Network Working Group H. Chen
Internet-Draft M. McBride
Intended status: Standards Track Futurewei
Expires: January 7, 2023 R. Chen
ZTE Corporation
G. Mishra
Verizon Inc.
A. Wang
China Telecom
Y. Liu
China Mobile
Y. Fan
Casa Systems
B. Khasanov
Yandex LLC
L. Liu
Fujitsu
X. Liu
IBM Corporation
July 6, 2022
BGP for BIER-TE Path
draft-chen-idr-bier-te-path-05
Abstract
This document describes extensions to Border Gateway Protocol (BGP)
for distributing a Bit Index Explicit Replication Traffic/Tree
Engineering (BIER-TE) path. A new Tunnel Type for BIER-TE path is
defined to encode the information about a BIER-TE path.
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] [RFC8174]
when, and only when, they appear in all capitals, as shown here.
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
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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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 January 7, 2023.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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publication of this document. Please review these documents
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminologies . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview of BGP for BIER-TE Path . . . . . . . . . . . . . . 4
2.1. Example BIER-TE Topology with BGP . . . . . . . . . . . . 4
2.2. Distributing Path to Ingress . . . . . . . . . . . . . . 5
3. Extensions to BGP . . . . . . . . . . . . . . . . . . . . . . 6
3.1. New SAFI and NLRI . . . . . . . . . . . . . . . . . . . . 6
3.2. New Tunnel Type for BIER-TE . . . . . . . . . . . . . . . 7
3.3. Path BitStrings Sub-TLV . . . . . . . . . . . . . . . . . 7
3.4. Path Name Sub-TLV . . . . . . . . . . . . . . . . . . . . 8
3.5. Traffic Description Sub-TLVs . . . . . . . . . . . . . . 9
4. Security Considerations . . . . . . . . . . . . . . . . . . . 11
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6.1. Existing Registry: SAFI Parameters . . . . . . . . . . . 11
6.2. Existing Registry: BGP TEA Tunnel Types . . . . . . . . . 11
6.3. Existing Registry: BGP TEA sub-TLVs . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Normative References . . . . . . . . . . . . . . . . . . 12
7.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Extensions to PMSI_TUNNEL Attribute . . . . . . . . 13
A.1. New Tunnel Type for BIER-TE . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
[I-D.ietf-bier-te-arch] introduces Bit Index Explicit Replication
(BIER) Tree Engineering (BIER-TE). It is an architecture for per-
packet stateless explicit point to multipoint (P2MP) multicast path/
tree, which is called BIER-TE path, and based on the BIER
architecture defined in [RFC8279].
A Bit-Forwarding Router (BFR) in a BIER-TE domain has a BIER-TE Bit
Index Forwarding Table (BIFT). A BIER-TE BIFT on a BFR comprises a
forwarding entry for a BitPosition (BP) assigned to each of the
adjacencies of the BFR. If the BP represents a forward connected
adjacency, the forwarding entry for the BP forwards the multicast
packet with the BP to the directly connected BFR neighbor of the
adjacency. If the BP represents a BFER (i.e., egress node) or say a
local decap adjacency, the forwarding entry for the BP decapsulates
the multicast packet with the BP and passes a copy of the payload of
the packet to the packet's NextProto within the BFR.
A Bit-Forwarding Ingress Router (BFIR) in a BIER-TE domain receives
the information or instructions about which multicast flows/packets
are mapped to which BIER-TE paths that are represented by
BitPositions or say BitStrings. After receiving the information or
instructions, the ingress node/router encapsulates the multicast
packets with the BitStrings for the corresponding BIER-TE paths,
replicates and forwards the packets with the BitStrings along the
BIER-TE paths. When the BitStrings is for a regular BIER path, the
multicast packet is forwarded along the BIER path.
This document proposes some procedures and extensions to BGP for
distributing a BIER-TE path to the Bit-Forwarding Ingress Router
(BFIR) of the path. It specifies a way of encoding the information
about a BIER-TE path in a BGP UPDATE message, which can be
distributed to the BFIR of the path.
1.1. Terminologies
The following terminologies are used in this document.
BIER: Bit Index Explicit Replication.
BIER-TE: BIER Tree Engineering.
BFR: Bit-Forwarding Router.
BFIR: Bit-Forwarding Ingress Router.
BFER: Bit-Forwarding Egress Router.
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BFR-id: BFR Identifier. It is a number in the range [1,65535].
BFR-NBR: BFR Neighbor.
BFR-prefix: An IP address (either IPv4 or IPv6) of a BFR.
BIRT: Bit Index Routing Table. It is a table that maps from the BFR-
id (in a particular sub-domain) of a BFER to the BFR-prefix of
that BFER, and to the BFR-NBR on the path to that BFER.
BIFT: Bit Index Forwarding Table.
P-tunnel: A multicast tunnel through the network of one or more SPs.
PMSI: Provider Multicast Service Interface. PMSI is an abstraction
that represents a multicast service for carrying packets. A
PMSI is instantiated via one or more P-tunnels.
I-PMSI A-D Route: Inclusive PMSI Auto-Discovery route.
S-PMSI A-D route: Selective PMSI Auto-Discovery route.
x-PMSI A-D route: A route that is either an I-PMSI A-D route or an
S-PMSI A-D route.
2. Overview of BGP for BIER-TE Path
This section briefs the BGP for BIER-TE path and illustrates some
details through a simple example BIER-TE topology.
2.1. Example BIER-TE Topology with BGP
An example BIER-TE domain topology using SDN controller with a BGP to
distribute BIER-TE path is shown in Figure 1. There are 8 nodes/BFRs
A, B, C, D, E, F, G and H in the domain. Nodes/BFRs A, H, E, F and D
are BFIRs (i.e., ingress nodes) or BFERs (i.e., egress nodes). The
controller has a BGP session with each of the edge nodes in the
domain, including BFIRs (i.e., ingress nodes A, H, E, F and D), and
each of the non edge nodes in the domain (i.e., nodes B, C and G).
Note that some of connections and the BGP on each edge node are not
shown in the figure.
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+------------------------------------+
| SND controller with BGP |
+------------------------------------+
/ ... \ \
/ \ \
/ 4' \ 17' 18' \
/ /-----------( G )----------( H )
/ / 19'\_______ 12'/4
/ / _______)____/
/ / / (_____
/ /3' / \
/ 1' 2' / 5' 6' /11' 13' 20'\
(CE) --- ( A )--------( B )------------( C )------------( D )
5 \7' \15' 14' 1
\ \
\8' 9' 10' \16'
( E )------------( F )
3 2
Figure 1: Example BIER-TE Topology with Controller
Nodes/BFRs D, F, E, H and A are BFERs (or BFIRs) and have local decap
adjacency BitPositions 1, 2, 3, 4, and 5 respectively.
The BitPositions for the forward connected adjacencies are
represented by i', where i is from 1 to 20.
2.2. Distributing Path to Ingress
This section describes how the SDN controller distributes a BIER-TE
path to its ingress node.
Suppose that node A in Figure 1 wants to have a BIER-TE path from
ingress node A to egress nodes H and F. The path satisfies a set of
constraints. The controller obtains the request from an application
or user configuration. It finds a BIER-TE path satisfying the
constraints and distributes the path to ingress node A.
The controller advertises a BGP Update message to all its BGP peers,
where the message contains the information about the path, a route
target (RT) matching the BGP identifier (ID) of ingress node A. Each
of the BGP peers advertises the received Update to its BGP neighbors
according to normal BGP propagation rules. Eventually, ingress node
A accepts this message after determining the RT in the message
matches its BGP ID and installs a forwarding entry for the BIER-TE
path, which imports the packets to be transported by the path into
the path.
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3. Extensions to BGP
This section defines a new Tunnel Type (or say TLV) for BIER-TE path/
tunnel under Tunnel Encapsulation Attribute and a new SAFI. This new
SAFI and the existing AFI for IPv4/IPv6 pair uses a new NLRI for
indicating a BIER-TE Path.
3.1. New SAFI and NLRI
A new SAFI, called BIER-TE path SAFI, is defined. Its codepoint
(TBD1) is to be assigned by IANA. This new SAFI and the existing AFI
for IPv4/IPv6 pair uses a new NLRI, which is defined as follows:
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
+-+-+-+-+-+-+-+-+
| NLRI Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Distinguisher (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel Identifier (11/23 octets) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: NLRI Format
Where:
NLRI Length: 1 octet represents the length of NLRI. If the Length
is anything other than 15 or 27, the NLRI is corrupt and the
enclosing UPDATE message MUST be ignored.
Distinguisher: 4 octet value uniquely identifies the content/BIER-
TE path.
Tunnel Identifier: 11/23 octet value contains:
* sub-domain-id (1 octet): It is id of the sub domain through
which the BIER-TE tunnel crosses.
* BFR-id (2 octets): It is the BFR-id of the BFIR of the BIER-
TE tunnel.
* Tunnel-ID (4 octets): It is a number uniquely identifying a
BIER-TE tunnel within the BFIR and sub domain.
* BFR-prefix (4/16 octets): It is a BFR-prefix of the BFIR of
the BIER-TE tunnel. It occupies 4 octets for IPv4 and 16
octets for IPv6.
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3.2. New Tunnel Type for BIER-TE
A new Tunnel Type (or say TLV), called BIER-TE Path or Tunnel, is
defined under Tunnel Encapsulation Attribute in [RFC9012]. Its
codepoint is to be assigned by IANA. This new TLV with a number of
new sub-TLVs encodes the information about a BIER-TE path.
The structure encoding the information about a BIER-TE path is shown
below.
Attributes:
Tunnel Encaps Attribute (23)
Tunnel Type (TBD2): BIER-TE Path
Path BitStrings sub-TLV
Path Name sub-TLV
Traffic Description sub-TLV
Where:
o Tunnel Type (TBD2) is to be assigned by IANA.
o Path BitStrings sub-TLV encodes the bit positions of the BIER-TE
path.
o Path Name sub-TLV encodes the name of a BIER-TE path.
o Traffic Description sub-TLV encodes the multicast traffic that is
transported by the BIER-TE path.
3.3. Path BitStrings Sub-TLV
The bit positions of a BIER-TE path are encoded in a Path BitStrings
sub-TLV. The format of the sub-TLV is illustrated below.
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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 (TBD3) | Length (variable) | BitStringLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BIFT-id-1 | RSV | SI-1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitString-1 ~
| ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BIFT-id-n | RSV | SI-n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitString-n ~
| ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Path BitStrings Sub-TLV Format
Type: Its value (TBD3) is to be assigned by IANA.
Length: It is variable.
BitStringLen (Bit String Length) - 8 bits: The length in bits of the
BitString field according to [RFC8296]. If k is the length of the
BitString, the value of BitStringLen is log2(k)-5. For example,
BitStringLen = 1 indicates k = 64, BitStringLen = 7 indicates k =
4096.
<BIFT-id, SI, BitString> tuple: Each tuple <BIFT-id-i, SI-i,
BitString-i> (i = 1, 2, ..., n) represents/encodes a set of bit
positions on the BIER-TE path with a BIFT ID. All the tuples in
the sub-TLV represent/encode the BIER-TE path (i.e., all the bit
positions of the BIER-TE path).
3.4. Path Name Sub-TLV
The name of a BIER-TE path is encoded in a Path Name sub-TLV. The
format of the sub-TLV is illustrated below.
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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 (TBD4) | Length (variable) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Path Name String //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Path Name Sub-TLV Format
Type: Its value (TBD4) is to be assigned by IANA.
Length: It is variable.
Reserved: MUST be set to zero by the sender and MUST be ignored by
the receiver.
Path Name String: It represents/encodes the name of the BIER-TE path
in a string of chars.
3.5. Traffic Description Sub-TLVs
A Traffic Description Sub-TLV describes the traffic to be imported
into a BIER-TE path. Two Traffic Description Sub-TLVs are defined.
They are multicast traffic sub-TLVs for IPv4 and IPv6.
The multicast traffic sub-TLVs for IPv4 and IPv6 are shown in
Figure 5 and Figure 6 respectively.
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 (TBD5) | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |S|G| Src Mask Len | Grp Mask Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Address (up to 4 bytes) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Multicast Address (up to 4 bytes) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Multicast Traffic for IPv4 Sub-TLV
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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 (TBD6) | Length | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |S|G| Src Mask Len | Grp Mask Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Address ~
~ (up to 16 bytes) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group multicast Address ~
~ (up to 16 bytes) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Multicast Traffic for IPv6 Sub-TLV
The address fields and address mask lengths of the two Multicast
Traffic sub-TLVs contain source and group prefixes for matching
against packets noting that the two address fields are up to 32 bits
for an IPv4 Multicast Traffic and up to 128 bits for an IPv6
Multicast Traffic.
The Reserved field MUST be set to zero and ignored on receipt.
Two bit flags (S and G) are defined to describe the multicast
wildcarding in use. If the S bit is set, then source wildcarding is
in use and the values in the Source Mask Length and Source Address
fields MUST be ignored. If the G bit is set, then group wildcarding
is in use and the values in the Group Mask Length and Group multicast
Address fields MUST be ignored. The G bit MUST NOT be set unless the
S bit is also set: if a Multicast Traffic sub-TLV is received with S
bit = 0 and G bit = 1 the receiver MUST respond with an error
(Malformed Multicast Traffic).
The three multicast mappings may be achieved as follows:
(S, G): S bit = 0, G bit = 0, the Source Address and Group multicast
Address prefixes are both used to define the multicast traffic.
(*, G): S bit = 1, G bit = 0, the Group multicast Address prefix is
used to define the multicast traffic, but the Source Address
prefix is ignored.
(*, *): S bit = 1, G bit = 1, the Source Address and Group multicast
Address prefixes are both ignored.
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4. Security Considerations
Protocol extensions defined in this document do not affect the BGP
security other than those as discussed in the Security Considerations
section of [RFC9012].
5. Acknowledgements
The authors of this document would like to thank Tony Przygienda,
Susan Hares, and Jeffrey Zhang for their comments.
6. IANA Considerations
6.1. Existing Registry: SAFI Parameters
This document requests assigning a new SAFI in the registry
"Subsequent Address Family Identifiers (SAFI) Parameters" as follows:
+=======================+=========================+=============+
| Code Point | Description | Reference |
+=======================+=========================+=============+
| TBD1(179 suggested) | BIER-TE Policy SAFI |This document|
+=======================+=========================+=============+
6.2. Existing Registry: BGP TEA Tunnel Types
This document requests assigning a new Tunnel-Type in the registry
"BGP Tunnel Encapsulation Attribute Tunnel Types" as follows:
+=======================+=========================+=============+
| Code Point | Description | Reference |
+=======================+=========================+=============+
| TBD2(16 suggested) | BIER-TE Tunnel/Path |This document|
+=======================+=========================+=============+
6.3. Existing Registry: BGP TEA sub-TLVs
This document requests assigning a few of new sub-TLVs in the
registry "BGP Tunnel Encapsulation Attribute sub-TLVs" as follows:
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+=======================+=========================+=============+
| Code Point | Description | Reference |
+=======================+=========================+=============+
| TBD3(16 suggested) | Path BitStrings |This document|
+=======================+=========================+=============+
| TBD4(17 suggested) | Path Name |This document|
+=======================+=========================+=============+
| TBD5(18 suggested) | IPv4 Multicast Traffic |This document|
+=======================+=========================+=============+
| TBD6(19 suggested) | IPv6 Multicast Traffic |This document|
+=======================+=========================+=============+
7. References
7.1. 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,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
Encodings and Procedures for Multicast in MPLS/BGP IP
VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,
<https://www.rfc-editor.org/info/rfc6514>.
[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>.
[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>.
[RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
for Bit Index Explicit Replication (BIER) in MPLS and Non-
MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
2018, <https://www.rfc-editor.org/info/rfc8296>.
[RFC9012] Patel, K., Van de Velde, G., Sangli, S., and J. Scudder,
"The BGP Tunnel Encapsulation Attribute", RFC 9012,
DOI 10.17487/RFC9012, April 2021,
<https://www.rfc-editor.org/info/rfc9012>.
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7.2. Informative References
[I-D.ietf-bier-te-arch]
Eckert, T., Menth, M., and G. Cauchie, "Tree Engineering
for Bit Index Explicit Replication (BIER-TE)", draft-ietf-
bier-te-arch-13 (work in progress), April 2022.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<https://www.rfc-editor.org/info/rfc5575>.
Appendix A. Extensions to PMSI_TUNNEL Attribute
This section defines a new Tunnel Type (or TLV) for BIER-TE path/
tunnel under the PMSI_TUNNEL Attribute (PTA) defined in [RFC6514].
It describes a couple of new sub-TLVs encoding the information about
a BIER-TE path.
A.1. New Tunnel Type for BIER-TE
The PMSI Tunnel attribute carried by an x-PMSI A-D route identifies
P-tunnel for PMSI. For the PTA with Tunnel Type BIER-TE, the PTA is
constructed by the SDN controller and distributed to the ingress node
of the BIER-TE tunnel.
The format of the PMSI_TUNNEL Attribute with the new Tunnel Type
(TBD) for BIER-TE is shown in Figure 7.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attr Flags | Attr Type(22) | Length(1/2 byte) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flag |TunnelType(TBD)| MPLS Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MPLS Label | Tunnel Identifier (11/23 bytes) |
+-+-+-+-+-+-+-+-+ +
| ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs ~
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: PTA with Tunnel Type for BIER-TE
For BIER-TE tunnel/path, the fields in the PTA are set as follows:
o Tunnel Type: It is set to be TBD, indicating BIER-TE tunnel.
o Tunnel Identifier: It contains: sub-domain-id of 1 byte, BIER-TE
tunnel BFIR's BFR-id of 2 bytes, Tunnel-ID of 4 bytes, and
BIER-TE tunnel BFIR's BFR-prefix of 4/16 bytes for IPv4/IPv6.
o sub-TLVs: It contains a Path BitPositions sub-TLV encoding an
explicit BIER-TE path. It may include a Path Name sub-TLV for
the name of the BIER-TE path.
o Others: The other fields are set according to [RFC6514].
Authors' Addresses
Huaimo Chen
Futurewei
Boston, MA
USA
Email: huaimo.chen@futurewei.com
Mike McBride
Futurewei
Email: michael.mcbride@futurewei.com
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Ran Chen
ZTE Corporation
Email: chen.ran@zte.com.cn
Gyan S. Mishra
Verizon Inc.
13101 Columbia Pike
Silver Spring MD 20904
USA
Phone: 301 502-1347
Email: gyan.s.mishra@verizon.com
Aijun Wang
China Telecom
Beiqijia Town, Changping District
Beijing 102209
China
Email: wangaj3@chinatelecom.cn
Yisong Liu
China Mobile
Email: liuyisong@chinamobile.com
Yanhe Fan
Casa Systems
USA
Email: yfan@casa-systems.com
Boris Khasanov
Yandex LLC
Moscow
Email: bhassanov@yahoo.com
Chen, et al. Expires January 7, 2023 [Page 15]
Internet-Draft BIER-TE Path July 2022
Lei Liu
Fujitsu
USA
Email: liulei.kddi@gmail.com
Xufeng Liu
IBM Corporation
USA
Email: xufeng.liu.ietf@gmail.com
Chen, et al. Expires January 7, 2023 [Page 16]
