Internet DRAFT - draft-li-pce-based-bier
draft-li-pce-based-bier
PCE Working Group H. Li
Internet-Draft A. Wang
Intended status: Standards Track China Telecom
Expires: April 22, 2022 H. Chen
Futurewei
R. Chen
ZTE Corporation
October 19, 2021
PCE based BIER Procedures and Protocol Extensions
draft-li-pce-based-bier-02
Abstract
This document describes extensions to Path Computation Element (PCE)
communication Protocol (PCEP) for supporting the PCE based Bit Index
Explicit Replication (BIER) deployment.
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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This Internet-Draft will expire on April 22, 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Overview of PCE based BIER solution . . . . . . . . . . . . . 4
4.1. Example of PCE based BIER Topology . . . . . . . . . . . 4
4.2. Basic Procedures . . . . . . . . . . . . . . . . . . . . 5
5. Capability Advertisement . . . . . . . . . . . . . . . . . . 5
6. PCEP message . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. PCRpt message . . . . . . . . . . . . . . . . . . . . . . 6
6.2. PCUpd message . . . . . . . . . . . . . . . . . . . . . . 7
7. Object formats . . . . . . . . . . . . . . . . . . . . . . . 8
7.1. Multicast Source Registration Object . . . . . . . . . . 8
7.1.1. Multicast Source Address TLV . . . . . . . . . . . . 9
7.1.2. BIER Information TLV . . . . . . . . . . . . . . . . 10
7.1.3. VPN Information TLV . . . . . . . . . . . . . . . . . 10
7.2. Multicast Receiver Information Object . . . . . . . . . . 11
7.2.1. Multicast Group Address TLV . . . . . . . . . . . . . 12
7.3. Forwarding Indication Object . . . . . . . . . . . . . . 12
7.4. Multicast Receiver Status Object . . . . . . . . . . . . 13
8. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Multicast source registration and revocation . . . . . . 14
8.2. Joining and leaving of multicast receivers . . . . . . . 15
8.3. BitString management . . . . . . . . . . . . . . . . . . 15
8.4. Receiver information synchronization . . . . . . . . . . 15
9. Deployment Considerations . . . . . . . . . . . . . . . . . . 16
10. Security Considerations . . . . . . . . . . . . . . . . . . . 16
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
11.1. BIER-MULTICAST-CAPABILITY . . . . . . . . . . . . . . . 16
11.2. PCEP-ERROR Object . . . . . . . . . . . . . . . . . . . 16
11.3. New Objects . . . . . . . . . . . . . . . . . . . . . . 16
11.4. New TLVs . . . . . . . . . . . . . . . . . . . . . . . . 16
12. Contributor . . . . . . . . . . . . . . . . . . . . . . . . . 17
13. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 17
14. Normative References . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
[RFC8279] defines a Bit Index Explicit Replication (BIER)
architecture where all intended multicast receivers are encoded as a
bitmask in the multicast packet header within different
encapsulations such as described in [RFC8296] . A router that
receives such a packet will forward the packet based on the bit
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position in the packet header towards the receiver(s) following a
precomputed tree for each of the bits in the packet. Each receiver
is represented by a unique bit in the bitmask.
Currently, multicast management information is mainly signaled by PIM
[RFC2362] or BGP [RFC6514], which have some limitations in the
deployment and process.
[RFC4655] defines a stateful PCE to be one in which the PCE maintains
"strict synchronization between the PCE and not only the network
states (in term of topology and resource information), but also the
set of computed paths and reserved resources in use in the network."
[RFC8231] specifies a set of extensions to PCEP to support state
synchronization between PCCs and PCEs.
This document specifies PCEP protocol extensions to optimize the
implementation of multicast source registration or revocation,
receiver automatic discovery, and forwarding control of multicast
data by using PCEP messages to transmit multicast management
signaling, combining with the forwarding characteristics of BIER.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Terminology
The following terms are used in this document:
o BFR-id: BFR Identifier. It is a number in the range [1,65535]
o BGP: Border Gateway Protocol
o BIER: Bit Index Explicit Replication
o BIFT: Bit Index Forwarding Table
o FI: Forwarding indication
o IGMP: Internet Group Management Protocol
o IGP: Interior Gateway Protocols
o MLD: Multicast Listener Discover
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o MRI: Multicast Receiver Information
o MSR: Multicast Source Registration
o PCC: Path Computation Client
o PCE: Path Computation Element
o PCEP: PCE communication Protocol
o PIM: Protocol Independent Multicast
4. Overview of PCE based BIER solution
PCE based BIER includes multicast source registration information
management, multicast receiver information management and multicast
data forwarding control.
Multicast source registration information includes registration and
processing of multicast source information.
Multicast receiver information includes requesting multicast group,
multicast source and BitPosition information of receiver-side PCC.
Multicast data forwarding control includes BitString processing and
data forwarding.
PCRpt message and PCUpd message, described in [RFC8231], are used in
the PCE based BIER processing.
This document specifies PCEP protocol extensions for multicast group
management, including Multicast Source Registration (MSR) object,
Multicast Receiver Information (MRI) object, Forwarding Indication
(FI) object and Multicast Receiver Status(MRS) object.
4.1. Example of PCE based BIER Topology
An example of PCE based BIER topology for a BIER domain with a
controller as PCE is shown in Figure 1. In this domain, node R1 and
R7 are Bit-Forwarding Ingress Router (BFIR) and Bit-Forwarding Egress
Router (BFER), respectively.
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+------------------+
+ Controller +
+-----------+ PCE +---------+
| +--------^---------+ |
| |
| |
S1|S2/S5 +--------+ |S4
| -----------+ R3 +----------- |
| / +--------+ \ |
| / \ |
+------+ +--+ S6 +--+ +--+ +--+ S3 +--------+
|Source|----|R1+----------+R5+----------+R6+--------+R7|-----|Receiver|
+------+ +--+ +--+ +--+ +--+ +--------+
| |
| +--+ +--+ |
+-----------+R2+----------+R4+-----------+
+--+ +--+
Figure 1: Example of PCE based BIER Topology(controller as PCE)
4.2. Basic Procedures
Step 1(S1): R1 sends multicast source information and authentication
information to the controller about multicast information
registration via PCRpt message.
Step 2(S2): The controller sends PCUpd message to R1, carrying
authentication result.
Step 3(S3): Receivers send IGMP or MLD messages to R7 requesting to
join or leave a multicast group.
Step 4(S4): R7 converts the IGMP or MLD messages into PCRpt message
and sends it to the controller.
Step 5(S5): If the multicast group and multicast source information
requested by the receiver has registered, the controller will send
PCUpd message to R1 to start or stop forwarding, carrying BitString.
Step 6(S6): If R1 is ready to start forwarding, it will encapsulate
BIER header and forward them based on BIFT and BitString when
receiving multicast packets.
5. Capability Advertisement
During the PCEP initialization phase, PCEP speakers advertise
stateful capability via the STATEFUL-PCE-CAPABILITY TLV in the OPEN
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object. Various flags are defined for the STATEFUL-PCE-CAPABILITY
TLV defined in [RFC8231] and updated in[RFC8232] and [RFC8281].
A new flag is added in this document, whose code point is TBD1:
B (BIER-MULTICAST-CAPABILITY, 1 bit): If set to 1 by a PCEP speaker,
it indicates that the PCEP speaker supports the capability of these
new flag as specified in this document.
If a PCEP speaker receivers PECP message with the newly defined
object, but without the B bit set in STATEFUL-PCE-CAPABILITY TLV in
the OPEN object, it MUST:
o Send a PCErr message with Error-Type=10(Reception of an invalid
object) and Error-Value TBD2(BIER-MULTICAST-CAPABILITY bit is not
set).
o Terminate the PCEP session.
6. PCEP message
6.1. PCRpt message
MSR objectSection 7.1 should be included in the PCRpt message when
PCC registers multicast source information with PCE.
MRI objectSection 7.2 should be included in the PCRpt message when
PCC sends multcast join messages to PCE.
MRS objectSection 7.4 should be included in the PCRpt message when
PCC inform PCE of the number of receivers.
The definition of the PCRpt message from [RFC8231] is extended to
optionally include MSR object, MRI object and MRS object after the
path object. The encoding from [RFC8231] will become:
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<PCRpt Message> ::= <Common Header>
<state-report-list>
Where:
<state-report-list> ::= <state-report>[<state-report-list>]
<state-report> ::= [<SRP>]
<LSP>
<path>
[<MSR>]
[<MRI>]
[<MRS>]
Where:
<path> is as per [RFC8231] and the LSP and SRP object are
also defined in [RFC8231].
6.2. PCUpd message
MSR objectSection 7.1 should be included in the PCUpd message when
PCE responds to the registration request.
FI objectSection 7.3 should be included in the PCUpd message when PCE
sends the BitString to PCC to indicate the path of multicast data
packets forwarding for PCC.
MRS objectSection 7.4 should be included in the PCUpd message when
PCE inform PCC of the number of receivers.
The definition of the PCUpd message from [RFC8231] is extended to
optionally include MSR object, FI object and MRS object after the
path object. The encoding from [RFC8231] will become:
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<PCUpd Message> ::= <Common Header>
<update-request-list>
Where:
<update-request-list> ::= <update-request>[<update-request-list>]
<update-request> ::= <SRP>
<LSP>
<path>
[<MSR>]
[<FI>]
[<MRS>]
Where:
<path> is as per [RFC8231] and the LSP and SRP object are
also defined in [RFC8231].
7. Object formats
7.1. Multicast Source Registration Object
The MSR object is optional and specifies multicast source information
in multicast registration information management. The MSR object
should be carried within a PCRpt message sent by PCC to PCE for
registration. The MSR object should be carried within a PCUpd
message sent by PCE to PCC in response to registration.
MSR Object-Class is TBD3. MSR Object-Type is 1.
The format of the MSR object body is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flags |B|R|A|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auxliary Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Auxiliary Data ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Optional TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: MSR Object Body Format
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B(BIER multicast flag, 1 bit): The R flag set to 1 indicates that
multicast protocol is BIER. The R flag set to 0 indicates that
multicast protocol is not BIER.
R (Register flag, 1 bit): The R flag set to 1 indicates that the PCC
is registering multicast information to the PCE. The R flag set to 0
indicates that the PCC revokes the register.
A (Authentication flag, 1 bit): The A flag set to 1 indicates success
of registration. The A flag set to 0 indicates failure of
registration or cancellation of registration. R and A cannot both be
set to 0 or 1 in PCRpt message.
Auxiliary Length(8 bits): indicates the length of Auxiliary Data.
Auxiliary Data(Variable length): contains functional data such as
authentication information.
MSR object could include three types of TLVs, namely Multicast Source
Address TLV, BIER Information TLV, VPN Information TLV, as defined
follows:
7.1.1. Multicast Source Address TLV
The format of the Multicast Source Address TLV is:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Multicast Source Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Multicast Source Address TLV Format
Type(16 bits): TBD4 is to be assigned by IANA.
Length: Variable.
Prefix Length(16 bits): indicates the length of multicast source
address.
Multicast Source Address(Variable length): contains IPv4 or IPv6
address of the multicast source.
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7.1.2. BIER Information TLV
BIER Information TLV is used to report router location information in
the BIER domain. When the multicast flag in MSR, MRI, FI objects is
set, BIER Information TLV should be included. The format of the BIER
Information TLV is:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subdomain-id | BFR-ID | BSL | Res |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: BIER Information TLV Format
Type(16 bits): TBD5 is to be assigned by IANA.
Length: Variable.
Subdomain-id(8 bits): Unique value identifying the BIER subdomain.
BFR-ID (16 bits): Identification of BFR in a subdomain.
BSL(BitString Length, 4 bits): encodes the length in bits of the
BitString as per[RFC8296] , the maximum length of the BitString is 7,
it indicates the length of BitString is 4096. It is used to refer to
the number of bits in the BitString.
7.1.3. VPN Information TLV
VPN Information TLV is used to report VPN information about multicast
sources and receivers. When the multicast flag in MSR, MRI, FI
objects is set, VPN Information TLV should be included. The format
of the VPN Information TLV is:
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RD |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Forwarding Label ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: VPN Information TLV Format
Type(16 bits): TBD6 is to be assigned by IANA.
Length: Variable.
RD(Route Distinguisher, 8 bytes): indicates the VPN which the
receiver used.
Label Length(16 bits): indicates the length of forwarding label Data,
the length should be 0 ,32 bits or 128 bits.
Forwarding Label(Variable Length): contains MPLS label with 32 bit or
IPv6 Segment Identifier with 128 bits.
7.2. Multicast Receiver Information Object
The MRI object is optional and specifies receivers' information for
matching the multicast registration information. The MRI object
should be carried within a PCRpt message sent by PCC to PCE in
muticast joining or leaving.
MRI Object-Class is TBD7. MRI Object-Type is 1.
The format of the MRI object body is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flags |B|S| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Optional TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: MRI Object Body Format
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B(BIER multicast flag, 1 bit): The R flag set to 1 indicates that
multicast protocol is BIER. The R flag set to 0 indicates that
multicast protocol is not BIER.
S(Subscribe flag, 1 bit): The S flag set to 1 indicates that PCC
delivers the message requesting to join PCE. The S flag set to 0
indicates that PCC delivers the message requesting to leave to PCE.
MRI object could include four types of TLVs, namely Multicast Source
Address TLVSection 7.1.1, BIER INFO TLVSection 7.1.2, VPN Information
TLVSection 7.1.3 and Multicast Group Address TLV. Multicast Group
Address TLV is defined as follows:
7.2.1. Multicast Group Address TLV
The format of the Multicast Group Address TLV is:
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 = TBD8 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Multicast Group Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Multicast Group Address TLV Format
Type(16 bits): TBD8 is to be assigned by IANA.
Length: Variable.
Prefix Length(16 bits): indicates the length of multicast group
address.
Multicast Group Address(Variable length): contains IPv4 or IPv6
address of the multicast group.
7.3. Forwarding Indication Object
The FI object is optional and used to indicate to the headend how to
forward multicast data packets in the form of BitString. The FI
object should be carried within a PCUpd message sent by PCE to PCC in
multicast scenarios.
FI Object-Class is TBD9. FI Object-Type is 1.
The format of the FI object body is:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subdomain-id | SI | BSL | Reserved |B|F|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitString (first 32 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . |
| . |
| . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitString (last 32 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Optional TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: FI Object Body Format
Subdomain-id(8 bits): Unique value identifying the BIER subdomain.
SI (Set Identifier, 8 bits): encoding the Set Identifier used in the
encapsulation for this BIER subdomain for this BitString length..
BSL(BitString Length, 4 bits): encodes the length in bits of the
BitString as per[RFC8296] , the maximum length of the BitString is 7,
it indicates the length of BitString is 4096. It is used to refer to
the number of bits in the BitString.
B(BIER multicast flag, 1 bit): The R flag set to 1 indicates that
multicast protocol is BIER. The R flag set to 0 indicates that
multicast protocol is not BIER.
F(Forwarding flag, 1 bit): The F flag set to 1 indicates that the
router may start forwarding multicast packets. The F flag set to 0
indicates that the router should stop forwarding multicast packets.
BitString(Variable length): indicates the path of multicast data
packets forwarding for headend.
FI object should include three types of TLVs, namely Multicast Source
Address TLVSection 7.1.1, VPN Information TLVSection 7.1.3 and
Multicast Group Address TLVSection 7.2.1.
7.4. Multicast Receiver Status Object
The MRS object is optional and used to inform PCE of the number of
receivers. The MRS object should be carried within a PCRpt or a
PCUpd message for synchronize receiver information periodically, or
PCRpt message for the leaving of receivers.
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MRS Object-Class is TBD10. MRS Object-Type is 1.
The format of the MRS object body is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Receivers |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Optional TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: MRS Object Body Format
Number Length(16 bits): indicates the length of receiver number.
Number of Receivers(32 bits): indicates the number of receivers for a
particular (S,G) tuple.
MRS object should include two types of TLVs, namely Multicast Source
Address TLVSection 7.1.1 and Multicast Group Address
TLVSection 7.2.1.
8. Procedures
8.1. Multicast source registration and revocation
For PCC-Registered multicast source, an ingress node sends a PCRpt
message with MSR object to a stateful PCE, where R flag is set and A
flag is not set. The registered authentication information can be
passed through auxiliary data in MSR object.
Upon receiving the registration via PCRpt message, the stateful PCE
MUST match local authentication rules based on the multicast
information and auxiliary data in PCRpt message. If authenticated
successfully, the PCE stores the multicast registration information
into the database. In response, PCE MUST send a PCUpd message with
MSR object to ingress node, where R flag is set. A flag is set only
if authentication is successful.
For PCC-revoked multicast source registration, an ingress node sends
a PCRpt message with MSR object to a stateful PCE, where R flag is
not set and A flag is set.
Upon receiving the revocation via PCRpt message, in response, PCE
MUST send a PCUpd message with MSR object to ingress node, where
neither R nor A is set.
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8.2. Joining and leaving of multicast receivers
When an egress node receives an IGMP or MLD message from a multicast
receiver to join, the egress node should send a PCRpt message with
MRI object to the PCE if no other receiver has sent the same request
to it before.
If it is not the first time the PCE has received the same PCRpt
message for join from the same egress node, this message should be
ignored.
When an egress node receives an IGMP or MLD message from a multicast
receiver to leave, the egress node should send a PCRpt message with
MRI object and MRS object to the PCE if there are no other members in
the requested multicast group. In MRS object, the number of
receivers is zero.
8.3. BitString management
Upon receiving the join or leave request via PCRpt message, PCE needs
to combine the BFR-id and SI of the egress node carried in PCRpt
message with the BFR-id and SI of the ingress node and existed
BitStrings in the database to create or update BitString. If there
are members in the multicast group, the PCE should send a PCUpd
message with FI object carrying the latest BitString to the ingress
node, where F flag is set.
When receving multicast packets, the ingress node encapsulates BIER
header and forwards them based on BIFT and BitString. Encapsulation
of Forwarding Label is not in the scope of this document.
If there is no member in the multicast group, the PCE should send a
PCUpd message with FI object to the ingress node, where F flag is not
set.
8.4. Receiver information synchronization
Upon receiving multicast packets from a particular multicast group,
egress node will synchronize the number of receivers in this
multicast group with the PCE via PCRpt message with MRS object
periodically.
After sending a PCUpd message with FI object to an ingress node for a
particular multicast group, the PCE will synchronize the total number
of receivers in this multicast group with the ingress node via PCUpd
message with MRS object periodically.
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If there is no member in the multicast group, the synchronization of
receiver number information ends.
9. Deployment Considerations
10. Security Considerations
11. IANA Considerations
11.1. BIER-MULTICAST-CAPABILITY
IANA is requested to allocate a new code point within registry
"STATEFUL-PCE-CAPABILITY TLV Flag Field" under "Path Computation
Element Protocol (PCEP) Numbers" as follows:
Value Description Reference
------------ ----------------------------- ---------------
TBD1 BIER-MULTICAST-CAPABILITY This document
11.2. PCEP-ERROR Object
IANA is requested to allocate code-points in the "PCEP-ERROR Object
Error Types and Values" subregistry for the following new error-type
and error-value:
Error-Type Description Reference
------------ ----------------------------- ---------------
10 Error-value = TBD2 This document
B bit is not set
11.3. New Objects
IANA is requested to allocate the following Object-Class Values in
the "PCEP Objects" subregistry under the "Path Computation Element
Protocol (PCEP) Numbers" registry:
Object-Class Value Description Reference
------------------- ------------------------------ ---------------
TBD3 Multicast Receiver Information This document
TBD7 Multicast Receiver Information This document
TBD9 Forwarding Indication This document
TBD10 Multicast Receiver Status This document
11.4. New TLVs
IANA is requested to allocate the following Object-Class Values in
the "PCEP Objects" subregistry under the "Path Computation Element
Protocol (PCEP) Numbers" registry:
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Type Description Reference
------------------- ------------------------------ ---------------
TBD4 Multicast Source Address This document
TBD5 Multicast Group Address This document
TBD6 BIER Information TLV This document
TBD8 VPN Information This document
12. Contributor
13. Acknowledgement
14. 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>.
[RFC2362] Estrin, D., Farinacci, D., Helmy, A., Thaler, D., Deering,
S., Handley, M., Jacobson, V., Liu, C., Sharma, P., and L.
Wei, "Protocol Independent Multicast-Sparse Mode (PIM-SM):
Protocol Specification", RFC 2362, DOI 10.17487/RFC2362,
June 1998, <https://www.rfc-editor.org/info/rfc2362>.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>.
[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>.
[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/info/rfc8231>.
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[RFC8232] Crabbe, E., Minei, I., Medved, J., Varga, R., Zhang, X.,
and D. Dhody, "Optimizations of Label Switched Path State
Synchronization Procedures for a Stateful PCE", RFC 8232,
DOI 10.17487/RFC8232, September 2017,
<https://www.rfc-editor.org/info/rfc8232>.
[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>.
[RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for PCE-Initiated LSP Setup in a Stateful PCE
Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
<https://www.rfc-editor.org/info/rfc8281>.
[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>.
Authors' Addresses
Huanan Li
China Telecom
Beiqijia Town, Changping District
Beijing, Beijing 102209
China
Email: lihn6@foxmail.com
Aijun Wang
China Telecom
Beiqijia Town, Changping District
Beijing, Beijing 102209
China
Email: wangaj3@chinatelecom.cn
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Huaimo Chen
Futurewei
Boston
USA
Email: Huaimo.chen@futurewei.com
Ran Chen
ZTE Corporation
50 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: chen.ran@zte.com.cn
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