/BFIR MAY advertise with its TLV<MT,SD> the BFR-id that it If a BFER/BFIR is configured with a BFR-id then it advertises this
has administratively chosen. A valid BFR-id MUST be unique within value in its BIER advertisements. If no BFR-id is configured then
the flooding scope of the BIER advertisements. All BFERs/BFIRs MUST the value "Invalid BFR-id" is advertised. A valid BFR-id MUST be
detect advertisement of duplicate valid BFR-IDs for a given <MT, SD>. unique within the flooding scope of the BIER advertisements. All
When such duplication is detected all of the routers advertising BFERs/BFIRs MUST detect advertisement of duplicate valid BFR-IDs for
duplicates MUST be treated as if they did not advertise a valid BFR- a given <MT, SD>. When such duplication is detected all of the
id. This implies they cannot act as BFER or BFIR in that <MT,SD>. routers advertising duplicates MUST be treated as if they did not
advertise a valid BFR-id. This implies they cannot act as BFER or
BFIR in that <MT,SD>.
5.4. Logging Misconfiguration 5.3. Logging Misconfiguration
Whenever an advertisement is received which violates any of the Whenever an advertisement is received which violates any of the
constraints defined in this document the receiving router MUST constraints defined in this document the receiving router MUST
support logging this occurrence. Logging SHOULD be dampened to avoid support logging this occurrence. Logging SHOULD be dampened to avoid
excessive output. excessive output.
5.5. Flooding Reduction 5.4. Flooding Reduction
BIER domain information SHOULD change infrequently. Frequent changes It is expected that changes in BIER domain information which is
will increase the number of Link State PDU (LSP) updates and advertised by IS-IS occur infrequently. If this expectation is not
negatively impact performance in the network. met for an extended period of time (more than a few seconds of
burstiness) changes will increase the number of Link State PDU (LSP)
updates and negatively impact performance in the network.
Implementations SHOULD protect against this possibility e.g., by
dampening updates if they occur over an extended period of time.
6. Packet Formats 6. Packet Formats
All ISIS BIER information is carried within the TLVs 235, 237 All ISIS BIER information is carried within the TLVs 235, 237
[RFC5120] or TLVs 135 [RFC5305], or TLV 236 [RFC5308]. [RFC5120] or TLVs 135 [RFC5305], or TLV 236 [RFC5308].
6.1. BIER Info sub-TLV 6.1. BIER Info sub-TLV
This sub-TLV carries the information for the BIER sub-domains that This sub-TLV carries the information for the BIER sub-domains that
the router participates in as BFR. This sub-TLV MAY appear multiple the router participates in as BFR. This sub-TLV MAY appear multiple
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from the BIER Algorithm Registry. 1 octet from the BIER Algorithm Registry. 1 octet
IPA IGP algorithm. Specifies an IGP Algorithm to either modify, IPA IGP algorithm. Specifies an IGP Algorithm to either modify,
enhance or replace the calculation of underlay paths to reach enhance or replace the calculation of underlay paths to reach
BFERs as defined by the BAR value. Values are from the IGP BFERs as defined by the BAR value. Values are from the IGP
Algorithm registry. 1 octet Algorithm registry. 1 octet
subdomain-id: Unique value identifying the BIER sub-domain. 1 octet subdomain-id: Unique value identifying the BIER sub-domain. 1 octet
BFR-id: A 2 octet field encoding the BFR-id, as documented in BFR-id: A 2 octet field encoding the BFR-id, as documented in
[RFC8279]. If no BFR-id has been assigned this field is set to [RFC8279]. If no BFR-id has been assigned the value of this field
the invalid BFR-id. is set to "Invalid BFR-id", which is defined as illegal in
[RFC8279] .
The use of non-zero values in either the BAR field or the IPA field The use of non-zero values in either the BAR field or the IPA field
is outside the scope of this document. If an implementation does not is outside the scope of this document. If an implementation does not
support the use of non-zero values in these fields, but receives a support the use of non-zero values in these fields, but receives a
BIER Info sub-TLV containing non-zero values in these fields, it BIER Info sub-TLV containing non-zero values in these fields, it
SHOULD treat the advertising router as incapable of supporting BIER SHOULD treat the advertising router as incapable of supporting BIER
(one way of handling incapable routers is documented in section 6.9 (one way of handling incapable routers is documented in section 6.9
of [RFC8279] and additional methods may be defined in the future). of [RFC8279] and additional methods may be defined in the future).
6.2. BIER MPLS Encapsulation sub-sub-TLV 6.2. BIER MPLS Encapsulation sub-sub-TLV
This sub-sub-TLV carries the information for the BIER MPLS This sub-sub-TLV carries the information for the BIER MPLS
encapsulation including the label range for a specific bitstring encapsulation including the label range for a specific bitstring
length for a certain <MT,SD>. It is advertised within the BIER Info length for a certain <MT,SD>. It is advertised within the BIER Info
sub-TLV (Section 6.1) . This sub-sub-TLV MAY appear multiple times sub-TLV (Section 6.1) . This sub-sub-TLV MAY appear multiple times
within a single BIER info sub-TLV. within a single BIER info sub-TLV.
On violation of any of the following conditions, the receiving router If the same Bitstring length is repeated in multiple sub-sub-TLVs
MUST ignore the encapsulating BIER Info sub-TLV. inside the same BIER Info Sub-TLV, the BIER Info sub-TLV MUST be
ignored.
o Label ranges in multiple sub-sub-TLVs MUST NOT overlap.
o Bitstring lengths in multiple sub-sub-TLVs MUST NOT be identical.
o The sub-sub-TLV MUST include the required bitstring lengths Label ranges within all BIER MPLS Encapsulation sub-sub-TLVs across
encoded in precisely the same way as in [RFC8296]. all BIER Info sub-TLVs advertised by the same BFR MUST NOT overlap.
If overlap is detected, the advertising router MUST be treated as if
it did not advertise any BIER sub-TLVs.
o All labels in the range MUST represent valid label values Label values MUST NOT match any of the reserved values defined in
[RFC3032]
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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max SI |BS Len | Label | | Max SI |BS Len | Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: value of 1 indicating MPLS encapsulation. Type: value of 1 indicating MPLS encapsulation.
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Security concerns for IS-IS are addressed in [RFC5304] and [RFC5310]. Security concerns for IS-IS are addressed in [RFC5304] and [RFC5310].
Advertisement of the additional information defined in this document Advertisement of the additional information defined in this document
introduces no new security concerns. introduces no new security concerns.
BIER specific security considerations are discussed in [RFC8279]. BIER specific security considerations are discussed in [RFC8279].
8. Acknowledgements 8. Acknowledgements
The RFC is aligned with the The RFC is aligned with the
[I-D.draft-ietf-bier-ospf-bier-extensions-14] draft as far as the [I-D.draft-ietf-bier-ospf-bier-extensions-15] draft as far as the
protocol mechanisms overlap. protocol mechanisms overlap.
Many thanks for comments from (in no particular order) Hannes Many thanks for comments from (in no particular order) Hannes
Gredler, Ijsbrand Wijnands, Peter Psenak and Chris Bowers. Gredler, Ijsbrand Wijnands, Peter Psenak and Chris Bowers.
9. References 9. References
9.1. Normative References 9.1. Normative References
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, DOI 10.17487/RFC1195, dual environments", RFC 1195, DOI 10.17487/RFC1195,
December 1990, <https://www.rfc-editor.org/info/rfc1195>. December 1990, <https://www.rfc-editor.org/info/rfc1195>.
[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, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
<https://www.rfc-editor.org/info/rfc3032>.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120, Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008, DOI 10.17487/RFC5120, February 2008,
<https://www.rfc-editor.org/info/rfc5120>. <https://www.rfc-editor.org/info/rfc5120>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <https://www.rfc-editor.org/info/rfc5304>. 2008, <https://www.rfc-editor.org/info/rfc5304>.
skipping to change at page 10, line 29 skipping to change at page 10, line 25
U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4 U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4
and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794, and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794,
March 2016, <https://www.rfc-editor.org/info/rfc7794>. March 2016, <https://www.rfc-editor.org/info/rfc7794>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
9.2. Informative References 9.2. Informative References
[I-D.draft-ietf-bier-ospf-bier-extensions-14] [I-D.draft-ietf-bier-ospf-bier-extensions-15]
Psenak et al., P., "OSPF Extension for Bit Index Explicit Psenak et al., P., "OSPF Extension for Bit Index Explicit
Replication", internet-draft draft-ietf-bier-ospf-bier- Replication", internet-draft draft-ietf-bier-ospf-bier-
extensions-14, February 2018. extensions-15, February 2018.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279, Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017, DOI 10.17487/RFC8279, November 2017,
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