Internet DRAFT - draft-ietf-ccamp-rsvp-te-domain-subobjects
draft-ietf-ccamp-rsvp-te-domain-subobjects
CCAMP Working Group D. Dhody
Internet-Draft U. Palle
Intended status: Experimental V. Kondreddy
Expires: January 2, 2015 Huawei Technologies
R. Casellas
CTTC
July 1, 2014
Domain Subobjects for Resource ReserVation Protocol - Traffic
Engineering (RSVP-TE)
draft-ietf-ccamp-rsvp-te-domain-subobjects-02
Abstract
The Resource ReserVation Protocol - Traffic Engineering (RSVP-TE)
specification and the Generalized Multiprotocol Label Switching
(GMPLS) extensions to RSVP-TE allow abstract nodes and resources to
be explicitly included in a path setup. Further Exclude Routes
extensions to RSVP-TE allow abstract nodes and resources to be
explicitly excluded in a path setup.
This document specifies new subobjects to include or exclude domains
during path setup where domain is a collection of network elements
within a common sphere of address management or path computational
responsibility (such as an Interior Gateway Protocol (IGP) area or an
Autonomous System (AS)). Note that the use of AS as an abstract node
representing domain is already defined in existing RSVP-TE
specefications, albeit with a 2-Byte AS number.
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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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 2, 2015.
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Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Subobjects for Domains . . . . . . . . . . . . . . . . . . . 4
3.1. Domains . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Explicit Route Object (ERO)'s Subobjects . . . . . . . . 5
3.2.1. Autonomous system . . . . . . . . . . . . . . . . . . 6
3.2.2. IGP Area . . . . . . . . . . . . . . . . . . . . . . 6
3.2.3. Mode of Operation . . . . . . . . . . . . . . . . . . 7
3.3. Exclude Route Object (XRO)'s Subobjects . . . . . . . . . 8
3.3.1. Autonomous system . . . . . . . . . . . . . . . . . . 8
3.3.2. IGP Area . . . . . . . . . . . . . . . . . . . . . . 8
3.3.3. Mode of Operation . . . . . . . . . . . . . . . . . . 9
3.4. Explicit Exclusion Route Subobject . . . . . . . . . . . 9
4. Interaction with Path Computation Element (PCE) . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
5.1. New Subobjects . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 10
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 13
A.1. Inter-Area LSP Path Setup . . . . . . . . . . . . . . . . 13
A.2. Inter-AS LSP Path Setup . . . . . . . . . . . . . . . . . 14
A.2.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . 14
A.2.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . 15
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1. Introduction
The RSVP-TE specification [RFC3209] and the GMPLS extensions to RSVP-
TE [RFC3473] allow abstract nodes and resources to be explicitly
included in a path setup using the Explicit Route Object (ERO).
Further Exclude Routes extensions [RFC4874] allow abstract nodes or
resources to be excluded from the whole path using the Exclude Route
object (XRO). To exclude certain abstract nodes or resources between
a specific pair of abstract nodes present in an ERO, a Explicit
Exclusion Route Subobject (EXRS) is used.
[RFC3209] already describes the notion of abstract nodes, where an
abstract node is a group of nodes whose internal topology is opaque
to the ingress node of the Label Switched Path (LSP). It further
defines a subobject for AS, but with a 2-Byte AS number only.
This document extends the notion of abstract nodes by adding new
subobjects for IGP Areas and 4-byte AS numbers (as per [RFC6793]).
These subobjects MAY be included in Explicit Route Object (ERO),
Exclude Route Object (XRO) or Explicit Exclusion Route Subobject
(EXRS).
In case of per-domain path computation [RFC5152], where the full path
of an inter-domain TE LSP cannot be or is not determined at the
ingress node, and signaling message may use domain identifiers. The
use of these new subobjects is illustrated in Appendix A.
Further, the domain identifier may simply act as delimiter to specify
where the domain boundary starts and ends.
This is a companion document to Path Computation Element Protocol
(PCEP) extensions for the domain sequence [PCE-DOMAIN].
1.1. 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].
2. Terminology
The following terminology is used in this document.
AS: Autonomous System.
Domain: As per [RFC4655], any collection of network elements within
a common sphere of address management or path computational
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responsibility. Examples of domains include Interior Gateway
Protocol (IGP) areas and Autonomous Systems (ASs).
ERO: Explicit Route Object
EXRS: Explicit Exclusion Route Subobject
IGP: Interior Gateway Protocol. Either of the two routing
protocols, Open Shortest Path First (OSPF) or Intermediate System
to Intermediate System (IS-IS).
IS-IS: Intermediate System to Intermediate System.
OSPF: Open Shortest Path First.
PCE: Path Computation Element. An entity (component, application,
or network node) that is capable of computing a network path or
route based on a network graph and applying computational
constraints.
PCEP: Path Computation Element Protocol.
RSVP: Resource Reservation Protocol
TE LSP: Traffic Engineering Label Switched Path.
XRO: Exclude Route Object
3. Subobjects for Domains
3.1. Domains
[RFC4726] and [RFC4655] define domain as a separate administrative or
geographic environment within the network. A domain may be further
defined as a zone of routing or computational ability. Under these
definitions a domain might be categorized as an AS or an IGP area.
As per [RFC3209], an abstract node is a group of nodes whose internal
topology is opaque to the ingress node of the LSP. Using this
concept of abstraction, an explicitly routed LSP can be specified as
a sequence of IP prefixes or a sequence of Autonomous Systems. In
this document we extend the notion to include IGP area and 4-Byte AS
number.
The sub-objects MAY appear in RSVP-TE, notably in -
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o Explicit Route Object (ERO): As per [RFC3209], an explicit route
is a particular path in the network topology including abstract
nodes (domains).
o Exclude Route Object (XRO): As per [RFC4874], an exclude route
identifies a list of abstract nodes (domains) that should not be
traversed along the path of the LSP being established.
o Explicit Exclusion Route Subobject (EXRS): As per [RFC4874], used
to specify exclusion of certain abstract nodes between a specific
pair of nodes. EXRS are a subobject carried inside the ERO.
These subobjects are used to specify the domains that must be
excluded between two abstract nodes.
3.2. Explicit Route Object (ERO)'s Subobjects
As stated in [RFC3209], an explicit route is a particular path in the
network topology. In addition to the ability to identify specific
nodes along the path, an explicit route can identify a group of nodes
(abstract nodes) that must be traversed along the path.
Some subobjects are defined in [RFC3209], [RFC3473], [RFC3477],
[RFC4874] and [RFC5553] but new subobjects related to domains are
needed.
The following subobject types are used in ERO.
Type Subobject
1 IPv4 prefix
2 IPv6 prefix
3 Label
4 Unnumbered Interface ID
32 Autonomous system number (2 Byte)
33 Explicit Exclusion (EXRS)
34 SRLG
64 IPv4 Path Key
65 IPv6 Path Key
This document extends the above list to support 4-Byte AS numbers and
IGP Areas.
Type Subobject
TBD Autonomous system number (4 Byte)
TBD OSPF Area id
TBD ISIS Area id
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3.2.1. Autonomous system
[RFC3209] already defines 2-Byte AS number.
To support 4-Byte AS numbers as per [RFC6793], the following
subobject is defined:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AS-ID (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L: The L bit is an attribute of the subobject as defined in
[RFC3209].
Type: (TBA by IANA) indicating a 4-Byte AS Number.
Length: 8 (Total length of the subobject in bytes).
Reserved: Zero at transmission, ignored at receipt.
AS-ID: The 4-Byte AS Number. Note that if 2-Byte AS numbers are in
use, the low order bits (16 through 31) should be used and the
high order bits (0 through 15) should be set to zero.
3.2.2. IGP Area
Since the length and format of Area-id is different for OSPF and
ISIS, the following two subobjects are defined:
For OSPF, the area-id is a 32 bit number. The subobject is encoded
as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OSPF Area Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L: The L bit is an attribute of the subobject as defined in
[RFC3209].
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Type: (TBA by IANA) indicating a 4-Byte OSPF Area ID.
Length: 8 (Total length of the subobject in bytes).
Reserved: Zero at transmission, ignored at receipt.
OSPF Area Id: The 4-Byte OSPF Area ID.
For IS-IS, the area-id is of variable length and thus the length of
the subobject is variable. The Area-id is as described in IS-IS by
ISO standard [ISO10589]. The subobject is encoded as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Type | Length | Area-Len | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// IS-IS Area ID //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L: The L bit is an attribute of the subobject as defined in
[RFC3209].
Type: (TBA by IANA) indicating IS-IS Area ID.
Length: Variable. As per [RFC3209], the total length of the
subobject in bytes, including the L, Type and Length fields. The
Length MUST be at least 4, and MUST be a multiple of 4.
Area-Len: Variable (Length of the actual (non-padded) IS-IS Area
Identifier in octets; Valid values are from 2 to 11 inclusive).
Reserved: Zero at transmission, ignored at receipt.
IS-IS Area Id: The variable-length IS-IS area identifier. Padded
with trailing zeroes to a four-byte boundary.
3.2.3. Mode of Operation
The new subobjects to support 4-Byte AS and IGP (OSPF / ISIS) Area
MAY also be used in the ERO to specify an abstract node (a group of
nodes whose internal topology is opaque to the ingress node of the
LSP).
All the rules of processing (for example Next Hop Selection, L bit
processing, unrecognized subobjects etc) are as per the [RFC3209].
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3.3. Exclude Route Object (XRO)'s Subobjects
As stated in [RFC4874], the exclude route identifies a list of
abstract nodes that should not be traversed along the path of the LSP
being established.
Some subobjects are defined in [RFC3209], [RFC3477], [RFC4874] and
[RFC6001] but new subobjects related to domains are needed.
The following subobject types are used in XRO.
Type Subobject
1 IPv4 prefix
2 IPv6 prefix
3 Label
4 Unnumbered Interface ID
32 Autonomous system number (2 Byte)
34 SRLG
This document extends the above list to support 4-Byte AS numbers and
IGP Areas.
Type Subobject
TBD Autonomous system number (4 Byte)
TBD OSPF Area id
TBD ISIS Area id
3.3.1. Autonomous system
[RFC3209] and [RFC4874] already define a 2-Byte AS number.
To support 4-Byte AS numbers as per [RFC6793], a subobject is with
the same format as defined in Section 3.2.1 with following
difference:
The meaning of the L bit (similar to [RFC4874]).
0: indicates that the abstract node (AS) specified MUST be excluded.
1: indicates that the abstract node (AS) specified SHOULD be avoided.
3.3.2. IGP Area
Since the length and format of Area-id is different for OSPF and
ISIS, the following two subobjects are defined:
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For OSPF, the area-id is a 32 bit number. Subobjects for OSPF and
IS-IS are of the same format as defined in Section 3.2.2 with
following difference:
The meaning of the L bit (similar to [RFC4874]).
0: indicates that the abstract node (OSPF or IS-IS Area) specified
MUST be excluded.
1: indicates that the abstract node (OSPF or IS-IS Area) specified
SHOULD be avoided.
3.3.3. Mode of Operation
The new subobjects to support 4-Byte AS and IGP (OSPF / ISIS) Area
MAY also be used in the XRO to specify exclusion of an abstract node
(a group of nodes whose internal topology is opaque to the ingress
node of the LSP).
All the rules of processing are as per the [RFC4874].
3.4. Explicit Exclusion Route Subobject
As per [RFC4874], the Explicit Exclusion Route defines abstract nodes
or resources that must not or should not be used on the path between
two inclusive abstract nodes or resources in the explicit route.
EXRS is an ERO subobject that contains one or more subobjects of its
own, called EXRS subobjects.
The EXRS subobject may carry any of the subobjects defined for XRO,
thus the new subobjects to support 4-Byte AS and IGP (OSPF / ISIS)
Area MAY also be used in the EXRS. The meanings of the fields of the
new XRO subobjects are unchanged when the subobjects are included in
an EXRS, except that scope of the exclusion is limited to the single
hop between the previous and subsequent elements in the ERO.
All the rules of processing are as per the [RFC4874].
4. Interaction with Path Computation Element (PCE)
The domain subobjects to be used in Path Computation Element Protocol
(PCEP) are referred to in [PCE-DOMAIN]. Note that the new domain
subobjects follow the principle that subobjects used in PCEP
[RFC5440] are identical to the subobjects used in RSVP-TE and thus
are interchangeable between PCEP and RSVP-TE.
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5. IANA Considerations
5.1. New Subobjects
IANA registry: RSVP PARAMETERS
Subsection: Class Names, Class Numbers, and Class Types
IANA is requested to add further subobjects to the existing entry
for:
20 EXPLICIT_ROUTE
232 EXCLUDE_ROUTE
Subobject Type Reference
TBA 4-Byte AS number [This I.D.]
TBA OSPF Area ID [This I.D.]
TBA IS-IS Area ID [This I.D.]
6. Security Considerations
Security considerations for MPLS-TE and GMPLS signaling are covered
in [RFC3209] and [RFC3473]. This document does not introduce any new
messages or any substantive new processing, and so those security
considerations continue to apply.
The route exclusion security consideration are covered in [RFC4874]
and continue to apply.
7. Acknowledgments
We would like to thank Adrian Farrel, Lou Berger, George Swallow,
Chirag Shah, Reeja Paul Sandeep Boina and Avantika for their useful
comments and suggestions.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
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[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
in Resource ReSerVation Protocol - Traffic Engineering
(RSVP-TE)", RFC 3477, January 2003.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
[RFC4726] Farrel, A., Vasseur, J., and A. Ayyangar, "A Framework for
Inter-Domain Multiprotocol Label Switching Traffic
Engineering", RFC 4726, November 2006.
[RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes -
Extension to Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE)", RFC 4874, April 2007.
[RFC5152] Vasseur, JP., Ayyangar, A., and R. Zhang, "A Per-Domain
Path Computation Method for Establishing Inter-Domain
Traffic Engineering (TE) Label Switched Paths (LSPs)", RFC
5152, February 2008.
[RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element
(PCE) Communication Protocol (PCEP)", RFC 5440, March
2009.
[RFC5553] Farrel, A., Bradford, R., and JP. Vasseur, "Resource
Reservation Protocol (RSVP) Extensions for Path Key
Support", RFC 5553, May 2009.
[RFC6001] Papadimitriou, D., Vigoureux, M., Shiomoto, K., Brungard,
D., and JL. Le Roux, "Generalized MPLS (GMPLS) Protocol
Extensions for Multi-Layer and Multi-Region Networks (MLN/
MRN)", RFC 6001, October 2010.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793, December
2012.
[PCE-DOMAIN]
Dhody, D., Palle, U., and R. Casellas, "Standard
Representation Of Domain Sequence. (draft-ietf-pce-pcep-
domain-sequence)", July 2014.
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[ISO10589]
ISO, "Intermediate system to Intermediate system routing
information exchange protocol for use in conjunction with
the Protocol for providing the Connectionless-mode Network
Service (ISO 8473)", ISO/IEC 10589:2002, 1992.
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Appendix A. Examples
These examples are for illustration purposes only, to show how the
new subobjects may be encoded.
A.1. Inter-Area LSP Path Setup
In an inter-area LSP path setup where the ingress and the egress
belong to different IGP areas within the same AS, the domain
subobjects MAY be represented using an ordered list of IGP area
subobjects in an ERO.
D2 Area D
|
|
D1
|
|
********BD1******
* | *
* | * Area C
Area A * | *
* | *
Ingress------A1-----ABF1------B1------BC1------C1------Egress
/ * | *
/ * | *
/ * Area | B *
F1 * | *
/ ********BE1******
/ |
/ |
F2 E1
|
Area F |
E2 Area E
* All IGP Area in one AS (AS 100)
Figure 1: Domain Corresponding to IGP Area
As per Figure 1, the signaling at Ingress MAY be -
ERO:(A1, ABF1, Area B, Area C, Egress); or
ERO:(A1, ABF1, AS 100, Area B, AS 100, Area C, Egress).
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The AS subobject is optional and it MAY be skipped. An RSVP-TE
implementation should be able to understand both notations and there
is no change in the processing rules as mentioned in [RFC3209].
A.2. Inter-AS LSP Path Setup
A.2.1. Example 1
In an inter-AS LSP path setup where the ingress and the egress belong
to different AS, the domain subobjects MAY be represented using an
ordered list of AS subobjects in an ERO.
AS A AS E AS C
<-------------> <----------> <------------->
A4----------E1---E2---E3---------C4
/ / \
/ / \
/ / AS B \
/ / <----------> \
Ingress------A1---A2------B1---B2---B3------C1---C2------Egress
\ / /
\ / /
\ / /
\ / /
A3----------D1---D2---D3---------C3
<---------->
AS D
* All AS have one area (area 0)
Figure 2: Domain Corresponding to AS
As per Figure 2, the signaling at Ingress MAY be -
ERO:(A1, A2, AS B, AS C, Egress); or
ERO:(A1, A2, AS B, Area 0, AS C, Area 0, Egress).
Each AS has a single IGP area (area 0), Area subobject is optional
and it MAY be skipped as AS is enough to uniquely identify a domain.
An RSVP-TE implementation should be able to understand both notations
and there is no change in the processing rules as mentioned in
[RFC3209].
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Note that to get a domain disjoint path, the ingress may also signal
the backup path with -
XRO:(AS B)
A.2.2. Example 2
As shown in Figure 3, where AS 200 is made up of multiple areas, the
signaling MAY include both AS and Area subobject to uniquely identify
a domain.
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Ingress *
| *
| *
X1 *
| \ *
| * \
|* \
* | \ Inter-AS
AS 100 * | \ Link
* | \
* | \
* | \
| D2 Area D
AS 200 | |
| |
Inter | D1
-AS | |
Link | |
A3 ********BD1******
| * | *
| * | * Area C
| Area A * | *
| * | *
A2------A1------AB1------B1------BC1------C1------Egress
* | *
* | *
* | *
* Area | B *
********BE1******
|
|
E1
|
|
E2 Area E
Figure 3: Domain Corresponding to AS and Area
As per Figure 3, the signaling at Ingress MAY be -
ERO:(X1, AS 200, Area D, Area B, Area C, Egress).
The combination of both an AS and an Area uniquely identifies a
domain, note that an Area domain identifier always belongs to the
previous AS that appears before it or, if no AS subobjects are
present, it is assumed to be the current AS. Also note that there
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are no changes in the processing rules as mentioned in [RFC3209] with
respect to subobjects.
Authors' Addresses
Dhruv Dhody
Huawei Technologies
Leela Palace
Bangalore, Karnataka 560008
INDIA
EMail: dhruv.ietf@gmail.com
Udayasree Palle
Huawei Technologies
Leela Palace
Bangalore, Karnataka 560008
INDIA
EMail: udayasree.palle@huawei.com
Venugopal Reddy Kondreddy
Huawei Technologies
Leela Palace
Bangalore, Karnataka 560008
INDIA
EMail: venugopalreddyk@huawei.com
Ramon Casellas
CTTC
Av. Carl Friedrich Gauss n7
Castelldefels, Barcelona 08860
SPAIN
EMail: ramon.casellas@cttc.es
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