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IETF RFC 4972
Routing Extensions for Discovery of Multiprotocol (MPLS) Label Switch Router (LSR) Traffic Engineering (TE) Mesh Membership
Last modified on Tuesday, July 31st, 2007
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Network Working Group JP. Vasseur, Ed.
Request for Comments: 4972 Cisco Systems, Inc
Category: Standards Track JL. Leroux, Ed.
France Telecom
S. Yasukawa
NTT
S. Previdi
P. Psenak
Cisco Systems, Inc
P. Mabbey
Comcast
July 2007
Routing Extensions for Discovery of Multiprotocol (MPLS)
Label Switch Router (LSR) Traffic Engineering (TE) Mesh Membership
 Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright © The IETF Trust (2007).
Abstract
The setup of a full mesh of Multi-Protocol Label Switching (MPLS)
Traffic Engineering (TE) Label Switched Paths (LSP) among a set of
Label Switch Routers (LSR) is a common deployment scenario of MPLS
Traffic Engineering either for bandwidth optimization, bandwidth
guarantees or fast rerouting with MPLS Fast Reroute. Such deployment
may require the configuration of a potentially large number of TE
LSPs (on the order of the square of the number of LSRs). This
document specifies Interior Gateway Protocol (IGP) routing extensions
for Intermediate System-to-Intermediate System (IS-IS) and Open
Shortest Path First (OSPF) so as to provide an automatic discovery of
the set of LSRs members of a mesh in order to automate the creation
of such mesh of TE LSPs.
Vasseur, et al. Standards Track PAGE 1 
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
Table of Contents
1. Introduction ....................................................2
2. Definitions .....................................................3
2.1. Conventions Used in This Document ..........................4
3. Description of a TE Mesh-Group ..................................4
4. TE-MESH-GROUP TLV Formats .......................................4
4.1. OSPF TE-MESH-GROUP TLV Format ..............................4
4.2. IS-IS TE-MESH-GROUP Sub-TLV Format .........................7
5. Elements of Procedure ...........................................9
5.1. OSPF .......................................................9
5.2. IS-IS .....................................................10
6. Backward Compatibility .........................................11
7. IANA Considerations ............................................11
7.1. OSPF ......................................................11
7.2. IS-IS .....................................................11
8. Security Considerations ........................................12
9. Acknowledgements ...............................................12
10. References ....................................................12
10.1. Normative References .....................................12
10.2. Informative References ...................................13
1. Introduction
There are two well-known approaches in deploying MPLS Traffic
Engineering:
(1) The so-called "strategic" approach that consists of setting up a
full mesh of TE LSPs between a set of LSRs.
(2) The so-called "tactical" approach, where a set of TE LSPs are
provisioned on well-identified "hot spots" in order to alleviate a
congestion resulting, for instance, from an unexpected traffic growth
in some parts of the network.
The setup of a full mesh of TE LSPs among a set of LSRs is a common
deployment scenario of MPLS Traffic Engineering either for bandwidth
optimization, bandwidth guarantees, or fast rerouting with MPLS Fast
Reroute. Setting up a full mesh of TE LSPs between N LSRs requires
the configuration of a potentially large number of TE LSPs (O(N^2)).
Furthermore, the addition of any new LSR in the mesh requires the
configuration of N additional TE LSPs on the new LSR and one new TE
LSP on every LSR of the existing mesh destined to this new LSR, which
gives a total of 2*N TE LSPs to be configured. Such an operation is
not only time consuming but also risky (prone to misconfiguration)
for Service Providers. Hence, an automatic mechanism for setting up
TE LSPs meshes is desirable and requires the ability to automatically
discover the set of LSRs that belong to the mesh. This document
Vasseur, et al. Standards Track PAGE 2
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
specifies routing extensions so as to automatically discover the
members of a mesh, also referred to as a "TE mesh-group". Note that
the mechanism(s) needed for the dynamic creation of TE LSPs is
implementation specific and outside the scope of this document.
Routing extensions have been defined in [RFC 4970] and [RFC 4971] in
order to advertise router capabilities. This document specifies IGP
(OSPF and IS-IS) TE Mesh Group (Type Length Value) TLVs allowing for
the automatic discovery of a TE mesh-group members, to be carried in
the OSPF Router Information (Link State Advertisement) LSA [RFC 4970]
and IS-IS Router Capability TLV [RFC 4971]. The routing extensions
specified in this document provide the ability to signal multiple TE
mesh groups. An LSR may belong to more than one TE mesh-group(s).
There are relatively tight real-time constraints on the operation of
IGPs (such as OSPF and IS-IS). For this reason, some care needs to
be applied when proposing to carry additional information in an IGP.
The information described in this document is both relatively small
in total volume (compared with other information already carried in
IGPs), and also relatively stable (i.e., changes are based on
configuration changes, but not on dynamic events within the network,
or on dynamic triggers, such as the leaking of information from other
routing protocols or routing protocol instances).
2. Definitions
Terminology used in this document
IGP: Interior Gateway Protocol
IGP Area: OSPF area or IS-IS level
IS-IS: Intermediate System-to-Intermediate System (IS-IS)
LSR: Label Switch Router
OSPF: Open Shortest Path First
OSPF LSA: OSPF Link State Advertisement
TE LSP: Traffic Engineering Label Switched Path
TE LSP head-end: head/source of the TE LSP
TE LSP tail-end: tail/destination of the TE LSP.
TLV: Type Length Value
Vasseur, et al. Standards Track PAGE 3
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
2.1. Conventions Used in This Document
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 RFC 2119 [RFC 2119].
3. Description of a TE Mesh-Group
A TE mesh-group is defined as a group of LSRs that are connected by a
full mesh of TE LSPs. Routing extensions are specified in this
document, allowing for dynamic discovery of the TE mesh-group
members. Procedures are also specified for a member to join and
leave a TE mesh-group. For each TE mesh-group membership announced
by an LSR, the following information is advertised:
- A mesh-group number identifying the TE mesh-group that the LSR
belongs to,
- A tail-end address (used as the TE LSP Tail-end address by other
LSRs belonging to the same mesh-group),
- A tail-end name: a display string that is allocated to the tail-
end used to ease the TE-LSP naming.
4. TE-MESH-GROUP TLV Formats
4.1. OSPF TE-MESH-GROUP TLV Format
The TE-MESH-GROUP TLV is used to advertise the desire of an LSR to
join/leave a given TE mesh-group. No sub-TLV is currently defined
for the TE-MESH-GROUP TLV.
The OSPF TE-MESH-GROUP TLV (advertised in an OSPF router information
LSA defined in [RFC 4970]) has the following format:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Value //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 - OSPF TE-MESH-GROUP TLV format
Vasseur, et al. Standards Track PAGE 4
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
Where
Type: identifies the TLV type
Length: the length of the value field in octets
The format of the OSPF TE-MESH-GROUP TLV is the same as the TLV
format used by the Traffic Engineering Extensions to OSPF
(see[RFC 3630]). The TLV is padded to a four-octet alignment; padding
is not included in the length field (so a three-octet value would
have a length of three, but the total size of the TLV would be eight
octets). Nested TLVs are also 32-bit aligned. Unrecognized types
are ignored. All types between 32768 and 65535 are reserved for
vendor-specific extensions. All other undefined type codes are
reserved for future assignment by IANA.
The OSPF TE-MESH-GROUP TLV format for IPv4 (Figure 2) and IPv6
(Figure 3) is as follows:
TYPE: 3
LENGTH: Variable
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mesh-group-number 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tail-end IPv4 address 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length | Tail-end name 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mesh-group-number n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tail-end IPv4 address n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length | Tail-end name n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 - OSPF TE-MESH-GROUP TLV format (IPv4 Address)
Vasseur, et al. Standards Track PAGE 5
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
TYPE: 4
LENGTH: Variable
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mesh-group-number 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Tail-end IPv6 address 1 |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length | Tail-end name 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mesh-group-number n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Tail-end IPv6 address n |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length | Tail-end name n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3 - OSPF TE-MESH-GROUP TLV format (IPv6 Address)
The OSPF TE-MESH-GROUP TLV may contain one or more mesh-group
entries, where each entry corresponds to a TE mesh-group and is made
of the following fields:
- A mesh-group-number that identifies the mesh-group number.
- A Tail-end address: an IPv4 or IPv6 IP address to be used as a
tail-end TE LSP address by other LSRs belonging to the same mesh-
group.
- Name length field: An integer, expressed in octets, that indicates
the length of the Tail-end name before padding.
- A Tail-end name: A display string that is allocated to the Tail-
end. The field is of variable length field and is used to
facilitate the TE LSP identification.
Vasseur, et al. Standards Track PAGE 6
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
4.2. IS-IS TE-MESH-GROUP Sub-TLV Format
The TE-MESH-GROUP sub-TLV is used to advertise the desire of an LSR
to join/leave a given TE mesh-group. No sub-TLV is currently defined
for the TE-MESH-GROUP sub-TLV.
The IS-IS TE-MESH-GROUP sub-TLV (advertised in the IS-IS CAPABILITY
TLV defined in [RFC 4971]) is composed of 1 octet for the type, 1
octet specifying the TLV length and a value field. The format of the
TE-MESH-GROUP sub-TLV is identical to the TLV format used by the
Traffic Engineering Extensions for IS-IS [RFC 3784].
The IS-IS TE-MESH-GROUP sub-TLV format for IPv4 (Figure 4) and IPv6
(Figure 5) is as follows:
TYPE: 3
LENGTH: Variable
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mesh-group-number 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tail-end IPv4 address 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length | Tail-end name 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mesh-group-number n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tail-end IPv4 address n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length | Tail-end name n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4 - IS-IS TE-MESH-GROUP sub-TLV format (IPv4 Address)
Vasseur, et al. Standards Track PAGE 7
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
TYPE: 4
LENGTH: Variable
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mesh-group-number 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Tail-end IPv6 address 1 |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length | Tail-end name 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| mesh-group-number n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Tail-end IPv6 address n |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length | Tail-end name n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5 - IS-IS TE-MESH-GROUP sub-TLV format (IPv6 Address)
The IS-IS TE-MESH-GROUP sub-TLV may contain one or more mesh-group
entries where each entry correspond to a TE mesh-group and is made of
the following fields:
- A mesh-group-number that identifies the mesh-group number.
- A Tail-end address: an IPv4 or IPv6 IP address to be used as a
tail-end TE LSP address by other LSRs belonging to the same mesh-
group.
- Name length field: An integer, expressed in octets, that indicates
the length of the Tail-end name before padding.
- A Tail-end name: A display string that is allocated to the Tail-
end. The field is of variable length and is used to facilitate
the TE LSP identification.
Vasseur, et al. Standards Track PAGE 8
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
5. Elements of Procedure
The OSPF TE-MESH-GROUP TLV is carried within the OSPF Routing
Information LSA and the IS-IS TE-MESH-GROUP sub-TLV is carried within
the IS-IS Router capability TLV. As such, elements of procedure are
inherited from those defined in [RFC 4970] and [RFC 4971] for OSPF and
IS-IS respectively. Specifically, a router MUST originate a new
LSA/LSP whenever the content of this information changes, or whenever
required by regular routing procedure (e.g., updates).
The TE-MESH-GROUP TLV is OPTIONAL and MUST NOT include more than one
of each of the IPv4 instances or the IPv6 instance. If either the
IPv4 or the IPv6 OSPF TE-MESH-GROUP TLV occurs more than once within
the OSPF Router Information LSA, only the first instance is
processed, subsequent TLV(s) SHOULD be silently ignored. Similarly,
if either the IPv4 or the IPv6 IS-IS TE-MESH-GROUP sub-TLV occurs
more than once within the IS-IS Router capability TLV, only the first
instance is processed, subsequent TLV(s) SHOULD be silently ignored.
5.1. OSPF
The TE-MESH-GROUP TLV is advertised within an OSPF Router Information
opaque LSA (opaque type of 4, opaque ID of 0) for OSPFv2 [RFC 2328]
and within a new LSA (Router Information LSA) for OSPFv3 [RFC 2740].
The Router Information LSAs for OSPFv2 and OSPFv3 are defined in
[RFC 4970].
A router MUST originate a new OSPF router information LSA whenever
the content of any of the advertised TLV changes or whenever required
by the regular OSPF procedure (LSA update (every LSRefreshTime)). If
an LSR desires to join or leave a particular TE mesh group, it MUST
originate a new OSPF Router Information LSA comprising the updated
TE-MESH-GROUP TLV. In the case of a join, a new entry will be added
to the TE-MESH-GROUP TLV; conversely, if the LSR leaves, a mesh-group
the corresponding entry will be removed from the TE-MESH-GROUP TLV.
Note that both operations can be performed in the context of a single
LSA update. An implementation SHOULD be able to detect any change to
a previously received TE-MESH-GROUP TLV from a specific LSR.
As defined in [RFC 2370] for OSPVv2 and in [RFC 2740] for OSPFv3, the
flooding scope of the Router Information LSA is determined by the LSA
Opaque type for OSPFv2 and the values of the S1/S2 bits for OSPFv3.
For OSPFv2 Router Information opaque LSA:
- Link-local scope: type 9;
- Area-local scope: type 10;
Vasseur, et al. Standards Track PAGE 9
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
- Routing-domain scope: type 11. In this case, the flooding scope
is equivalent to the Type 5 LSA flooding scope.
For OSPFv3 Router Information LSA:
- Link-local scope: OSPFv3 Router Information LSA with the S1 and S2
bits cleared;
- Area-local scope: OSPFv3 Router Information LSA with the S1 bit
set and the S2 bit cleared;
- Routing-domain scope: OSPFv3 Router Information LSA with S1 bit
cleared and the S2 bit set.
A router may generate multiple OSPF Router Information LSAs with
different flooding scopes.
The TE-MESH-GROUP TLV may be advertised within an Area-local or
Routing-domain scope Router Information LSA, depending on the MPLS TE
mesh group profile:
- If the MPLS TE mesh-group is contained within a single area (all
the LSRs of the mesh-group are contained within a single area),
the TE-MESH-GROUP TLV MUST be generated within an Area-local
Router Information LSA.
- If the MPLS TE mesh-group spans multiple OSPF areas, the TE mesh-
group TLV MUST be generated within a Routing-domain scope router
information LSA.
5.2. IS-IS
The TE-MESH-GROUP sub-TLV is advertised within the IS-IS Router
CAPABILITY TLV defined in [RFC 4971]. An IS-IS router MUST originate
a new IS-IS LSP whenever the content of any of the advertised sub-TLV
changes or whenever required by regular IS-IS procedure (LSP
updates). If an LSR desires to join or leave a particular TE mesh
group, it MUST originate a new LSP comprising the refreshed IS-IS
Router capability TLV comprising the updated TE-MESH-GROUP sub-TLV.
In the case of a join, a new entry will be added to the TE-MESH-GROUP
sub-TLV; conversely, if the LSR leaves a mesh-group, the
corresponding entry will be deleted from the TE-MESH-GROUP sub-TLV.
Note that both operations can be performed in the context of a single
update. An implementation SHOULD be able to detect any change to a
previously received TE-MESH-GROUP sub-TLV from a specific LSR.
If the flooding scope of a TE-MESH-GROUP sub-TLV is limited to an
IS-IS level/area, the sub-TLV MUST not be leaked across level/area
Vasseur, et al. Standards Track PAGE 10
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
and the S flag of the Router CAPABILITY TLV MUST be cleared.
Conversely, if the flooding scope of a TE-MESH-GROUP sub-TLV is the
entire routing domain, the TLV MUST be leaked across IS-IS
levels/areas, and the S flag of the Router CAPABILITY TLV MUST be
set. In both cases, the flooding rules specified in [RFC 4971] apply.
As specified in [RFC 4971], a router may generate multiple IS-IS
Router CAPABILITY TLVs within an IS-IS LSP with different flooding
scopes.
6. Backward Compatibility
The TE-MESH-GROUP TLVs defined in this document do not introduce any
interoperability issue. For OSPF, a router not supporting the TE-
MESH-GROUP TLV SHOULD just silently ignore the TLV as specified in
[RFC 2370]. For an IS-IS, a router not supporting the TE-MESH-GROUP
sub-TLV SHOULD just silently ignore the sub-TLV.
7. IANA Considerations
7.1. OSPF
The registry for the Router Information LSA is defined in [RFC 4970].
IANA assigned a new OSPF TLV code-point for the TE-MESH-GROUP TLVs
carried within the Router Information LSA.
Value Sub-TLV References
----- -------- ----------
3 TE-MESH-GROUP TLV (IPv4) RFC 4972 (this doc)
4 TE-MESH-GROUP TLV (IPv6) RFC 4972 (this doc)
7.2. IS-IS
The registry for the Router Capability TLV is defined in [RFC 4971].
IANA assigned a new IS-IS sub-TLV code-point for the TE-MESH-GROUP
sub-TLVs carried within the IS-IS Router Capability TLV.
Value Sub-TLV References
----- -------- ----------
3 TE-MESH-GROUP TLV (IPv4) RFC 4972 (this doc)
4 TE-MESH-GROUP TLV (IPv6) RFC 4972 (this doc)
Vasseur, et al. Standards Track PAGE 11
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
8. Security Considerations
The function described in this document does not create any new
security issues for the OSPF and IS-IS protocols. Security
considerations are covered in [RFC 2328] and [RFC 2740] for the base
OSPF protocol and in [RFC 1195] for IS-IS. It must be noted that the
advertisement of "fake" TE Mesh Group membership(s) by a mis-
configured or malicious LSR Y would not have any major impact on the
network (other than overloading the IGP), such as triggering the set
up of new MPLS TE LSP: indeed, for a new TE LSP originated by another
LSR X destined to LSR Y to be set up, the same TE Mesh group
membership must be configured on both LSRs. Thus such fake
advertisement could not amplify any Denial of Service (DoS) attack.
9. Acknowledgements
We would like to thank Dean Cheng, Adrian Farrel, Yannick Le Louedec,
Dave Ward, Les Ginsberg, Stephen Nadas, Acee Lindem, Dimitri
Papadimitriou, and Lakshminath Dondeti for their useful comments.
10. References
10.1. Normative References
[RFC 4971] Vasseur, J-P., Ed., Shen, N., Ed., and R. Aggarwal, Ed.,
"Intermediate System to Intermediate System (IS-IS)
Extensions for Advertising Router Information", RFC 4971,
July 2007.
[RFC 4970] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 4970, July 2007.
[RFC 1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, December 1990.
[RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC 2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC 2370] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370, July
1998.
[RFC 2740] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", RFC
2740, December 1999.
Vasseur, et al. Standards Track PAGE 12
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
10.2. Informative References
[RFC 3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, September
2003.
[RFC 3784] Smit, H. and T. Li, "Intermediate System to Intermediate
System (IS-IS) Extensions for Traffic Engineering (TE)",
RFC 3784, June 2004.
Authors' Addresses
JP Vasseur (editor)
Cisco Systems, Inc
1414 Massachusetts Avenue
Boxborough, MA 01719
USA
EMail: jpv@cisco.com
JL Le Roux (editor)
France Telecom
2, Avenue Pierre-Marzin
Lanion, 22307
FRANCE
EMail: jeanlouis.leroux@orange-ftgroup.com
Seisho Yasukawa
NTT
3-1, Otemachi 2-Chome Chiyoda-ku
Tokyo, 100-8116
JAPAN
EMail: s.yasukawa@hco.ntt.co.jp
Stefano Previdi
Cisco Systems, Inc
Via Del Serafico 200
Roma, 00142
Italy
EMail: sprevidi@cisco.com
Vasseur, et al. Standards Track PAGE 13
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
Peter Psenak
Cisco Systems
Mlynske Nivy 43
821 09
Bratislava
Slovakia
EMail: ppsenak@cisco.com
Paul Mabbey
Comcast Cable
4100 E. Dry Creek Rd
Centennial, CO 80122
USA
EMail: Paul_Mabey@cable.comcast.com
Vasseur, et al. Standards Track PAGE 14
RFC 4972 Discovery of MPLS LSR TE Mesh Membership July 2007
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Internet Society.
Vasseur, et al. Standards Track PAGE 15
Routing Extensions for Discovery of Multiprotocol (MPLS) Label Switch Router (LSR) Traffic Engineering (TE) Mesh Membership
RFC TOTAL SIZE: 32044 bytes
PUBLICATION DATE: Tuesday, July 31st, 2007
LEGAL RIGHTS: The IETF Trust (see BCP 78)
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