draft-ietf-ccamp-gmpls-general-constraints-ospf-te-03.txt   draft-ietf-ccamp-gmpls-general-constraints-ospf-te-04.txt 
Network work group Fatai Zhang Network work group Fatai Zhang
Internet Draft Young Lee Internet Draft Young Lee
Intended status: Standards Track Jianrui Han Intended status: Standards Track Jianrui Han
Huawei Huawei
G. Bernstein G. Bernstein
Grotto Networking Grotto Networking
Yunbin Xu Yunbin Xu
CATR CATR
Expires: December 19, 2012 June 19, 2012 Expires: January 6, 2013 July 6, 2012
OSPF-TE Extensions for General Network Element Constraints OSPF-TE Extensions for General Network Element Constraints
draft-ietf-ccamp-gmpls-general-constraints-ospf-te-03.txt draft-ietf-ccamp-gmpls-general-constraints-ospf-te-04.txt
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with This Internet-Draft is submitted to IETF in full conformance with
the provisions of BCP 78 and BCP 79. the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
Internet-Drafts are draft documents valid for a maximum of six Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other months and may be updated, replaced, or obsoleted by other documents
documents at any time. It is inappropriate to use Internet-Drafts at any time. It is inappropriate to use Internet-Drafts as
as reference material or to cite them other than as "work in reference material or to cite them other than as "work in progress."
progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html
This Internet-Draft will expire on December 19, 2012. This Internet-Draft will expire on January 6, 2012.
Copyright Notice
Copyright (c) 2012 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
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with
respect to this document. Code Components extracted from this
document must include Simplified BSD License text as described in
Section 4.e of the Trust Legal Provisions and are provided without
warranty as described in the Simplified BSD License.
Abstract Abstract
Generalized Multiprotocol Label Switching can be used to control a Generalized Multiprotocol Label Switching can be used to control a
wide variety of technologies including packet switching (e.g., MPLS), wide variety of technologies including packet switching (e.g., MPLS),
time-division (e.g., SONET/SDH, OTN), wavelength (lambdas), and time-division (e.g., SONET/SDH, OTN), wavelength (lambdas), and
spatial switching (e.g., incoming port or fiber to outgoing port or spatial switching (e.g., incoming port or fiber to outgoing port or
fiber). In some of these technologies network elements and links may fiber). In some of these technologies network elements and links may
impose additional routing constraints such as asymmetric switch impose additional routing constraints such as asymmetric switch
connectivity, non-local label assignment, and label range connectivity, non-local label assignment, and label range
limitations on links. This document describes OSPF routing protocol limitations on links. This document describes OSPF routing protocol
extensions to support these kinds of constraints under the control extensions to support these kinds of constraints under the control
of Generalized MPLS (GMPLS). of Generalized MPLS (GMPLS).
skipping to change at page 2, line 23 skipping to change at page 2, line 36
of Generalized MPLS (GMPLS). of Generalized MPLS (GMPLS).
Conventions used in this document Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [RFC2119]. document are to be interpreted as described in RFC-2119 [RFC2119].
Table of Contents Table of Contents
1. Introduction...................................................2 1. Introduction...................................................3
2. Node Information...............................................3 2. Node Information...............................................3
2.1. Connectivity Matrix.......................................4 2.1. Connectivity Matrix.......................................4
3. Link Information...............................................4 3. Link Information...............................................5
3.1. Port Label Restrictions...................................5 3.1. Port Label Restrictions...................................5
3.2. Available Labels..........................................5
3.3. Shared Backup Labels......................................6
4. Routing Procedures.............................................6 4. Routing Procedures.............................................6
5. Scalability and Timeliness.....................................7 5. Scalability and Timeliness.....................................6
5.1. Different Sub-TLVs into Multiple LSAs.....................7 5.1. Different Sub-TLVs into Multiple LSAs.....................7
5.2. Decomposing a Connectivity Matrix into Multiple Matrices..8 5.2. Decomposing a Connectivity Matrix into Multiple Matrices..7
6. Security Considerations........................................8 6. Security Considerations........................................7
7. IANA Considerations............................................8 7. IANA Considerations............................................8
7.1. Node Information..........................................9 7.1. Node Information..........................................8
7.2. Link Information..........................................9 7.2. Link Information..........................................8
8. References.....................................................9
8.1. Normative References......................................9 8. References.....................................................8
8.2. Informative References...................................10 8.1. Normative References......................................8
9. Authors' Addresses ............................................10 8.2. Informative References....................................9
Acknowledgment...................................................12 9. Authors' Addresses .............................................9
Acknowledgment...................................................11
1. Introduction 1. Introduction
Some data plane technologies that wish to make use of a GMPLS Some data plane technologies that wish to make use of a GMPLS
control plane contain additional constraints on switching capability control plane contain additional constraints on switching capability
and label assignment. In addition, some of these technologies should and label assignment. In addition, some of these technologies should
be capable of performing non-local label assignment based on the be capable of performing non-local label assignment based on the
nature of the technology, e.g., wavelength continuity constraint in nature of the technology, e.g., wavelength continuity constraint in
WSON [RFC6163]. Such constraints can lead to the requirement for WSON [RFC6163]. Such constraints can lead to the requirement for
link by link label availability in path computation and label link by link label availability in path computation and label
skipping to change at page 5, line 4 skipping to change at page 5, line 20
(ISCD), Link Protection Type, Shared Risk Link Group Information (ISCD), Link Protection Type, Shared Risk Link Group Information
(SRLG), and Traffic Engineering Metric are among the typical link (SRLG), and Traffic Engineering Metric are among the typical link
sub-TLVs. sub-TLVs.
Per [GEN-Encode], we add the following additional link sub-TLVs to Per [GEN-Encode], we add the following additional link sub-TLVs to
the link-TLV in this document. the link-TLV in this document.
Sub-TLV Type Length Name Sub-TLV Type Length Name
TBD variable Port Label Restrictions TBD variable Port Label Restrictions
TBD variable Available Labels
TBD variable Shared Backup Labels
Generally all the sub-TLVs above are optional, which depends on the Generally all the sub-TLVs above are optional, which depends on the
control plane implementations. If it is default no restrictions on control plane implementations. If it is default no restrictions on
labels, Port Label Restrictions sub-TLV may not appear in the LSAs. labels, Port Label Restrictions sub-TLV may not appear in the LSAs.
In order to be able to compute label assignment, Available Labels
sub-TLV may appear in the LSAs. For example, in WSON networks,
without available wavelength information, path computation need
guess what lambdas may be available (high blocking probability or
distributed wavelength assignment may be used).
3.1. Port Label Restrictions 3.1. Port Label Restrictions
Port label restrictions describe the label restrictions that the Port label restrictions describe the label restrictions that the
network element (node) and link may impose on a port. These network element (node) and link may impose on a port. These
restrictions represent what labels may or may not be used on a link restrictions represent what labels may or may not be used on a link
and are intended to be relatively static. More dynamic information and are intended to be relatively static. More dynamic information
is contained in the information on available labels. Port label is contained in the information on available labels. Port label
restrictions are specified relative to the port in general or to a restrictions are specified relative to the port in general or to a
specific connectivity matrix for increased modeling flexibility. specific connectivity matrix for increased modeling flexibility.
skipping to change at page 5, line 40 skipping to change at page 6, line 5
These restrictions represent what wavelength may or may not be used These restrictions represent what wavelength may or may not be used
on a link and are relatively static. The detailed information about on a link and are relatively static. The detailed information about
Port label restrictions is described in [WSON-Info]. Port label restrictions is described in [WSON-Info].
The Port Label Restrictions is a sub-TLV (the type is TBD by IANA) The Port Label Restrictions is a sub-TLV (the type is TBD by IANA)
of the Link TLV. The length is the length of value field in octets. of the Link TLV. The length is the length of value field in octets.
The meaning and format of this sub-TLV are defined in Section 5.4 of The meaning and format of this sub-TLV are defined in Section 5.4 of
[GEN-Encode]. The Port Label Restrictions sub-TLV may occur more [GEN-Encode]. The Port Label Restrictions sub-TLV may occur more
than once to specify a complex port constraint within the link TLV. than once to specify a complex port constraint within the link TLV.
3.2. Available Labels
Available Labels indicates the labels available for use on a link as
described in [GEN-Encode]. The Available Labels is a sub-TLV (the
type is TBD by IANA) of the Link TLV. The length is the length of
value field in octets. The meaning and format of this sub-TLV are
defined in Section 5.1 of [GEN-Encode]. The Available Labels sub-TLV
may occur at most once within the link TLV.
Note that there are five approaches for Label Set which is used to
represent the Available Labels described in [GEN-Encode]. Usually,
it depends on the implementation to one of the approaches. In WSON
networks, considering that the continuity of the available or
unavailable wavelength set can be scattered for the dynamic
wavelength availability, so it may burden the routing to reorganize
the wavelength set information when the Inclusive (/Exclusive) List
(/Range) approaches are used to represent Available Wavelengths
information. Therefore, it is RECOMMENDED that only the Bitmap Set
be used for representation Available Wavelengths information.
The "Base Label" and "Last Label" in label set defined in [GEN-
Encode] corresponds to base wavelength label and last wavelength
label in WSON, the format of which is described 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Grid | C.S. | Reserved | n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The detailed information related to wavelength label can be referred
to [RFC6205].
3.3. Shared Backup Labels
Shared Backup Labels indicates the labels available for shared
backup use on a link as described in [GEN-Encode].
The Shared Backup Labels is a sub-TLV (the type is TBD by IANA) of
the Link TLV. The length is the length of value field in octets. The
meaning and format of this sub-TLV are defined in Section 5.2 of
[GEN-Encode]. The Shared Backup Labels sub-TLV may occur at most
once within the link TLV.
4. Routing Procedures 4. Routing Procedures
All the sub-TLVs are nested to top-level TLV(s) and contained in All the sub-TLVs are nested to top-level TLV(s) and contained in
Opaque LSAs. The flooding of Opaque LSAs must follow the rules Opaque LSAs. The flooding of Opaque LSAs must follow the rules
specified in [RFC2328], [RFC5250], [RFC3630], [RFC4203]. specified in [RFC2328], [RFC5250], [RFC3630], [RFC4203].
Considering the routing scalability issues in some cases, the Considering the routing scalability issues in some cases, the
routing protocol should be capable of supporting the separation of routing protocol should be capable of supporting the separation of
dynamic information from relatively static information to avoid dynamic information from relatively static information to avoid
unnecessary updates of static information when dynamic information unnecessary updates of static information when dynamic information
skipping to change at page 7, line 14 skipping to change at page 6, line 27
nested to top-level TLV ([RFC3630 and RFC5876]), and advertise them nested to top-level TLV ([RFC3630 and RFC5876]), and advertise them
in the separate OSPF TE LSAs. in the separate OSPF TE LSAs.
For node information, since the Connectivity Matrix information is For node information, since the Connectivity Matrix information is
static, the LSA containing the Generic Node Attribute TLV can be static, the LSA containing the Generic Node Attribute TLV can be
updated with a lower frequency to avoid unnecessary updates. updated with a lower frequency to avoid unnecessary updates.
For link information, a mechanism MAY be applied such that static For link information, a mechanism MAY be applied such that static
information and dynamic information of one TE link are contained in information and dynamic information of one TE link are contained in
separate Opaque LSAs. For example, the Port Label Restrictions separate Opaque LSAs. For example, the Port Label Restrictions
information sub-TLV and Available Labels information sub-TLV can be information sub-TLV could be nested to the top level link TLVs and
nested to the top level link TLVs and advertised in the separate advertised in the separate LSAs.
LSAs.
Note that as with other TE information, an implementation SHOULD Note that as with other TE information, an implementation SHOULD
take measures to avoid rapid and frequent updates of routing take measures to avoid rapid and frequent updates of routing
information that could cause the routing network to become swamped. information that could cause the routing network to become swamped.
A threshold mechanism MAY be applied such that updates are only A threshold mechanism MAY be applied such that updates are only
flooded when a number of changes have been made to the label flooded when a number of changes have been made to the label
availability information (e.g., wavelength availability) within a availability information (e.g., wavelength availability) within a
specific time. Such mechanisms MUST be configurable if they are specific time. Such mechanisms MUST be configurable if they are
implemented. implemented.
skipping to change at page 7, line 41 skipping to change at page 7, line 7
very large systems, in terms of label count or ports can be very very large systems, in terms of label count or ports can be very
efficiently encoded. However there has been concern expressed that efficiently encoded. However there has been concern expressed that
some possible systems may produce LSAs that exceed the IP Maximum some possible systems may produce LSAs that exceed the IP Maximum
Transmission Unit (MTU) and that methods be given to allow for the Transmission Unit (MTU) and that methods be given to allow for the
splitting of general constraint LSAs into smaller LSA that are under splitting of general constraint LSAs into smaller LSA that are under
the MTU limit. This section presents a set of techniques that can be the MTU limit. This section presents a set of techniques that can be
used for this purpose. used for this purpose.
5.1. Different Sub-TLVs into Multiple LSAs 5.1. Different Sub-TLVs into Multiple LSAs
Four sub-TLVs are defined in this document: Two sub-TLVs are defined in this document:
1. Connectivity Matrix (Generic Node Attribute TLV) 1. Connectivity Matrix (Generic Node Attribute TLV)
2. Port Label Restrictions (Link TLV) 2. Port Label Restrictions (Link TLV)
3. Available Labels (Link TLV)
4. Shared Backup Labels (Link TLV)
Except for the Connectivity Matrix all these are carried in an Link Except for the Connectivity Matrix all these are carried in an Link
TLV of which there can be at most one in an LSA [RFC3630]. Of these TLV of which there can be at most one in an LSA [RFC3630]. Of these
sub-TLVs the Port Label Restrictions are relatively static, i.e., sub-TLVs the Port Label Restrictions are relatively static, i.e.,
only would change with hardware changes or significant system only would change with hardware changes or significant system
reconfiguration. While the Available Labels and Shared Backup Labels reconfiguration.
are dynamic, meaning that they may change with LSP setup or teardown
through the system. The most important technique for scalability and
OSPF bandwidth reduction is to separate the dynamic information sub-
TLVs from the static information sub-TLVs and advertise them in
separate OSPF TE LSAs[RFC3630 and RFC5250].
5.2. Decomposing a Connectivity Matrix into Multiple Matrices 5.2. Decomposing a Connectivity Matrix into Multiple Matrices
In the highly unlikely event that a Connectivity matrix sub-TLV by In the highly unlikely event that a Connectivity matrix sub-TLV by
itself would result in an LSA exceeding the MTU, a single large itself would result in an LSA exceeding the MTU, a single large
matrix can be decomposed into sub-matrices. Per [GEN-Encode] a matrix can be decomposed into sub-matrices. Per [GEN-Encode] a
connectivity matrix just consists of pairs of input and output ports connectivity matrix just consists of pairs of input and output ports
that can reach each other and hence such this decomposition would be that can reach each other and hence such this decomposition would be
straightforward. Each of these sub-matrices would get a unique straightforward. Each of these sub-matrices would get a unique
matrix identifier per [GEN-Encode]. matrix identifier per [GEN-Encode].
skipping to change at page 9, line 23 skipping to change at page 8, line 32
This document also introduces the following sub-TLVs of Generic Node This document also introduces the following sub-TLVs of Generic Node
Attribute TLV: Attribute TLV:
Type sub-TLV Type sub-TLV
TBD Connectivity Matrix TBD Connectivity Matrix
7.2. Link Information 7.2. Link Information
This document introduces the following sub-TLVs of TE Link TLV This document introduces the following sub-TLV of TE Link TLV (Value
(Value 2): 2):
Type sub-TLV Type sub-TLV
TBD Port Label Restrictions TBD Port Label Restrictions
TBD Available Labels
TBD Shared Backup Labels
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC5250] L. Berger, I. Bryskin, A. Zinin, R. Coltun "The OSPF [RFC5250] L. Berger, I. Bryskin, A. Zinin, R. Coltun "The OSPF
 End of changes. 22 change blocks. 
93 lines changed or deleted 43 lines changed or added

This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/