Internet Engineering Task Force (IETF) R. Parekh, Ed.
Request for Comments: 9960 Arrcus
Updates: 9524 D. Voyer, Ed.
Category: Standards Track C. Filsfils
ISSN: 2070-1721 Cisco Systems, Inc.
H. Bidgoli
Nokia
Z. Zhang
Juniper Networks
April 2026
Segment Routing Point-to-Multipoint Policy
Abstract
The Point-to-Multipoint (P2MP) Policy enables creation of P2MP trees
for efficient multipoint packet delivery in a Segment Routing (SR)
domain. This document specifies the architecture, signaling, and
procedures for SR P2MP Policies with Segment Routing over MPLS (SR-
MPLS) and Segment Routing over IPv6 (SRv6). It defines the SR P2MP
Policy construct, candidate paths (CPs) of an SR P2MP Policy, and the
instantiation of the P2MP tree instances (PTIs) of a CP using
Replication segments. Additionally, it describes the required
extensions for a controller to support P2MP path computation and
provisioning. This document updates RFC 9524.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9960.
Copyright Notice
Copyright (c) 2026 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
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Table of Contents
1. Introduction
1.1. Terminology
1.2. Requirements Language
2. SR P2MP Policy
2.1. SR P2MP Policy Identification
2.2. Components of an SR P2MP Policy
2.3. Candidate Paths and P2MP Tree Instances
3. Steering Traffic into an SR P2MP Policy
4. P2MP Tree Instance
4.1. Replication Segments at Leaf Nodes
4.2. Shared Replication Segments
4.3. Packet Forwarding in a P2MP Tree Instance
5. Using a Controller to Build a P2MP Tree
5.1. SR P2MP Policy on a Controller
5.2. Controller Functions
5.3. P2MP Tree Compute
5.4. SID Management
5.5. Instantiating P2MP Tree Instance on Nodes
5.6. Protection
5.6.1. Local Protection
5.6.2. Path Protection
6. IANA Considerations
7. Security Considerations
8. References
8.1. Normative References
8.2. Informative References
Appendix A. Illustration of the SR P2MP Policy and P2MP Tree
A.1. P2MP Tree with Non-Adjacent Replication Segments
A.1.1. SR-MPLS
A.1.2. SRv6
A.2. P2MP Tree with Adjacent Replication Segments
A.2.1. SR-MPLS
A.2.2. SRv6
Acknowledgements
Contributors
Authors' Addresses
1. Introduction
[RFC9524] defines a Replication segment that enables a Segment
Routing (SR) SR node to
replicate traffic to multiple downstream nodes in an SR domain
[RFC8402]. A Point-to-Multipoint (P2MP) service can be realized by a
single Replication segment spanning from the ingress node to the
egress nodes of the service. This effectively achieves ingress
replication, which is inefficient since the traffic of the P2MP
service may traverse the same set of nodes and links in the SR domain
on its path from the ingress node to the egress nodes.
A multipoint service delivery can be efficiently realized with a P2MP
tree in a Segment Routing SR domain. A P2MP tree spans from a Root node to a set of
Leaf nodes via intermediate Replication nodes. It consists of a
Replication segment at the Root node, and that Replication segment is
stitched to one or more Replication segments at between the Leaf nodes
and intermediate Replication nodes. A Bud node [RFC9524] is a node
that is both a Replication node and a Leaf node. Any mention of
"Leaf node(s)" in this document should be considered as referring to
"Leaf or Bud node(s)".
An SR P2MP Policy defines the Root and Leaf nodes of a P2MP tree. It
has one or more candidate paths (CPs) CPs provisioned with optional constraints and/or
optimization objectives.
A controller computes P2MP tree instances PTIs of the candidate paths CPs using the constraints and
objectives specified in the candidate path. CP. The controller then instantiates a P2MP tree instance
PTI in the SR domain by signaling Replication segments to the Root,
Replication, and Leaf nodes. A Path Computation Element (PCE)
[RFC4655] is one example of such a controller. In other cases, a P2MP tree instance PTI
can be installed using the Network Configuration Protocol (NETCONF) /
YANG or the Command Line Interface (CLI) on the Root, Replication,
and Leaf nodes.
The Replication segments of a P2MP tree instance PTI can be instantiated for SR-MPLS
[RFC8660] and SRv6 [RFC8986] data planes, enabling efficient packet
replication within an SR domain.
This document updates the Replication-ID portion of the Replication
segment identifier (Replication-SID) specified in Section 2 of
[RFC9524].
1.1. Terminology
This section defines terms used frequently in this document. Refer
to the Terminology section of [RFC9524] for the definitions of
Replication segment and other terms associated with it and the
definitions of Root, Leaf, and Bud nodes.
SR P2MP Policy: An SR P2MP Policy is a framework to construct P2MP
trees in an SR domain by specifying Root and Leaf nodes.
Tree-ID: An identifier of an SR P2MP Policy in context of the Root
node.
Candidate path (CP): A CP of the SR P2MP Policy defines topological
or resource constraints and optimization objectives that are used
to compute and construct P2MP tree instances. PTIs.
P2MP tree instance (PTI): A PTI of a candidate path CP is constructed by stitching
Replication segments between the Root and Leaf nodes of an SR P2MP
Policy. Its topology is determined by the constraints and
optimization objective of the candidate path. CP.
Instance-ID: An identifier of a P2MP tree instance PTI in context of the SR P2MP
Policy.
Tree-SID: The Replication-SID of the Replication segment at the Root
node of a P2MP tree instance. PTI.
1.2. Requirements Language
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.
2. SR P2MP Policy
An SR P2MP Policy is used to instantiate P2MP trees between Root and
Leaf nodes in an SR domain. Note that multiple SR P2MP Policies can
have identical Root nodes and identical sets of Leaf nodes. An SR
P2MP Policy has one or more candidate paths CPs [RFC9256].
2.1. SR P2MP Policy Identification
An SR P2MP Policy is uniquely identified by the tuple <Root, Tree-
ID>, where:
* Root: The IP address of the Root node of P2MP trees instantiated
by the SR P2MP Policy.
* Tree-ID: A 32-bit unsigned integer that uniquely identifies the SR
P2MP Policy in the context of the Root node.
2.2. Components of an SR P2MP Policy
An SR P2MP Policy consists of the following elements:
* Leaf nodes: A set of nodes that terminate the P2MP trees of the SR
P2MP Policy.
* Candidate paths: A set of possible paths that define constraints
and optimization objectives for P2MP tree instances PTIs of the SR P2MP Policy.
An SR P2MP Policy and its CPs are provisioned on a controller (see
Section 5) or the Root node or both, depending upon the provisioning
model. After provisioning, the Policy and its CPs are instantiated
on the Root node or the controller by using a signaling protocol.
2.3. Candidate Paths and P2MP Tree Instances
An SR P2MP Policy has one or more CPs. The tuple <Protocol-Origin,
Originator, Discriminator>, as specified in Section 2.6 of [RFC9256],
uniquely identifies a candidate path CP in the context of an SR P2MP Policy. The
semantics of Protocol-Origin, Originator, and Discriminator fields of
the identifier are the same as in Sections 2.3, 2.4, and 2.5 of
[RFC9256], respectively.
The Root node of the SR P2MP Policy selects the active candidate path CP based on
the tiebreaking rules defined in Section 2.9 of [RFC9256].
A CP may include topological and/or resource constraints and
optimization objectives that influence the computation of the PTIs of
the CP.
A candidate path CP has zero or more PTIs. A candidate path CP does not have a PTI when the
controller cannot compute a P2MP tree from the network topology based
on the constraints and/or optimization objectives of the CP. A candidate path CP
can have more than one PTI, e.g., during the Make-Before-Break (see
Section 5.3) procedure to handle a network state change. However,
one and only one PTI MUST be the active instance of the CP. If more
than one PTI of a CP is active at same time, and that CP is the
active CP of the SR P2MP Policy, then duplicate traffic may be
delivered to the Leaf nodes.
A PTI is identified by an Instance-ID. This is an unsigned 16-bit
number that is unique in context of the SR P2MP Policy of the
candidate path. CP.
PTIs are instantiated using Replication segments. Section 2 of
[RFC9524] specifies the Replication-ID of the Replication segment
identifier Replication-SID tuple
as a variable length field that can be modified as required based on
the use of a Replication segment. However, length is an imprecise
indicator of the actual structure of the Replication-
ID. Replication-ID. This
document updates the Replication-ID of a Replication
segment identifier Replication-SID [RFC9524] to
be the tuple: <Root, Tree-ID, Instance-ID, Node-ID>, where <Root,
Tree-ID> identifies the SR P2MP Policy and Instance-ID identifies the
PTI within that SR P2MP Policy. This results in the Replication
segments used to instantiate a PTI being identified by the tuple:
<Root, Tree-ID, Instance-ID, Node-ID>. In the simplest case, the
Replication-ID of a Replication segment is a 32-bit number as per
Section 2 of [RFC9524]. For this use case, [RFC9524] for which the Root MUST be zero (0.0.0.0 for
IPv4 and :: for IPv6) and IPv6), the Instance-ID MUST be zero zero, and the 32-bit
Tree-ID to effectively make the
Replication segment identifier Replication-SID <[0.0.0.0 or ::],
Tree-ID, 0, Node-
ID>. Node-ID>.
PTIs may have different tree topologies due to possibly differing
constraints and optimization objectives of the CPs in an SR P2MP
Policy and across different policies. Even within a given CP, two
PTIs of that CP, say during the Make-Before-Break procedure, are
likely to have different tree topologies due to a change in the
network state. Since the PTIs may have different tree topologies,
their replication states also differ at various nodes in the SR
domain. Therefore, each PTI has its own Replication segment and a
unique Replication-SID at a given node in the SR domain.
A controller designates an active instance of a CP at the Root node
of the SR P2MP Policy by signaling this state through the protocol
used to instantiate the Replication segment of the instance.
This document focuses on the use of a controller to compute and
instantiate PTIs of SR P2MP Policy CPs. It is also feasible to
provision an explicit CP in an SR P2MP Policy with a static tree
topology using NETCONF/YANG or CLI. Note that a static tree topology
will not adapt to any changes in the network state of an SR domain.
The explicit CPs may be provisioned on the controller or the Root
node. When an explicit CP is provisioned on the controller, the
controller bypasses the compute stage and directly instantiates the
PTIs in the SR domain. When an explicit CP is provisioned on the
Root node, the Root node instantiates the PTIs in the SR domain. The
exact procedures for provisioning an explicit CP and the signaling
from the Root node to instantiate the PTIs are outside the scope of
this document.
3. Steering Traffic into an SR P2MP Policy
The Replication-SID of the Replication segment at the Root node is
referred to as the Tree-SID of a PTI. It is RECOMMENDED that the
Tree-SID is also used as the Replication-SID for the Replication
segments at the intermediate Replication nodes and the Leaf nodes of
the PTI as it simplifies operations and troubleshooting. However,
the Replication-SIDs of the Replication segments at the intermediate
Replication nodes and the Leaf nodes MAY differ from the Tree-SID.
For SRv6, Replication-SID is the FUNCT portion of the SRv6 segment ID
(SID) [RFC8986] [RFC9524]. Note that even if the Tree-SID is the
Replication-SID of all the Replication segments of a PTI, the locator
(LOC) portion of the SRv6 SID [RFC8986] differs for the Root node,
the intermediate Replication nodes, and the Leaf nodes of the PTI.
An SR P2MP Policy has a Binding SID (BSID). The BSID is used to
steer traffic into an SR P2MP Policy, as described below, when the
Root node is not the ingress node of the SR domain where the traffic
arrives. The packets are steered from the ingress node to the Root
node using a segment list with the BSID as the last segment in the
list. In this case, it is RECOMMENDED that the BSID of an SR P2MP
Policy SHOULD be constant throughout the lifetime of the policy so
the steering of traffic to the Root node remains unchanged. The BSID
of an SR P2MP Policy MAY be the Tree-SID of the active P2MP instance
of the active CP of the policy. In this case, the BSID of an SR P2MP
Policy changes when the active CP or the active PTI of the SR P2MP
Policy changes. Note that the BSID is not required to steer traffic
into an SR P2MP Policy when the Root node of an SR P2MP Policy is
also the ingress node of the SR domain where the traffic arrives.
The Root node can steer an incoming packet into an SR P2MP Policy in
one of following methods:
* Local-policy-based forwarding: The Root node maps the incoming
packet to the active PTI of the active CP of an SR P2MP Policy
based on local forwarding policy, and it is replicated with the
encapsulated Replication-SIDs of the downstream nodes. The
procedures to map an incoming packet to an SR P2MP Policy are out
of scope of this document. It is RECOMMENDED that an
implementation provide a mechanism to examine the result of
application of the local forwarding policy, i.e., provide
information about the traffic mapped to an SR P2MP Policy and the
active CP and active PTI of the policy.
* Tree-SID-based forwarding: The Binding SID, BSID, which may be the Tree-
SID Tree-SID of
the active PTI, in an incoming packet is used to map the packet to
the active PTI. The Binding SID BSID in the incoming packet is replaced with
the Tree-SID of the active PTI of the active CP, and the packet is
replicated with the Replication-SIDs of the downstream nodes.
For local-policy-based forwarding with SR-MPLS, the TTL for the Root
node SHOULD set the TTL in the encapsulating MPLS header so that the
replicated packet can reach the furthest Leaf node. The Root MAY set
the TTL in the encapsulating MPLS header from the payload. In this
case, the TTL may not be sufficient for the replicated packet to
reach the furthest node. For SRv6, Section 2.2 of [RFC9524] provides
guidance to set the IPv6 Hop Limit of the encapsulating IPv6 header.
4. P2MP Tree Instance
A P2MP tree instance PTI within an SR domain establishes a forwarding structure that
connects a Root node to a set of Leaf nodes via a series of
intermediate Replication nodes. The tree consists of:
* A Replication segment at the Root node.
* Zero or more Replication segments at intermediate Replication
nodes.
* Replication segments at the Leaf nodes.
4.1. Replication Segments at Leaf Nodes
A specific service is identified by a service context in a packet. A
PTI is usually associated with one and only one multipoint service.
On a Leaf node of such a multipoint service, the transport
identifier, which is the Tree-SID or Replication-SID of the
Replication segment at a Leaf node, is also associated with the
service context because it is not always feasible to separate the
transport and service context with efficient replication in core
since a) multipoint services may have differing sets of endpoints and
b) downstream allocation of a service context cannot be encoded in
packets replicated in the core.
A PTI can be associated with one or more multipoint services on the
Root and Leaf nodes. In SR-MPLS deployments, if it is known a priori
that multipoint services mapped to an SR-MPLS PTI can be uniquely
identified with their service label, a controller MAY opt to not
instantiate Replication segments at Leaf nodes. In such cases,
Replication nodes upstream of the Leaf nodes can remove the Tree-SID
from the packet before forwarding it. A multipoint service context
allocated from an upstream assigned label or Domain-wide Common Block
(DCB), as specified in [RFC9573], is an example of a globally unique
context that facilitates this optimization.
In SRv6 deployments, Replication segments of a PTI MUST be
instantiated on Leaf nodes of the tree since behavior like
Penultimate Hop Popping (PHP) is not feasible because the Tree-SID is
carried in the IPv6 Destination Address field of the outer IPv6
header. If two or more multipoint services are mapped to one SRv6
PTI, an SRV6 SID representing the service context is assigned by the
Root node or assigned from the DCB. This SRv6 SID MUST be encoded as
the last segment in the Segment List of the Segment Routing Header
[RFC8754] by the Root node to derive the packet processing context
(PPC) for the service, as described in Section 2.2 of [RFC9524], at a
Leaf node.
4.2. Shared Replication Segments
A Replication segment MAY be shared across different PTIs. One
simple use of a shared Replication segment is for local protection on
a Replication node. A shared Replication segment can protect Assume a Replication node, say node X, has
multiple PTIs. Assume the Replications segments of different these PTIs against an adjacency or path
failure
replicate to the a downstream node, say node Y, amongst other downstream
nodes. This node Y is a common downstream node of these Replication segments.
segments at node X. A Replication segment is established to protect
the adjacency or path between node X and node Y; this Replication
segment can be shared across all the Replication segments of the PTIs
replicating from node X to node Y.
A shared Replication segment MUST be identified using a Root set to
zero (0.0.0.0 for IPv4 and :: for IPv6), an Instance-ID set to zero,
and a Tree-ID that is unique within the context of the node where the
Replication segment is instantiated. The Root is zero because a
shared Replication segment is not associated with a particular SR
P2MP Policy or a PTI. Note that the shared Replication segment
identifier Replication-SID conforms
with the updated Replication-ID definition in Section 2.3.
It is possible for different PTIs to share a P2MP tree at a
Replication node. This allows a common sub-tree to be shared across
PTIs whose tree topologies are identical in some portion of an SR
domain. The procedures to share a P2MP tree across PTIs are outside
the scope of this document.
4.3. Packet Forwarding in a P2MP Tree Instance
When a packet is steered into a PTI, the Replication segment at the
Root node performs packet replication and forwards copies to
downstream nodes.
* Each replicated packet carries the Replication-SID of the
Replication segment at the downstream node.
* A downstream node can be either:
- A Leaf node, in which case the replication process terminates,
or
- An intermediate Replication node, which further replicates the
packet through its associated Replication segments until it
reaches all Leaf nodes.
A Replication node and a downstream node can be non-adjacent. In
this case, the replicated packet has to traverse a path to reach the
downstream node. For SR-MPLS, this is achieved by inserting one or
more SIDs before the downstream Replication-SID. For SRv6, the LOC
[RFC8986] of the downstream Replication-SID can guide the packet to
the downstream node or an optional segment list may be used to steer
the replicated packet on a specific path to the downstream node. For
details of SRv6 replication to a non-adjacent downstream node and
IPv6 Hop Limit considerations, refer to Section 2.2 of [RFC9524].
5. Using a Controller to Build a P2MP Tree
A controller is instantiated or provisioned with the SR P2MP Policy
and its candidate paths CPs to compute and instantiate PTIs in an SR domain. The
procedures for provisioning or instantiation of these constructs on a
controller are outside the scope of this document.
5.1. SR P2MP Policy on a Controller
An SR P2MP Policy is provisioned on a controller by an entity that
can be an operator, a network node, or a machine by specifying the
addresses of the Root, the set of Leaf nodes, and the candidate
paths. CPs. In this
case, the policy and its CPs are instantiated on the Root node using
a signaling protocol. An SR P2MP Policy, its Leaf nodes, and the CPs
may also be provisioned on the Root node and then instantiated on the
controller using a signaling protocol. The procedures and mechanisms
for provisioning and instantiation of an SR P2MP Policy and its CPS
on a controller or a Root node are outside the scope of this
document.
The possible set of constraints and optimization objective of a CP
are described in Section 3 of [SR-POLICY]. Other constraints and
optimization objectives MAY be used for P2MP tree computation.
5.2. Controller Functions
A controller performs the following functions in general:
* Topology Discovery: A controller discovers network topology across
Interior Gateway Protocol (IGP) areas, levels, or Autonomous
Systems (ASes).
* Capability Exchange: A controller discovers a node's capability to
participate in an SR P2MP Policy as well as advertise its
capability to support the SR P2MP. P2MP Policy.
5.3. P2MP Tree Compute
A controller computes one or more PTIs for CPs of an SR P2MP Policy.
A CP may not have any PTIs if a controller cannot compute a P2MP tree
for it.
A controller MUST compute a P2MP tree such that there are no loops in
the tree at steady state as required by [RFC9524].
A controller SHOULD modify a PTI of a candidate path CP on detecting a change in the
network topology if the change affects the tree instance or when a
better path can be found based on the new network state.
Alternatively, the controller MAY decide to implement a Make-
Before-Break Make-Before-
Break approach to minimize traffic loss. The controller can do this
by creating a new PTI, activating the new instance once it is
instantiated in the network, and then removing the old PTI.
5.4. SID Management
The controller assigns the Replication-SIDs for the Replication
segments of the PTI.
The Replication-SIDs of a PTI of a CP of an SR P2MP Policy can be
either dynamically assigned by the controller or statically assigned
by the entity provisioning the SR P2MP Policy.
For SR-MPLS, a Replication-SID may be assigned from the SR Local
Block (SRLB) or the SR Global Block (SRGB) [RFC8402]. It is
RECOMMENDED to assign a Replication-SID from the SRLB since
Replication segments are local to each node of the PTI. It is NOT
RECOMMENDED to allocate a Replication-SID from the SRGB since this
block is globally significant in the SR domain any it may get
depleted if a significant number of PTIs are instantiated in the SR
domain.
Section 3 recommends that the Tree-SID be used as the Replication-
SIDs for all the Replication segments of a PTI. It may be feasible
to allocate the same Tree-SID value for all the Replication segments
if the blocks used for allocation are not identical on all the nodes
of the PTI or if the particular Tree-SID value in the block is
assigned to some other SID on some node.
A BSID is also assigned for the SR P2MP Policy. The controller MAY
decide to not assign a BSID and allow the Root node of the SR P2MP
Policy to assign the BSID. It is RECOMMENDED to assign the BSID of
an SR P2MP Policy from the SRLB for SR-MPLS.
The controller MAY be provisioned with a reserved block or multiple
reserved blocks for assigning Replication-SIDs and/or the BSIDs for
SR P2MP Policies. A single block maybe be reserved for the whole SR
domain, or dedicated blocks can be reserved for each node or a group
of nodes in the SR domain. These blocks MAY overlap with either the
SRGB, the SRLB, or both. The procedures for provisioning these
reserved blocks and procedures for deconflicting assignments from
these reserved blocks with overlapping SRLB or SRGB blocks are
outside the scope of this document.
A controller may not be aware of all the assignments of SIDs from the
SRGB or the SRLB of the SR domain. If reserved blocks are not used,
the assignment of Replication-SIDs or BSIDs of SR P2MP Policies from
these blocks may conflict with other SIDs.
5.5. Instantiating P2MP Tree Instance on Nodes
After computing P2MP trees, the controller instantiates the
Replication segments that compose the PTIs in the SR domain using
signaling protocols such as the Path Computation Element
Communication Protocol (PCEP) [SR-P2MP-PING], [SR-P2MP-PCEP], BGP [P2MP-BGP], or
other mechanisms such as NETCONF/YANG [SR-P2MP-YANG], etc. The
procedures for the instantiation of the Replication segments in an SR
domain are outside the scope of this document.
A node SHOULD report a successful instantiation of a Replication
segment. The exact procedure for reporting this is outside the scope
of this document.
The instantiation of a Replication segment on a node may fail, e.g.,
when the Replication-SID conflicts with another SID on the node. The
node SHOULD report this, preferably with a reason for the failure,
using a signaling protocol. The exact procedure for reporting this
failure is outside the scope of this document.
If the instantiation of a Replication segment on a node fails, the
controller SHOULD attempt to re-instantiate the Replication segment.
There SHOULD be an upper bound on the number of attempts. If the
instantiation of a Replication segment ultimately fails after the
allowed number of attempts, the controller SHOULD generate an alert
via mechanisms like syslog. These alerts SHOULD be rate-limited to
protect the logging facility in case Replication segment
instantiation fails on multiple nodes. The controller MAY decide to
tear down the PTI if the instantiations of some of the Replication
segments of the instance fail. The controller is RECOMMENDED to tear
down the PTI if the instantiation of the Replication segment on the
Root node fails. The controller can employ different strategies to
retry instantiating a PTI after a failure. These are out of scope of
this document.
A PTI should be instantiated within a reasonable time, especially if
it is the active PTI of an SR P2MP Policy. One approach is the
controller instantiates the Replication segments in a batch. For
example, the controller instantiates the Replication segments of the
Leaf nodes and the intermediate Replication nodes first. If all of
these Replication segments are successfully instantiated, the
controller then proceeds to instantiate the Replication segment at
the Root node. If the Replication segment instantiation at the Root
node succeeds, the controller can immediately activate the instance
if it needs to carry traffic of the SR P2MP Policy. A controller can
adopt a similar approach when instantiating the new PTI for the Make-
Before-Break procedure.
5.6. Protection
5.6.1. Local Protection
A network link, node, or replication branch on a PTI can be protected
using SR Policies [RFC9256]. The backup SR Policies are associated
with replication branches of a Replication segment and are programmed
in the data plane in order to minimize traffic loss when the
protected link/node fails. The segment list of the backup SR Policy
is imposed on the downstream Replication-SID of a replication branch
to steer the traffic on the backup path.
It is also possible to use a node local Loop-Free Alternate [RFC5286]
or Topology Independent Loop-Free Alternate (TI-LFA) [RFC9855]
protection and a Micro-Loop [RFC5715] or SR Micro-Loop [SR-LOOP]
prevention mechanism to protect the links/nodes of a PTI.
5.6.2. Path Protection
A controller can create a disjoint backup tree instance for providing
end-to-end tree protection if the topology permits. This can be
achieved by having a backup CP with constraints and/or optimization
objectives that ensure its PTIs are disjoint from the PTIs of the
primary/active CP.
6. IANA Considerations
This document has no IANA actions.
7. Security Considerations
This document describes how a PTI can be created in an SR domain by
stitching Replication segments together. Some security
considerations for Replication segments outlined in [RFC9524] are
also applicable to this document. Following is a brief reminder of
the same.
those security considerations.
An SR domain needs protection from outside attackers as described in
[RFC8402], [RFC8754], and [RFC8986].
Failure to protect the SR MPLS SR-MPLS domain by correctly provisioning MPLS
support per interface permits attackers from outside the domain to
send packets to receivers of the multipoint services that use the SR
P2MP Policies provisioned within the domain.
Failure to protect the SRv6 domain with inbound Infrastructure Access
Control Lists (IACLs) on external interfaces, combined with failure
to implement the method described in RFC 2827 [BCP38] or apply IACLs
on nodes provisioning SIDs, permits attackers from outside the SR
domain to send packets to the receivers of multipoint services that
use the SR P2MP Policies provisioned within the domain.
Incorrect provisioning of Replication segments by a controller that
computes SR PTI can result in a chain of Replication segments forming
a loop. In this case, replicated packets can create a storm until
MPLS TTL (for SR-MPLS) or IPv6 Hop Limit (for SRv6) decrements to
zero.
The control plane protocols (like PCEP, BGP, etc.) used to
instantiate Replication segments of SR PTI can leverage their own
security mechanisms such as encryption, authentication filtering,
etc.
For SRv6, [RFC9524] describes an exception for the ICMPv6 Parameter
Problem
message, code 2 ICMPv6 Error messages. message with Code 2. If an attacker is able to inject a
packet into a multipoint service with the source address of a node
and with an extension header using an unknown option type marked as
mandatory, then a large number of ICMPv6 Parameter Problem messages
can cause a denial-of-service attack on the source node.
8. References
8.1. 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>.
[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>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC9256] Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov,
A., and P. Mattes, "Segment Routing Policy Architecture",
RFC 9256, DOI 10.17487/RFC9256, July 2022,
<https://www.rfc-editor.org/info/rfc9256>.
[RFC9524] Voyer, D., Ed., Filsfils, C., Parekh, R., Bidgoli, H., and
Z. Zhang, "Segment Routing Replication for Multipoint
Service Delivery", RFC 9524, DOI 10.17487/RFC9524,
February 2024, <https://www.rfc-editor.org/info/rfc9524>.
8.2. Informative References
[BCP38] Best Current Practice 38,
<https://www.rfc-editor.org/info/bcp38>.
At the time of writing, this BCP comprises the following:
Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
May 2000, <https://www.rfc-editor.org/info/rfc2827>.
[P2MP-BGP] Bidgoli, H., Voyer, D., Stone, A., Parekh, R., Krier, S.,
and S. Agrawal, "Advertising p2mp policies in BGP", Work
in Progress, Internet-Draft, draft-ietf-idr-sr-p2mp-
policy-00, 27 May 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-sr-
p2mp-policy-00>.
[RFC4655] Farrel, A., Vasseur, J.-P., 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>.
[RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for
IP Fast Reroute: Loop-Free Alternates", RFC 5286,
DOI 10.17487/RFC5286, September 2008,
<https://www.rfc-editor.org/info/rfc5286>.
[RFC5715] Shand, M. and S. Bryant, "A Framework for Loop-Free
Convergence", RFC 5715, DOI 10.17487/RFC5715, January
2010, <https://www.rfc-editor.org/info/rfc5715>.
[RFC8660] Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing with the MPLS Data Plane", RFC 8660,
DOI 10.17487/RFC8660, December 2019,
<https://www.rfc-editor.org/info/rfc8660>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/info/rfc8754>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>.
[RFC9573] Zhang, Z., Rosen, E., Lin, W., Li, Z., and IJ. Wijnands,
"MVPN/EVPN Tunnel Aggregation with Common Labels",
RFC 9573, DOI 10.17487/RFC9573, May 2024,
<https://www.rfc-editor.org/info/rfc9573>.
[RFC9855] Bashandy, A., Litkowski, S., Filsfils, C., Francois, P.,
Decraene, B., and D. Voyer, "Topology Independent Fast
Reroute Using Segment Routing", RFC 9855,
DOI 10.17487/RFC9855, October 2025,
<https://www.rfc-editor.org/info/rfc9855>.
[SR-LOOP] Bashandy, A., Filsfils, C., Litkowski, S., Decraene, B.,
Francois, P., and P. Psenak, "Loop avoidance using Segment
Routing", Work in Progress, Internet-Draft, draft-
bashandy-rtgwg-segment-routing-uloop-17, 29 June 2024,
<https://datatracker.ietf.org/doc/html/draft-bashandy-
rtgwg-segment-routing-uloop-17>.
[SR-P2MP-PING]
[SR-P2MP-PCEP]
Bidgoli, H., Voyer, D., Budhiraja, A., Parekh, R., and S.
Sivabalan, "PCEP extensions for SR P2MP Policy", Work in
Progress, Internet-Draft, draft-ietf-pce-sr-p2mp-policy-
14, 23 February 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-pce-sr-
p2mp-policy-14>.
[SR-P2MP-YANG]
Bidgoli, H., Voyer, D., Parekh, R., Saad, T., and T.
Kundu, "YANG Data Model for p2mp sr policy", Work in
Progress, Internet-Draft, draft-hb-spring-sr-p2mp-policy-
yang-02, 30 October 2020,
<https://datatracker.ietf.org/doc/html/draft-hb-spring-sr-
p2mp-policy-yang-02>.
[SR-POLICY]
Filsfils, C., Talaulikar, K., Król, P. G., Horneffer, M.,
and P. Mattes, "SR Policy Implementation and Deployment
Considerations", Work in Progress, Internet-Draft, draft-
filsfils-spring-sr-policy-considerations-09, 24 April
2022, <https://datatracker.ietf.org/doc/html/draft-
filsfils-spring-sr-policy-considerations-09>.
Appendix A. Illustration of the SR P2MP Policy and P2MP Tree
Consider the following topology:
R3------R6
Controller--/ \
R1----R2----R5-----R7
\ /
+--R4---+
Figure 1: SR Topology
In these examples, the Node-SID of a node Rn is N-SIDn and the
Adjacency-SID from node Rm to node Rn is A-SIDmn. The interface
between Rm and Rn is Lmn.
For SRv6, the reader is expected to be familiar with SRv6 Network
Programming [RFC8986] to follow the examples.
* 2001:db8::/32 is an IPv6 block allocated by a Regional Internet
Registry (RIR) to the operator.
* 2001:db8:0::/48 is dedicated to the internal address space.
* 2001:db8:cccc::/48 is dedicated to the internal SRv6 SID space.
* We assume a location is expressed in 64 bits and a function is
expressed in 16 bits.
* Node k has a classic IPv6 loopback address 2001:db8::k/128, which
is advertised in the IGP.
* Node k has 2001:db8:cccc:k::/64 for its local SID space. Its SIDs
will be explicitly assigned from that block.
* Node k advertises 2001:db8:cccc:k::/64 in its IGP.
* Function :1:: (function 1, for short) represents the End function
with Penultimate Segment Pop (PSP) support.
* Function :Cn:: (function Cn, for short) represents the End.X
function to node n.
* Function :C1n: (function C1n for short) represents the End.X
function to node n with Ultimate Segment Decapsulation (USD).
Each node k has:
* An explicit SID instantiation 2001:db8:cccc:k:1::/128 bound to an
End function with additional support for PSP
* An explicit SID instantiation 2001:db8:cccc:k:Cj::/128 bound to an
End.X function to neighbor J with additional support for PSP
* An explicit SID instantiation 2001:db8:cccc:k:C1j::/128 bound to
an End.X function to neighbor J with additional support for USD
Assume a controller is provisioned with the following SR P2MP Policy
at Root R1 with Tree-ID T-ID:
SR P2MP Policy <R1,T-ID>:
Leaf nodes: {R2, R6, R7}
candidate-path 1:
Optimize: IGP metric
Tree-SID: T-SID1
The controller is responsible for computing a PTI of the candidate
path. CP. In this
example, we assume one active PTI with Instance-ID I-ID1. Assume the
controller instantiates PTIs by signaling Replication segments, i.e.,
the Replication-ID of these Replication segments is <Root, Tree-ID,
Instance-ID>. All Replication segments use the Tree-SID T-SID1 as
the Replication-SID. For SRv6, assume the Replication-SID at node k,
bound to an End.Replicate function, is 2001:db8:cccc:k:fa::/128.
A.1. P2MP Tree with Non-Adjacent Replication Segments
Assume the controller computes a PTI with Root node R1, Intermediate
and Leaf node R2, and Leaf nodes R6 and R7. The controller
instantiates the instance by stitching Replication segments at R1,
R2, R6, and R7. The Replication segment at R1 replicates to R2. The
Replication segment at R2 replicates to R6 and R7. Note that nodes
R3, R4, and R5 do not have any Replication segment state for the
tree.
A.1.1. SR-MPLS
The Replication segment state at nodes R1, R2, R6, and R7 is shown
below.
Replication segment at R1:
Replication segment <R1,T-ID,I-ID1,R1>:
Replication-SID: T-SID1
Replication State:
R2: <T-SID1->L12>
Replication to R2 steers a packet directly to the node on interface
L12.
Replication segment at R2:
Replication segment <R1,T-ID,I-ID1,R2>:
Replication-SID: T-SID1
Replication State:
R2: <Leaf>
R6: <N-SID6, T-SID1>
R7: <N-SID7, T-SID1>
R2 is a Bud node. It performs the role of a Leaf as well as a
transit node replicating to R6 and R7. Replication to R6, using
N-SID6, steers a packet via IGP shortest path to that node.
Replication to R7, using N-SID7, steers a packet via IGP shortest
path to R7 via either R5 or R4 based on ECMP hashing.
Replication segment at R6:
Replication segment <R1,T-ID,I-ID1,R6>:
Replication-SID: T-SID1
Replication State:
R6: <Leaf>
Replication segment at R7:
Replication segment <R1,T-ID,I-ID1,R7>:
Replication-SID: T-SID1
Replication State:
R7: <Leaf>
When a packet is steered into the active instance candidate path CP 1 of the SR P2MP
Policy at R1:
* Since R1 is directly connected to R2, R1 performs the PUSH
operation with just the <T-SID1> label for the replicated copy and
sends it to R2 on interface L12.
* R2, as a Leaf, performs the NEXT operation, pops the T-SID1 label,
and delivers the payload. For replication to R6, R2 performs a
PUSH operation of N-SID6 to send the <N-SID6,T-SID1> label stack
to R3. R3 is the penultimate hop for N-SID6; it performs
penultimate hop popping, PHP,
which corresponds to the NEXT operation, and the packet is then
sent to R6 with <T-SID1> in the label stack. For replication to
R7, R2 performs a PUSH operation of N-SID7 to send the
<N-SID7,T-SID1> label stack to R4, which is one of the IGP ECMP nexthops
next hops (R5 is other) towards R7. R4 is the penultimate hop for
N-SID7; it performs penultimate hop popping, PHP, which corresponds to the NEXT operation,
and the packet is then sent to R7 with <T-SID1> in the label
stack.
* R6, as a Leaf, performs the NEXT operation, pops the T-SID1 label,
and delivers the payload.
* R7, as a Leaf, performs the NEXT operation, pops the T-SID1 label,
and delivers the payload.
A.1.2. SRv6
For SRv6, the replicated packet from R2 to R7 has to traverse R4
using an SR Policy, Policy27. The policy has one SID in the segment
list: End.X function with USD of R4 to R7. The Replication segment
state at nodes R1, R2, R6, and R7 is shown below.
Policy27: <2001:db8:cccc:4:c17::>
Replication segment at R1:
Replication segment <R1,T-ID,I-ID1,R1>:
Replication-SID: 2001:db8:cccc:1:fa::
Replication State:
R2: <2001:db8:cccc:2:fa::->L12>
Replication to R2 steers a packet directly to the node on interface
L12.
Replication segment at R2:
Replication segment <R1,T-ID,I-ID1,R2>:
Replication-SID: 2001:db8:cccc:2:fa::
Replication State:
R2: <Leaf>
R6: <2001:db8:cccc:6:fa::>
R7: <2001:db8:cccc:7:fa:: -> Policy27>
R2 is a Bud node. It performs the role of a Leaf as well as a
transit node replicating to R6 and R7. Replication to R6 steers a
packet via IGP shortest path to that node. Replication to R7, via an
SR Policy, first encapsulates the packet using H.Encaps and then
steers the outer packet to R4. End.X USD on R4 decapsulates the
outer header and sends the original inner packet to R7.
Replication segment at R6:
Replication segment <R1,T-ID,I-ID1,R6>:
Replication-SID: 2001:db8:cccc:6:fa::
Replication State:
R6: <Leaf>
Replication segment at R7:
Replication segment <R1,T-ID,I-ID1,R7>:
Replication-SID: 2001:db8:cccc:7:fa::
Replication State:
R7: <Leaf>
When a packet (A,B2) is steered into the active instance of candidate
path CP 1 of
the SR P2MP Policy at R1 using H.Encaps.Replicate behavior:
* Since R1 is directly connected to R2, R1 sends the replicated copy
(2001:db8::1, 2001:db8:cccc:2:fa::) (A,B2) to R2 on interface L12.
* R2, as a Leaf, removes the outer IPv6 header and delivers the
payload. R2, as a Bud node, also replicates the packet.
* - For replication to R6, R2 sends (2001:db8::1,
2001:db8:cccc:6:fa::) (A,B2) to R3. R3 forwards the packet
using the 2001:db8:cccc:6::/64 packet to R6.
- For replication to R7 using Policy27, R2 encapsulates and sends
(2001:db8::2, 2001:db8:cccc:4:C17::) (2001:db8::1,
2001:db8:cccc:7:fa::) (A,B2) to R4. R4 performs End.X USD
behavior, decapsulates the outer IPv6 header, and sends
(2001:db8::1, 2001:db8:cccc:7:fa::) (A,B2) to R7.
* R6, as a Leaf, removes the outer IPv6 header and delivers the
payload.
* R7, as a Leaf, removes the outer IPv6 header and delivers the
payload.
A.2. P2MP Tree with Adjacent Replication Segments
Assume the controller computes a PTI with Root node R1, Intermediate
and Leaf node R2, Intermediate nodes R3 and R5, and Leaf nodes R6 and
R7. The controller instantiates the PTI by stitching Replication
segments at R1, R2, R3, R5, R6, and R7. The Replication segment at
R1 replicates to R2. The Replication segment at R2 replicates to R3
and R5. The Replication segment at R3 replicates to R6. The
Replication segment at R5 replicates to R7. Note that node R4 does
not have any Replication segment state for the tree.
A.2.1. SR-MPLS
The Replication segment state at nodes R1, R2, R3, R5, R6, and R7 is
shown below.
Replication segment at R1:
Replication segment <R1,T-ID,I-ID1,R1>:
Replication-SID: T-SID1
Replication State:
R2: <T-SID1->L12>
Replication to R2 steers a packet directly to the node on interface
L12.
Replication segment at R2:
Replication segment <R1,T-ID,I-ID1,R2>:
Replication-SID: T-SID1
Replication State:
R2: <Leaf>
R3: <T-SID1->L23>
R5: <T-SID1->L25>
R2 is a Bud node. It performs the role of a Leaf as well as a
transit node replicating to R3 and R5. Replication to R3 steers a
packet directly to the node on L23. Replication to R5 steers a
packet directly to the node on L25.
Replication segment at R3:
Replication segment <R1,T-ID,I-ID1,R3>:
Replication-SID: T-SID1
Replication State:
R6: <T-SID1->L36>
Replication to R6 steers a packet directly to the node on L36.
Replication segment at R5:
Replication segment <R1,T-ID,I-ID1,R5>:
Replication-SID: T-SID1
Replication State:
R7: <T-SID1->L57>
Replication to R7 steers a packet directly to the node on L57.
Replication segment at R6:
Replication segment <R1,T-ID,I-ID1,R6>:
Replication-SID: T-SID1
Replication State:
R6: <Leaf>
Replication segment at R7:
Replication segment <R1,T-ID,I-ID1,R7>:
Replication-SID: T-SID1
Replication State:
R7: <Leaf>
When a packet is steered into the SR P2MP Policy at R1:
* Since R1 is directly connected to R2, R1 performs the PUSH
operation with just the <T-SID1> label for the replicated copy and
sends it to R2 on interface L12.
* R2, as a Leaf, performs the NEXT operation, pops the T-SID1 label,
and delivers the payload. It also performs the PUSH operation on
T-SID1 for replication to R3 and R5. For replication to R6, R2
sends the <T-SID1> label stack to R3 on interface L23. For
replication to R5, R2 sends the <T-SID1> label stack to R5 on
interface L25.
* R3 performs the NEXT operation on T-SID1, performs a PUSH
operation for replication to R6, and sends the <T-SID1> label
stack to R6 on interface L36.
* R5 performs the NEXT operation on T-SID1, performs a PUSH
operation for replication to R7, and sends the <T-SID1> label
stack to R7 on interface L57.
* R6, as a Leaf, performs the NEXT operation, pops the T-SID1 label,
and delivers the payload.
* R7, as a Leaf, performs the NEXT operation, pops the T-SID1 label,
and delivers the payload.
A.2.2. SRv6
The Replication segment state at nodes R1, R2, R3, R5, R6, and R7 is
shown below.
Replication segment at R1:
Replication segment <R1,T-ID,I-ID1,R1>:
Replication-SID: 2001:db8:cccc:1:fa::
Replication State:
R2: <2001:db8:cccc:2:fa::->L12>
Replication to R2 steers a packet directly to the node on interface
L12.
Replication segment at R2:
Replication segment <R1,T-ID,I-ID1,R2>:
Replication-SID: 2001:db8:cccc:2:fa::
Replication State:
R2: <Leaf>
R3: <2001:db8:cccc:3:fa::->L23>
R5: <2001:db8:cccc:5:fa::->L25>
R2 is a Bud node. It performs the role of a Leaf as well as a
transit node replicating to R3 and R5. Replication to R3 steers a
packet directly to the node on L23. Replication to R5 steers a
packet directly to the node on L25.
Replication segment at R3:
Replication segment <R1,T-ID,I-ID1,R3>:
Replication-SID: 2001:db8:cccc:3:fa::
Replication State:
R6: <2001:db8:cccc:6:fa::->L36>
Replication to R6 steers a packet directly to the node on L36.
Replication segment at R5:
Replication segment <R1,T-ID,I-ID1,R5>:
Replication-SID: 2001:db8:cccc:5:fa::
Replication State:
R7: <2001:db8:cccc:7:fa::->L57>
Replication to R7 steers a packet directly to the node on L57.
Replication segment at R6:
Replication segment <R1,T-ID,I-ID1,R6>:
Replication-SID: 2001:db8:cccc:6:fa::
Replication State:
R6: <Leaf>
Replication segment at R7:
Replication segment <R1,T-ID,I-ID1,R7>:
Replication-SID: 2001:db8:cccc:7:fa::
Replication State:
R7: <Leaf>
When a packet (A,B2) is steered into the active instance of candidate
path CP 1 of
the SR P2MP Policy at R1 using the H.Encaps.Replicate behavior:
* Since R1 is directly connected to R2, R1 sends the replicated copy
(2001:db8::1, 2001:db8:cccc:2:fa::) (A,B2) to R2 on interface L12.
* R2, as a Leaf, removes the outer IPv6 header and delivers the
payload. R2, as a Bud node, also replicates the packet. For
replication to R3, R2 sends (2001:db8::1, 2001:db8:cccc:3:fa::)
(A,B2) to R3 on interface L23. For replication to R5, R2 sends
(2001:db8::1, 2001:db8:cccc:5:fa::) (A,B2) to R5 on interface L25.
* R3 replicates and sends (2001:db8::1, 2001:db8:cccc:6:fa::) (A,B2)
to R6 on interface L36.
* R5 replicates and sends (2001:db8::1, 2001:db8:cccc:7:fa::) (A,B2)
to R7 on interface L57.
* R6, as a Leaf, removes the outer IPv6 header and delivers the
payload.
* R7, as a Leaf, removes the outer IPv6 header and delivers the
payload.
Acknowledgements
The authors would like to acknowledge Siva Sivabalan, Mike Koldychev,
and Vishnu Pavan Beeram for their valuable input.
Contributors
Clayton Hassen
Bell Canada
Vancouver
Canada
Email: clayton.hassen@bell.ca
Kurtis Gillis
Bell Canada
Halifax
Canada
Email: kurtis.gillis@bell.ca
Arvind Venkateswaran
Cisco Systems, Inc.
San Jose,
United States of America
Email: arvvenka@cisco.com
Zafar Ali
Cisco Systems, Inc.
United States of America
Email: zali@cisco.com
Swadesh Agrawal
Cisco Systems, Inc.
San Jose,
United States of America
Email: swaagraw@cisco.com
Jayant Kotalwar
Nokia
Mountain View,
United States of America
Email: jayant.kotalwar@nokia.com
Tanmoy Kundu
Nokia
Mountain View,
United States of America
Email: tanmoy.kundu@nokia.com
Andrew Stone
Nokia
Ottawa
Canada
Email: andrew.stone@nokia.com
Tarek Saad
Juniper Networks
Canada
Email: tsaad@juniper.net
Kamran Raza
Cisco Systems, Inc.
Canada
Email: skraza@cisco.com
Anuj Budhiraja
Cisco Systems, Inc.
United States of America
Email: abudhira@cisco.com
Mankamana Mishra
Cisco Systems, Inc.
United States of America
Email: mankamis@cisco.com
Authors' Addresses
Rishabh Parekh (editor)
Arrcus
San Jose,
United States of America
Email: rishabh@arrcus.com
Daniel Voyer (editor)
Cisco Systems, Inc.
Montreal
Canada
Email: davoyer@cisco.com
Clarence Filsfils
Cisco Systems, Inc.
Brussels
Belgium
Email: cfilsfil@cisco.com
Hooman Bidgoli
Nokia
Ottawa
Canada
Email: hooman.bidgoli@nokia.com
Zhaohui Zhang
Juniper Networks
Email: zzhang@juniper.net