Internet Engineering Task Force (IETF) F. Zhang, Ed.
Request for Comments: 8001 Huawei
Category: Standards Track O. Gonzalez de Dios, Ed.
ISSN: 2070-1721 Telefonica Global CTO
C. Margaria
Juniper
M. Hartley
Z. Ali
Cisco
January 2017
RSVP-TE Extensions for Collecting
Shared Risk Link Group (SRLG) Information
Abstract
This document provides extensions for Resource Reservation Protocol -
Traffic Engineering (RSVP-TE), including GMPLS, to support automatic
collection of Shared Risk Link Group (SRLG) information for the TE
link formed by a Label Switched Path (LSP).
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
http://www.rfc-editor.org/info/rfc8001.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Applicability Example: Dual-Homing . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 5
3. RSVP-TE Requirements . . . . . . . . . . . . . . . . . . . . . 5
3.1. SRLG Collection Indication . . . . . . . . . . . . . . . . 5
3.2. SRLG Collection . . . . . . . . . . . . . . . . . . . . . 6
3.3. SRLG Update . . . . . . . . . . . . . . . . . . . . . . . 6
3.4. SRLG ID Definition . . . . . . . . . . . . . . . . . . . . 6
4. Encodings . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. SRLG Collection Flag . . . . . . . . . . . . . . . . . . . 6
4.2. RRO SRLG Subobject . . . . . . . . . . . . . . . . . . . 7
5. Signaling Procedures . . . . . . . . . . . . . . . . . . . . . 8
5.1. SRLG Collection . . . . . . . . . . . . . . . . . . . . . 8
5.2. SRLG Update . . . . . . . . . . . . . . . . . . . . . . . 10
5.3 Domain Boundaries . . . . . . . . . . . . . . . . . . . . . 10
5.4. Compatibility . . . . . . . . . . . . . . . . . . . . . . 11
6. Manageability Considerations . . . . . . . . . . . . . . . . . 11
6.1. Policy Configuration . . . . . . . . . . . . . . . . . . . 11
6.2. Coherent SRLG IDs . . . . . . . . . . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8.1. RSVP Attribute Bit Flags . . . . . . . . . . . . . . . . . 12
8.2. ROUTE_RECORD Object . . . . . . . . . . . . . . . . . . . 12
8.3. Policy Control Failure Error Subcodes . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
9.1. Normative References . . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . . 14
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . 15
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
It is important to understand which Traffic Engineering (TE) links in
a given network might be at risk from the same failures. In this
sense, a set of links can constitute a Shared Risk Link Group (SRLG)
if they share a resource whose failure can affect all links in the
set [RFC4202].
On the other hand, as described in [RFC4206] and [RFC6107], a
Hierarchical LSP (H-LSP) or stitched LSP (S-LSP) can be used for
carrying one or more other LSPs. Both the H-LSP and S-LSP can be
formed as a TE link. In such cases, it is important to know the SRLG
information of the LSPs that will be used to carry further LSPs.
This document provides a signaling mechanism that collects the SRLGs
that are used by an LSP and can then be advertised as properties of
the TE link formed by that LSP.
1.1. Applicability Example: Dual-Homing
An interesting use case for the SRLG collection procedures defined in
this document is achieving LSP diversity in a dual-homing scenario.
The use case is illustrated in Figure 1, when the overlay model is
applied as defined in [RFC4208]. In this example, the exchange of
routing information over the User-Network Interface (UNI) is
prohibited by operator policy.
+---+ +---+
| P |....| P |
+---+ +---+
/ \
+-----+ +-----+
+---+ | PE1 | | PE3 | +---+
|CE1|----| | | |----|CE2|
+---+\ +-----+ +-----+ /+---+
\ | | /
\ +-----+ +-----+ /
\| PE2 | | PE4 |/
| | | |
+-----+ +-----+
\ /
+---+ +---+
| P |....| P |
+---+ +---+
Figure 1: Dual-Homing Configuration
Single-homed customer edge (CE) devices are connected to a single
provider edge (PE) device via a single UNI link (which could be a
bundle of parallel links, typically using the same fiber cable).
This single UNI link can constitute a single point of failure. Such
a single point of failure can be avoided if the CE device is
connected to two PE devices via two UNI interfaces for CE1 and CE2,
respectively, as depicted in Figure 1.
For the dual-homing case, it is possible to establish two connections
(LSPs) from the source CE device to the same destination CE device
where one connection is using one UNI link to PE1, for example, and
the other connection is using the UNI link to PE2. In order to avoid
single points of failure within the provider network, it is necessary
to also ensure path (LSP) diversity within the provider network to
achieve end-to-end diversity for the two LSPs between the two CE
devices CE1 and CE2. This use case describes how it is possible to
achieve path diversity within the provider network based on collected
SRLG information. As the two connections (LSPs) enter the provider
network at different PE devices, the PE device that receives the
connection request for the second connection needs to know the
additional path computation constraints such that the path of the
second LSP is disjoint with respect to the already established first
connection.
As SRLG information is normally not shared between the provider
network and the client network, i.e., between PE and CE devices, the
challenge is how to solve the diversity problem when a CE is dual-
homed. The RSVP extensions for collecting SRLG information defined
in this document make it possible to retrieve SRLG information for an
LSP and hence solve the dual-homing LSP diversity problem. For
example, CE1 in Figure 1 may have requested an LSP1 to CE2 via PE1
that is routed via PE3 to CE2. CE1 can then subsequently request an
LSP2 to CE2 via PE2 with the constraint that it needs to be maximally
SRLG disjoint with respect to LSP1. PE2, however, does not have any
SRLG information associated with LSP1, and this is needed as input
for its constraint-based path computation function. If CE1 is
capable of retrieving the SRLG information associated with LSP1 from
PE1, it can pass this discovered information to PE2 as part of the
LSP2 setup request (RSVP PATH message) in an EXCLUDE_ROUTE Object
(XRO) or Explicit Exclusion Route Subobject (EXRS) as described in
[RFC4874], and PE2 can now calculate a path for LSP2 that is SRLG
disjoint with respect to LSP1. The SRLG information associated with
LSP1 can be retrieved when LSP1 is established or at any time before
LSP2 is set up.
When CE1 sends the setup request for LSP2 to PE2, it can also request
the collection of SRLG information for LSP2 and send that information
to PE1 by re-signaling LSP1 with SRLG-exclusion based on LSP2's
discovered SRLGs. This will ensure that the two paths for the two
LSPs remain mutually diverse; this is important when the provider
network is capable of restoring connections that failed due to a
network failure (fiber cut) in the provider network.
Note that the knowledge of SRLG information even for multiple LSPs
does not allow a CE device to derive the provider network topology
based on the collected SRLG information. It would, however, be
possible for an entity controlling multiple CE devices to derive some
information related to the topology. This document therefore allows
PE devices to control the communication of SRLGs outside the provider
network if desired.
2. 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].
3. RSVP-TE Requirements
The SRLG collection process takes place in three stages:
o The LSP's ingress node requests that SRLG collection take place;
o SRLG data is added to the Path and Resv ROUTE_RECORD Objects
(RROs) by all nodes during signaling;
o Changes to previously signaled SRLG data are made by sending
updated Path and Resv messages as required.
3.1. SRLG Collection Indication
The ingress node of the LSP needs be capable of indicating whether
the SRLG information of the LSP is to be collected during the
signaling procedure of setting up an LSP. There is no need for SRLG
information to be collected without an explicit request by the
ingress node.
It may be preferable for the SRLG collection request to be understood
by all nodes along the LSP's path, or it may be more important for
the LSP to be established successfully even if it traverses nodes
that cannot supply SRLG information or have not implemented the
procedures specified in this document. It is desirable for the
ingress node to make the SRLG collection request in a manner that
best suits its own policy.
3.2. SRLG Collection
If requested, the SRLG information is collected during the setup of
an LSP. SRLG information is added by each hop to the Path RRO during
Path message processing. The same information is also added to the
Resv RRO during Resv processing at each hop.
3.3. SRLG Update
When the SRLG information of an existing LSP for which SRLG
information was collected during signaling changes, the relevant
nodes of the LSP need to be capable of updating the SRLG information
of the LSP. This means that the signaling procedure needs to be
capable of updating the new SRLG information.
3.4. SRLG ID Definition
The identifier of an SRLG (SRLG ID) is defined as a 32-bit quantity
in [RFC4202]. This definition is used in this document.
4. Encodings
4.1. SRLG Collection Flag
In order to indicate to nodes that SRLG collection is desired, this
document defines a new flag in the Attribute Flags TLV (see
[RFC5420]). This document defines a new SRLG Collection Flag in the
Attribute Flags TLV. A node that wishes to indicate that SRLG
collection is desired MUST set this flag in an Attribute Flags TLV in
an LSP_REQUIRED_ATTRIBUTES object (if collection is to be mandatory)
or an LSP_ATTRIBUTES object (if collection is desired but not
mandatory).
o Bit Number (specified in Section 8.1): SRLG Collection Flag
The SRLG Collection Flag is meaningful on a Path message. If the
SRLG Collection Flag is set to 1, it means that the SRLG information
SHOULD be reported to the ingress and egress node along the setup of
the LSP.
The rules for the processing of the Attribute Flags TLV are not
changed.
4.2. RRO SRLG Subobject
This document defines a new RRO subobject (ROUTE_RECORD subobject) to
record the SRLG information of the LSP. Its format is modeled on the
RRO subobjects defined in [RFC3209].
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |D| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRLG ID 1 (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ...... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRLG ID n (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type (8 bits)
The type of the subobject. The value is specified in Section 8.2.
Length (8 bits)
The Length field contains the total length of the subobject in
octets, including the Type and Length fields. The Length depends on
the number of SRLG IDs.
Direction bit (D-bit) (1 bit)
If not set, the SRLGs contained in this subobject apply to the
downstream direction. If set, they apply to the upstream direction.
Reserved (15 bits)
This 15-bit field is reserved. It SHOULD be set to zero on
transmission and MUST be ignored on receipt.
SRLG ID (4 octets)
This field contains one SRLG ID. There is one SRLG ID field per SRLG
collected. There MAY be multiple SRLG ID fields in an SRLG
subobject.
A node MUST NOT push an SRLG subobject in the ROUTE_RECORD without
also pushing either an IPv4 subobject, an IPv6 subobject, an
Unnumbered Interface ID subobject, or a Path Key Subobject (PKS).
As described in [RFC3209], the ROUTE_RECORD object is managed as a
stack. The SRLG subobject MUST be pushed by the node before the node
IP address or link identifier. The SRLG subobject SHOULD be pushed
after the Attribute subobject, if present, and after the LABEL
subobject, if requested. It MUST be pushed within the hop to which
it applies.
[RFC5553] describes mechanisms to carry a PKS in the RRO so as to
facilitate confidentiality in the signaling of inter-domain TE LSPs.
RFC 5553 allows the path segment that needs to be hidden (that is, a
Confidential Path Segment (CPS)) to be replaced in the RRO with a
PKS. If the CPS contains SRLG subobjects, these MAY be retained in
the RRO by adding them again after the PKS in the RRO. The CPS is
defined in [RFC5520].
The rules for the processing of the LSP_REQUIRED_ATTRIBUTES,
LSP_ATTRIBUTES, and ROUTE_RECORD objects are not changed.
5. Signaling Procedures
The ingress node of the LSP MUST be capable of indicating whether the
SRLG information of the LSP is to be collected during the signaling
procedure of setting up an LSP.
5.1. SRLG Collection
Per [RFC3209], an ingress node initiates the recording of the route
information of an LSP by adding an RRO to a Path message. If an
ingress node also desires SRLG recording, it MUST set the SRLG
Collection Flag in the Attribute Flags TLV, which MAY be carried in
either an LSP_REQUIRED_ATTRIBUTES object (when the collection is
mandatory) or an LSP_ATTRIBUTES object (when the collection is
desired, but not mandatory).
A node MUST NOT add SRLG information without an explicit request by
the ingress node in the Path message.
When a node receives a Path message that carries an
LSP_REQUIRED_ATTRIBUTES object with the SRLG Collection Flag set, if
local policy determines that the SRLG information is not to be
provided to the endpoints, it MUST return a PathErr message with
o Error Code 2 (policy) and
o Error subcode "SRLG Recording Rejected" (see Section 8.3 for
value)
to reject the Path message.
When a node receives a Path message that carries an LSP_ATTRIBUTES
object with the SRLG Collection Flag set, if local policy determines
that the SRLG information is not to be provided to the endpoints, the
Path message MUST NOT be rejected due to the SRLG recording
restriction, and the Path message MUST be forwarded without any SRLG
subobject(s) added to the RRO of the corresponding outgoing Path
message.
If local policy permits the recording of the SRLG information, the
processing node SHOULD add local SRLG information, as defined below,
to the RRO of the corresponding outgoing Path message. The
processing node MAY add multiple SRLG subobjects to the RRO if
necessary. It then forwards the Path message to the next node in the
downstream direction. The processing node MUST retain a record of
the SRLG recording request for reference during Resv processing
described below.
If the addition of SRLG information to the RRO would result in the
RRO exceeding its maximum possible size or becoming too large for the
Path message to contain it, the requested SRLGs MUST NOT be added.
If the SRLG collection request was contained in an
LSP_REQUIRED_ATTRIBUTES object, the processing node MUST behave as
specified by [RFC3209] and drop the RRO from the Path message
entirely. If the SRLG collection request was contained in an
LSP_ATTRIBUTES object, the processing node MAY omit some or all of
the requested SRLGs from the RRO; otherwise, it MUST behave as
specified by [RFC3209] and drop the RRO from the Path message
entirely. Subsequent processing of the LSP proceeds as further
specified in [RFC3209].
Following the steps described above, the intermediate nodes of the
LSP can collect the SRLG information in the RRO during the processing
of the Path message hop by hop. When the Path message arrives at the
egress node, the egress node receives SRLG information in the RRO.
Per [RFC3209], when issuing a Resv message for a Path message that
contains an RRO, an egress node initiates the RRO process by adding
an RRO to the outgoing Resv message. The processing for RROs
contained in Resv messages then mirrors that of the Path messages.
When a node receives a Resv message for an LSP for which SRLG
Collection was specified in the corresponding Path message, then when
local policy allows recording SRLG information, the node MUST add
SRLG information to the RRO of the corresponding outgoing Resv
message as specified below. When the Resv message arrives at the
ingress node, the ingress node can extract the SRLG information from
the RRO in the same way as the egress node.
Note that a link's SRLG information for the upstream direction cannot
be assumed to be the same as that for the downstream direction.
o For Path and Resv messages for a unidirectional LSP, a node SHOULD
include SRLG subobjects in the RRO for the downstream data link
only.
o For Path and Resv messages for a bidirectional LSP, a node SHOULD
include SRLG subobjects in the RRO for both the upstream data link
and the downstream data link from the local node. In this case,
the node MUST include the information in the same order for both
Path messages and Resv messages. That is, the SRLG subobject for
the upstream link is added to the RRO before the SRLG subobject
for the downstream link.
If SRLG data is added for both the upstream and downstream links,
the two sets of SRLG data MUST be added in separate SRLG
subobjects. A single SRLG subobject MUST NOT contain a mixture of
upstream and downstream SRLGs. When adding a SRLG subobject to an
RRO, the D-bit MUST be set appropriately to indicate the direction
of the SRLGs. If an SRLG ID applies in both directions, it SHOULD
be added to both the upstream and downstream SRLG subobjects.
Based on the above procedure, the endpoints can get the SRLG
information automatically. Then, for instance, the endpoints can
advertise it as a TE link to the routing instance based on the
procedure described in [RFC6107] and configure the SRLG information
of the Forwarding Adjacency (FA) automatically.
5.2. SRLG Update
When the SRLG information of a link is changed, the endpoints of LSPs
using that link need to be made aware of the changes. When a change
to the set of SRLGs associated with a link occurs, the procedures
defined in Section 4.4.3 of [RFC3209] MUST be used to refresh the
SRLG information for each affected LSP if the local node's policy
dictates that the SRLG change be communicated to other nodes.
5.3 Domain Boundaries
If mandated by local policy as specified by the network operator, a
node MAY remove SRLG information from any RRO in a Path or Resv
message being processed. It MAY add a summary of the removed SRLGs
or map them to other SRLG values. However, this SHOULD NOT be done
unless explicitly mandated by local policy.
5.4. Compatibility
A node that does not recognize the SRLG Collection Flag in the
Attribute Flags TLV is expected to proceed as specified in [RFC5420].
It is expected to pass the TLV on unaltered if it appears in an
LSP_ATTRIBUTES object or to reject the Path message with the
appropriate Error Code and Value if it appears in a
LSP_REQUIRED_ATTRIBUTES object.
A node that does not recognize the SRLG RRO subobject is expected to
behave as specified in [RFC3209]: unrecognized subobjects are to be
ignored and passed on unchanged.
6. Manageability Considerations
6.1. Policy Configuration
In a border node of an inter-domain or inter-layer network, the
following SRLG processing policy MUST be capable of being configured:
o Whether the node is allowed to participate in SRLG collection and
notify changes to collected SRLG information to endpoint nodes as
described in Section 5.2.
o Whether the SRLG IDs of the domain or specific layer network can
be exposed to the nodes outside the domain or layer network, or
whether they SHOULD be summarized, mapped to values that are
comprehensible to nodes outside the domain or layer network, or
removed entirely as described in Section 5.3.
A node using [RFC5553] and PKS MAY apply the same policy.
6.2. Coherent SRLG IDs
In a multi-layer, multi-domain scenario, SRLG IDs can be configured
by different management entities in each layer or domain. In such
scenarios, maintaining a coherent set of SRLG IDs is a key
requirement in order to be able to use the SRLG information properly.
Thus, SRLG IDs SHOULD be unique. Note that current procedures are
targeted towards a scenario where the different layers and domains
belong to the same operator or to several coordinated administrative
groups. Ensuring the aforementioned coherence of SRLG IDs is beyond
the scope of this document.
Further scenarios, where coherence in the SRLG IDs cannot be
guaranteed, are out of the scope of the present document and are left
for further study.
7. Security Considerations
This document builds on the mechanisms defined in [RFC3473], which
also discusses related security measures. In addition, [RFC5920]
provides an overview of security vulnerabilities and protection
mechanisms for the GMPLS control plane. The procedures defined in
this document permit the transfer of SRLG data between layers or
domains during the signaling of LSPs, subject to policy at the layer
or domain boundary. As described in Sections 5.3 and 6.1, local
policy as specified by the network operator will explicitly mandate
the processing of information at domain or layer boundaries.
8. IANA Considerations
8.1. RSVP Attribute Bit Flags
IANA has created a registry and manages the space of the Attribute
bit flags of the Attribute Flags TLV, as described in Section 11.3 of
[RFC5420], in the "Attribute Flags" subregistry of the "Resource
Reservation Protocol-Traffic Engineering (RSVP-TE) Parameters"
registry located at
<http://www.iana.org/assignments/rsvp-te-parameters>.
This document introduces a new Attribute bit flag:
Bit No Name Attribute Attribute RRO ERO Reference
Flags Path Flags Resv
--------- ---------- ---------- ----------- --- --- ---------
12 SRLG Yes No Yes No RFC 8001,
Collection [RFC7570]
Flag
8.2. ROUTE_RECORD Object
IANA manages the "Resource Reservation Protocol (RSVP) Parameters"
registry located at
<http://www.iana.org/assignments/rsvp-parameters>. This document
introduces a new RRO subobject under the "Sub-object type - 21
ROUTE_RECORD - Type 1 Route Record" subregistry:
Value Description Reference
----- ------------------- ---------
34 SRLG subobject RFC 8001
8.3. Policy Control Failure Error Subcodes
IANA manages the assignments in the "Error Codes and Globally-Defined
Error Value Sub-Codes" section of the "Resource Reservation Protocol
(RSVP) Parameters" registry located at
<http://www.iana.org/assignments/rsvp-parameters>.
This document introduces a new value under "Sub-Codes - 2 Policy
Control Failure":
Value Description Reference
----- ----------------------- ---------
21 SRLG Recording Rejected RFC 8001
9. References
9.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<http://www.rfc-editor.org/info/rfc3209>.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
DOI 10.17487/RFC3473, January 2003,
<http://www.rfc-editor.org/info/rfc3473>.
[RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing
Extensions in Support of Generalized Multi-Protocol Label
Switching (GMPLS)", RFC 4202, DOI 10.17487/RFC4202,
October 2005, <http://www.rfc-editor.org/info/rfc4202>.
[RFC5420] Farrel, A., Ed., Papadimitriou, D., Vasseur, JP., and A.
Ayyangarps, "Encoding of Attributes for MPLS LSP
Establishment Using Resource Reservation Protocol Traffic
Engineering (RSVP-TE)", RFC 5420, DOI 10.17487/RFC5420,
February 2009, <http://www.rfc-editor.org/info/rfc5420>.
[RFC5520] Bradford, R., Ed., Vasseur, JP., and A. Farrel,
"Preserving Topology Confidentiality in Inter-Domain Path
Computation Using a Path-Key-Based Mechanism", RFC 5520,
DOI 10.17487/RFC5520, April 2009,
<http://www.rfc-editor.org/info/rfc5520>.
[RFC5553] Farrel, A., Ed., Bradford, R., and JP. Vasseur, "Resource
Reservation Protocol (RSVP) Extensions for Path Key
Support", RFC 5553, DOI 10.17487/RFC5553, May 2009,
<http://www.rfc-editor.org/info/rfc5553>.
9.2. Informative References
[RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
Hierarchy with Generalized Multi-Protocol Label Switching
(GMPLS) Traffic Engineering (TE)", RFC 4206,
DOI 10.17487/RFC4206, October 2005,
<http://www.rfc-editor.org/info/rfc4206>.
[RFC4208] Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter,
"Generalized Multiprotocol Label Switching (GMPLS) User-
Network Interface (UNI): Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Support for the Overlay
Model", RFC 4208, DOI 10.17487/RFC4208, October 2005,
<http://www.rfc-editor.org/info/rfc4208>.
[RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes -
Extension to Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE)", RFC 4874, DOI 10.17487/RFC4874,
April 2007, <http://www.rfc-editor.org/info/rfc4874>.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
<http://www.rfc-editor.org/info/rfc5920>.
[RFC6107] Shiomoto, K., Ed., and A. Farrel, Ed., "Procedures for
Dynamically Signaled Hierarchical Label Switched Paths",
RFC 6107, DOI 10.17487/RFC6107, February 2011,
<http://www.rfc-editor.org/info/rfc6107>.
[RFC7570] Margaria, C., Ed., Martinelli, G., Balls, S., and B.
Wright, "Label Switched Path (LSP) Attribute in the
Explicit Route Object (ERO)", RFC 7570,
DOI 10.17487/RFC7570, July 2015,
<http://www.rfc-editor.org/info/rfc7570>.
Acknowledgements
The authors would like to thank Dieter Beller, Vishnu Pavan Beeram,
Lou Berger, Deborah Brungard, Igor Bryskin, Ramon Casellas, Niclas
Comstedt, Alan Davey, Elwyn Davies, Dhruv Dhody, Himanshu Shah, and
Xian Zhang for their useful comments and improvements to this
document.
Contributors
Dan Li
Huawei
F3-5-B RD Center
Bantian, Longgang District, Shenzhen 518129
China
Email: danli@huawei.com
Authors' Addresses
Fatai Zhang (editor)
Huawei
F3-5-B RD Center
Bantian, Longgang District, Shenzhen 518129
China
Email: zhangfatai@huawei.com
Oscar Gonzalez de Dios (editor)
Telefonica Global CTO
Distrito Telefonica, edificio sur, Ronda de la Comunicacion 28045
Madrid 28050
Spain
Phone: +34 913129647
Email: oscar.gonzalezdedios@telefonica.com
Cyril Margaria
Juniper
200 Somerset Corporate Blvd., Suite 4001
Bridgewater, NJ 08807
United States of America
Email: cmargaria@juniper.net
Matt Hartley
Cisco
Email: mhartley@cisco.com
Zafar Ali
Cisco
Email: zali@cisco.com
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