Network Working Group J. Xie
Internet-Draft Huawei Technologies
Intended status: Standards Track A. Wang
Expires: July 17, 2020 China Telecom
G. Yan
S. Dhanaraj
Huawei Technologies
January 14, 2020
BIER IPv6 Encapsulation (BIERv6) Support via IS-IS
draft-xie-bier-ipv6-isis-extension-01
Abstract
This document defines IS-IS extensions to support multicast
forwarding using the Bit Index Explicit Replication (BIER) with IPv6
encapsulation (BIERv6).
Requirements Language
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] and
[RFC8174].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 17, 2020.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Specification . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Encapsulation sub-sub-TLV of End.BIER address . . . . . . 3
3.2. Encapsulation sub-sub-TLV of BIFT-id for each BSL . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5.1. Encapsulation sub-sub-TLV Type Code . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
This document defines IS-IS extensions to support multicast
forwarding using the Bit Index Explicit Replication (BIER) with IPv6
encapsulation (BIERv6).
The BIER IPv6 encapsulation [I-D.xie-bier-ipv6-encapsulation] uses a
"BIER specific" IPv6 unicast address, the "End.BIER" address,
configured locally on a BIER Forwarding Router (BFR) to indicate a
"BIER specific handling" in Forwarding Information Base (FIB). This
BIER specific IPv6 address, used as part of BIER IPv6 encapsulation,
is advertised as a type of Encapsulation sub-sub-TLV within the BIER
Info sub-TLV defined [RFC8401].
The BIFT-id field for each BSL of each Sub-domain is another part of
BIER IPv6 encapsulation, and is advertised as a type of Encapsulation
sub-sub-TLV within the BIER Info sub-TLV defined [RFC8401].
The BIER Sub-TLV is advertised within the extended IP reachability
TLV as specified by in [RFC8401].
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Note the extended IP reachability only includes the TLV 236 (IPv6 IP
Reach TLV) [RFC5308] and TLV 237 (MT IPv6 IP Reach TLVs) [RFC5120] in
this document.
The following restrictions defined for BIER Sub-TLV in section 4.2 of
[RFC8401] apply equally to this document:
o Prefix length MUST be 128 for an IPv6 prefix.
o When the Prefix Attributes Flags sub-TLV [RFC7794] is present, the
N flag MUST be set and the R flag MUST NOT be set.
o BIER sub-TLVs and Function Sub-TLVs MUST be included when a prefix
reachability advertisement is leaked between levels.
2. Terminology
Readers of this document are assumed to be familiar with the
terminology and concepts of the documents listed as Normative
References.
3. Specification
3.1. Encapsulation sub-sub-TLV of End.BIER address
The Encapsulation sub-sub-TLV carries the information for the
End.BIER address of a sub-domain for BIER IPv6 encapsulation. It is
advertised within the BIER Info sub-TLV defined in [RFC8401] which
in-turn is carried within the TLVs 236 or 237. This sub-sub-TLV MUST
appear no more than one time within a single BIER Info sub-TLV. If
the sub-sub-TLV appears more than one time, the BIER Info sub-TLV
MUST be ignored.
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| End.BIER address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 1 octet value indicating "Encapsulation of End.BIER" this IPv6
prefix bound to. TBD1 to be assigned by IANA.
Length: 1 octet length in octets. Value 16 is set to this field.
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End.BIER address: 16 octets IPv6 address.
3.2. Encapsulation sub-sub-TLV of BIFT-id for each BSL
The Encapsulation sub-sub-TLV carries the information for the BIER
IPv6 encapsulation of a specific BitString length. It is advertised
within the BIER Info sub-TLV defined in [RFC8401] which in-turn is
carried within the TLVs 236 or 237. This sub-sub-TLV MAY appear
multiple times within a single BIER Info sub-TLV. If the same
BitString length is repeated in multiple sub-sub-TLVs inside the same
BIER Info sub- TLV, the BIER Info sub-TLV MUST be ignored.
When a BIER IPv6 encapsulation sub-sub-TLV of BIFT-id for any BSL
appears in a BIER Info sub-TLV, one End.BIER Encapsulation sub-sub-
TLV MUST appears in the BIER info sub-TLV, otherwise the BIER Info
sub-TLV MUST be ignored.
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max SI |BS Len | BIFT-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 1 octet value indicating BIER IPv6 encapsulation. TBD2 to be
assigned by IANA.
Length: 1 octet length in octets. Value 4 is set to this field.
Max SI: 1 octet value. Maximum Set Identifier (Section 1 of
[RFC8279]) used in the encapsulation for this BIER subdomain for this
BitString length. Each SI maps to a single BIFT-id in the BIFT-id
range. The first BIFT-id is for SI=0, the second BIFT-id is for
SI=1, etc. If the BIFT-id associated with the Maximum Set Identifier
exceeds the 20-bit range, the sub-sub-TLV MUST be ignored.
BS Len: 4 bits value of Local BitString Length. Encoded BitString
length as per [RFC8296].
BIFT-id: 20 bits value. First BIFT-id of the range. The BIFT-id(s)
are as defined in [RFC8296], or refer to
[I-D.ietf-bier-lsr-ethernet-extensions] for Non-MPLS encapsulation.
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4. Security Considerations
The procedures of this document do not, in themselves, provide
privacy, integrity, or authentication for the control plane or the
data plane.
5. IANA Considerations
5.1. Encapsulation sub-sub-TLV Type Code
Allocation is expected from IANA for two sub-sub-TLV codepoints from
the "sub-sub-TLVs for BIER Info sub-TLV" sub-registry.
Type: TBD1 to be assigned by IANA.
Name: BIER IPv6 encapsulation of End.BIER address.
Reference: This document.
Type: TBD2 to be assigned by IANA.
Name: BIER IPv6 Encapsulation of BIFT-id for each BSL.
Reference: This document
6. Acknowledgements
TBD.
7. References
7.1. Normative References
[I-D.ietf-bier-lsr-ethernet-extensions]
Dhanaraj, S., Wijnands, I., Psenak, P., Zhang, Z., Yan,
G., and J. Xie, "LSR Extensions for BIER over Ethernet",
draft-ietf-bier-lsr-ethernet-extensions-01 (work in
progress), July 2019.
[I-D.xie-bier-ipv6-encapsulation]
Xie, J., Geng, L., McBride, M., Asati, R., and S.
Dhanaraj, "Encapsulation for BIER in Non-MPLS IPv6
Networks", draft-xie-bier-ipv6-encapsulation-04 (work in
progress), December 2019.
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[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008,
<https://www.rfc-editor.org/info/rfc5120>.
[RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308,
DOI 10.17487/RFC5308, October 2008,
<https://www.rfc-editor.org/info/rfc5308>.
[RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and
U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4
and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794,
March 2016, <https://www.rfc-editor.org/info/rfc7794>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>.
7.2. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Authors' Addresses
Jingrong Xie
Huawei Technologies
Email: xiejingrong@huawei.com
Aijun Wang
China Telecom
Email: wangaj3@chinatelecom.cn
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Gang Yan
Huawei Technologies
Email: yangang@huawei.com
Senthil Dhanaraj
Huawei Technologies
Email: senthil.dhanaraj@huawei.com
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