OSPF Extensions for BIER-TEFutureweiBoston, MAUSAHuaimo.chen@futurewei.comFutureweimichael.mcbride@futurewei.comChina TelecomBeiqijia Town, Changping DistrictBeijing102209Chinawangaj3@chinatelecom.cnVerizon Inc.13101 Columbia PikeSilver SpringMD 20904USA 301 502-1347gyan.s.mishra@verizon.comCasa SystemsUSAyfan@casa-systems.comFujitsuUSAliulei.kddi@gmail.comAlef EdgeUSAxufeng.liu.ietf@gmail.comThis document describes OSPFv2 and OSPFv3 extensions for distributing
the BitPositions configured on a Bit-Forwarding Router (BFR)
in a "Bit Index Explicit Replication Traffic Engineering"
(BIER-TE) domain.
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
when, and only when, they appear in all capitals, as shown here. introduces Bit Index
Explicit Replication (BIER) Traffic/Tree Engineering (BIER-TE).
It is an architecture for per-packet stateless explicit
point to multipoint (P2MP) multicast path/tree.
There are three types of BitPositions (BPs) in a BIER-TE domain:
link BitPosition (BP), routed BP and localdecap BP.
A link BP is a BP configured on a link from
Bit-Forwarding Router (BFR) X to BFR Y
for a forward connected adjacency from X to Y.
A routed BP is a BP configured on BFR X
for a forward routed adjacency from X to a remote BFR Z
not directly connected to X.
A localdecap BP is a BP configured on a BFR.
describes OSPFv2 Extensions for distributing
the BFR identifier (BFR-id) configured on a BFR.
describes OSPFv3 Extensions for distributing
the BFR identifier (BFR-id) configured on a BFR.
This document specifies OSPFv2 and OSPFv3 extensions for distributing
the BitPositions configured a BFR
in a BIER-TE domain.
The BitPositions distributed may be used
by a BFR as a Point of Local Repair (PLR) for
Fast-ReRoute (FRR).This section describes protocol extensions to OSPFv2
for distributing
the BitPositions configured on a BFR in
a BIER-TE domain.This section defines a Sub-TLV for distributing a link
BitPosition (BP). defines the OSPFv2 Extended Link TLV
to advertise the information about a link.
Only one OSPFv2 Extended Link TLV SHALL be advertised in each OSPFv2
Extended Link Opaque LSA.
The OSPFv2 Extended Link TLV has the following format:
1.Variable, dependent on Sub-TLVs.
They are defined in Section A.4.2 of
.MUST be set to 0 on transmission and MUST
be ignored on reception.
Under the OSPFv2 Extended Link TLV for a link,
a Sub-TLV, called Link-BP Sub-TLV, is
defined for distributing a link BitPosition.
A Link-BP Sub-TLV is included in the Link TLV for a link of
Link Type P2P (Point-to-Point) or Broadcast
(or say LAN or Transit Network).
The Link-BP Sub-TLV has the following format:
TBD1 is to be assigned by IANA.Variable.They are defined in
Section 2.1 of .A 2-octet field encoding the BitPosition
locally configured on the link/interface when the Link Type of
the link in the OSPFv2 Extended Link TLV containing this Sub-TLV
is 1 (i.e., Point-to-Point connection to another router) or
2 (i.e., connection to Transit Network or say LAN).
A 2-octet field encoding the BitPosition
of the connection on the designated router (DR) end. This field
exists when the Link Type in the OSPFv2 Extended Link TLV
containing this Sub-TLV is 2 (i.e., Transit Network or LAN).
For the other value of the Link Type, this field MUST NOT exist. The
DrEndBitPosition may be configured on
the link/interface to a transit network
(i.e., broadcast link or say LAN) as described in
.A TLV, called Node BPs TLV, is defined within
the body of the OSPF Router Information (RI) Opaque
Link State Advertisement (LSA) .
The TLV contains Sub-TLVs. Two types of Sub-TLVs are defined.
One is for a Routed BitPosition and
the other for a Localdecap BitPosition.The Node BPs TLV has the following format:
TBD2 is to be assigned by IANA.Variable.They are defined in
Section 2.1 of .They are Routed-BP Sub-TLVs for Routed BPs
and/or Localdecap-BP Sub-TLV for Localdecap BP.The Routed-BP Sub-TLV has the following format:
1 is the type for routed BP.It is 4.A 2-octet field encoding the BitPosition
configured on a BFR for a forward routed adjacency to a remote BFR.
A 2-octet field encoding the BFR-id of
the remote BFR.The Localdecap-BP Sub-TLV has the following format:
2 is the type for localdecap BP.It is 2.A 2-octet field encoding the
localdecap BitPosition configured on a BFR.This section describes protocol extensions to OSPFv3
for distributing the BitPositions configured on a BFR in
a BIER-TE domain. defines OSPFv3 Extended Router LSA,
which may include multiple Router-Link TLVs.
A Router-Link TLV defines a single router link.
A Router-Link TLV
may include a Link-BP Sub-TLV below
for distributing a link BP.
TBD3 is to be assigned by IANA. Variable.They are defined in
Section 2.1 of .A 2-octet field encoding the BitPosition
locally configured on the link/interface when the Link Type of
the link in the Router-Link TLV containing this Sub-TLV
is 1 (i.e., Point-to-Point connection to another router) or
2 (i.e., connection to Transit Network or say LAN).
A 2-octet field encoding the BitPosition
of the connection on the designated router (DR) end. This field
exists when the Link Type in the Router-Link TLV
containing this Sub-TLV is 2 (i.e., Transit Network or LAN).
For the other value of the Link Type, this field MUST NOT exist. The
DrEndBitPosition may be configured on
the link/interface to a transit network
(i.e., broadcast link or say LAN) as described in
.The Node BPs TLV, Routed BP Sub-TLV and Localdecap BP Sub-TLV
defined in
are reused in OSPVv3 for distributing the routed BitPositions
and the localdecap BitPosition configured on a BFR.
Protocol extensions defined in this document do not
affect the OSPF security other than those as discussed
in the Security Considerations section of
and .Under "OSPFv2 Extended Link TLV Sub-TLVs" registry as defined
in , IANA is
requested to assign a new registry value for
Link-BP Sub-TLV as follows:
+==============+===================+=====================+
| Value | Description | reference |
+==============+===================+=====================+
| TBD1 (25) | Link-BP | This document |
+--------------+-------------------+---------------------+
Under "OSPF Router Information (RI) TLVs" registry as defined
in , IANA is
requested to assign a new registry value for
Node BPs TLV as follows:
+==============+===================+=====================+
| Value | Description | reference |
+==============+===================+=====================+
| TBD2 (21) | Node BPs | This document |
+--------------+-------------------+---------------------+
IANA is requested to create a new subregistry called the
"OSPF Node BPs Sub-TLVs" under the
"Open Shortest Path First (OSPF) Parameters" registry.
The initial values are as follows:
+===========+===================+========================+
| Value | Description | reference |
+===========+===================+========================+
| 0 | Reserved | This document |
+-----------+-------------------+------------------------+
| 1 | Routed BP | This document |
+-----------+-------------------+------------------------+
| 2 | Localdecap BP | This document |
+-----------+-------------------+------------------------+
| 3 - 65535 | To be allocated in First Come First Served|
+-----------+-------------------+------------------------+
Under "OSPFv3 Extended-LSA Sub-TLVs" registry as defined
in , IANA is
requested to assign a new registry value for
Link-BP Sub-TLV as follows:
+==============+===================+=====================+
| Value | Description | reference |
+==============+===================+=====================+
| TBD3 (30) | Link-BP | This document |
+--------------+-------------------+---------------------+
AcknowledgmentsThe authors would like to thank Acee Lindem, Les Ginsberg,
Tony Przygienda, Jeffrey Zhang and
Toerless Eckert for their comments on this work.