draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05.txt   rfc5145.txt 
Network Working Group K. Shiomoto(Editor)
Internet Draft (NTT)
Intended Status: Informational
Created: January 13, 2008
Expires: July 13, 2008
Framework for MPLS-TE to GMPLS migration
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05.txt
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Abstract Abstract
The migration from Multiprotocol Label Switching (MPLS) Traffic The migration from Multiprotocol Label Switching (MPLS) Traffic
Engineering (TE) to Generalized MPLS (GMPLS) is the process of Engineering (TE) to Generalized MPLS (GMPLS) is the process of
evolving an MPLS-TE control plane to a GMPLS control plane. An evolving an MPLS-TE control plane to a GMPLS control plane. An
appropriate migration strategy will be selected based on various appropriate migration strategy will be selected based on various
factors including the service provider's network deployment plan, factors including the service provider's network deployment plan,
customer demand, and operational policy. customer demand, and operational policy.
This document presents several migration models and strategies for This document presents several migration models and strategies for
migrating from MPLS-TE to GMPLS. In the course of migration, MPLS-TE migrating from MPLS-TE to GMPLS. In the course of migration, MPLS-TE
and GMPLS devices, or networks, may coexist which may require and GMPLS devices, or networks, may coexist that may require
interworking between MPLS-TE and GMPLS protocols. Aspects of the interworking between MPLS-TE and GMPLS protocols. Aspects of the
interworking required are discussed as it will influence the choice required interworking are discussed as it will influence the choice
of a migration strategy. This framework document provides a migration of a migration strategy. This framework document provides a
toolkit to aid the operator in selection of an appropriate strategy. migration toolkit to aid the operator in selection of an appropriate
strategy.
This framework document also lists a set of solutions that may aid in This framework document also lists a set of solutions that may aid in
interworking, and highlights a set of potential issues. interworking, and highlights a set of potential issues.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
Table of Contents Table of Contents
1. Introduction.................................................... 2 1. Introduction ....................................................3
2. Conventions Used in This Document............................... 3 2. Conventions Used in This Document............................... 3
3. Motivations for Migration....................................... 4 3. Motivations for Migration....................................... 4
4. MPLS to GMPLS Migration Models.................................. 4 4. MPLS to GMPLS Migration Models ..................................5
4.1. Island Model............................................... 5 4.1. Island Model............................................... 5
4.1.1. Balanced Islands...................................... 6 4.1.1. Balanced Islands ....................................6
4.1.2. Unbalanced Islands.................................... 6 4.1.2. Unbalanced Islands ..................................6
4.2. Integrated Model........................................... 7 4.2. Integrated Model........................................... 7
4.3. Phased Model............................................... 8 4.3. Phased Model............................................... 8
5. Migration Strategies and Toolkit................................ 8 5. Migration Strategies and Toolkit................................ 8
5.1. Migration Toolkit.......................................... 9 5.1. Migration Toolkit.......................................... 9
5.1.1. Layered Networks...................................... 9 5.1.1. Layered Networks ....................................9
5.1.2. Routing Interworking................................. 11 5.1.2. Routing Interworking ...............................11
5.1.3. Signaling Interworking............................... 12 5.1.3. Signaling Interworking .............................12
5.1.4. Path Computation Element............................. 13 5.1.4. Path Computation Element ...........................13
6. Manageability Considerations................................... 13 6. Manageability Considerations................................... 13
6.1. Control of Function and Policy............................ 13 6.1. Control of Function and Policy............................ 13
6.2. Information and Data Models............................... 14 6.2. Information and Data Models............................... 14
6.3. Liveness Detection and Monitoring......................... 14 6.3. Liveness Detection and Monitoring......................... 14
6.4. Verifying Correct Operation............................... 14 6.4. Verifying Correct Operation............................... 14
6.5. Requirements on Other Protocols and Functional Components. 14 6.5. Requirements on Other Protocols and Functional
Components ................................................14
6.6. Impact on Network Operation............................... 15 6.6. Impact on Network Operation............................... 15
6.7. Other Considerations...................................... 15 6.7. Other Considerations...................................... 15
7. Security Considerations........................................ 15 7. Security Considerations........................................ 15
8. IANA Considerations............................................ 16 8. Acknowledgements ...............................................16
9. Acknowledgements............................................... 16 9. References .....................................................16
10. Editor's Addresses............................................ 16 9.1. Normative References ......................................16
11. Authors' Addresses............................................ 16 9.2. Informative References ....................................17
12. References.................................................... 17 10. Contributors' Addresses .......................................17
12.1. Normative References..................................... 17
12.2. Informative References................................... 18
13. Full Copyright Statement...................................... 19
14. Intellectual Property......................................... 19
1. Introduction 1. Introduction
Multiprotocol Label Switching Traffic Engineering (MPLS-TE) to Multiprotocol Label Switching Traffic Engineering (MPLS-TE) to
Generalized MPLS (GMPLS) migration is the process of evolving an Generalized MPLS (GMPLS) migration is the process of evolving an
MPLS-TE-based control plane to a GMPLS-based control plane. The MPLS-TE-based control plane to a GMPLS-based control plane. The
network under consideration for migration is, therefore, a packet- network under consideration for migration is, therefore, a
switching network. packet-switching network.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
There are several motivations for such migration, mainly the desire There are several motivations for such migration, mainly the desire
to take advantage of new features and functions added to the GMPLS to take advantage of new features and functions added to the GMPLS
protocols and which are not present in MPLS-TE for packet networks. protocols, which are not present in MPLS-TE for packet networks.
Additionally, before migrating a packet-switching network from MPLS- Additionally, before migrating a packet-switching network from
TE to GMPLS, one may choose to first migrate a lower-layer network MPLS-TE to GMPLS, one may choose to first migrate a lower-layer
with no control plane (e.g. controlled by a management plane) to network with no control plane (e.g., controlled by a management
using a GMPLS control plane, and this may lead to the desire for plane) to using a GMPLS control plane. This may lead to the desire
MPLS-TE/GMPLS (transport network) interworking to provide enhanced TE for MPLS-TE/GMPLS (transport network) interworking to provide
support and facilitate the later migration of the packet-switching enhanced TE support and facilitate the later migration of the
network. packet-switching network.
Although an appropriate migration strategy will be selected based on Although an appropriate migration strategy will be selected based on
various factors including the service provider's network deployment various factors including the service provider's network deployment
plan, customer demand, deployed network equipments, operational plan, customer demand, deployed network equipments, operational
policy, etc., the transition mechanisms used should also provide policy, etc., the transition mechanisms used should also provide
consistent operation of newly introduced GMPLS networks, while consistent operation of newly introduced GMPLS networks, while
minimizing the impact on the operation of existing MPLS-TE networks. minimizing the impact on the operation of existing MPLS-TE networks.
This document describes several migration strategies and the This document describes several migration strategies and the
interworking scenarios that arise during migration. It also examines interworking scenarios that arise during migration. It also examines
the implications for network deployments and for protocol usage. As the implications for network deployments and for protocol usage. As
the GMPLS signaling and routing protocols are different from the the GMPLS signaling and routing protocols are different from the
MPLS-TE control protocols, interworking mechanisms between MPLS-TE MPLS-TE control protocols, interworking mechanisms between MPLS-TE
and GMPLS networks, or network elements, may be needed to compensate and GMPLS networks, or network elements, may be needed to compensate
for the differences. for the differences.
Note that MPLS-TE and GMPLS protocols can co-exist as "ships in the Note that MPLS-TE and GMPLS protocols can coexist as "ships in the
night" without any interworking issue. night" without any interworking issues.
2. Conventions Used in This Document 2. Conventions Used in This Document
This is not a requirements document, nevertheless the key words This is not a requirements document, nevertheless the key words
"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
"SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document
are to be interpreted as described in RFC 2119 [RFC2119] in order to are to be interpreted as described in RFC 2119 [RFC2119] in order to
clarify the recommendations that are made. clarify the recommendations that are made.
In the rest of this document, the term "GMPLS" includes both packet In the rest of this document, the term "GMPLS" includes both packet
switching capable (PSC) and non-PSC. Otherwise the term "PSC GMPLS" switching capable (PSC) and non-PSC. Otherwise, the term "PSC GMPLS"
or "non-PSC GMPLS" is explicitly used. or "non-PSC GMPLS" is used explicitly.
In general, the term "MPLS" is used to indicate MPLS traffic In general, the term "MPLS" is used to indicate MPLS traffic
engineering (MPLS-TE) only ([RFC3209], [RFC3630], [RFC3784]) and engineering (MPLS-TE) only ([RFC3209], [RFC3630], and [RFC3784]) and
excludes other MPLS protocols such as the Label Distribution Protocol excludes other MPLS protocols, such as the Label Distribution
(LDP). TE functionalities of MPLS could be migrated to GMPLS, but Protocol (LDP). TE functionalities of MPLS could be migrated to
non-TE functionalities could not. If non-TE MPLS is intended, it is GMPLS, but non-TE functionalities could not. If non-TE MPLS is
explicitly indicated. intended, it is indicated explicitly.
The reader is assumed to be familiar with the terminology introduced The reader is assumed to be familiar with the terminology introduced
in [RFC3945]. in [RFC3945].
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
3. Motivations for Migration 3. Motivations for Migration
Motivations for migration will vary for different service providers. Motivations for migration will vary for different service providers.
This section is presented to provide background so that the migration This section is presented to provide background so that the migration
discussions may be seen in context. Sections 4 and 5 provide examples discussions may be seen in context. Sections 4 and 5 provide
to illustrate the migration models and processes. examples to illustrate the migration models and processes.
Migration of an MPLS-capable LSR to include GMPLS capabilities may be Migration of an MPLS-capable Label Switching Router (LSR) to include
performed for one or more reasons, including, not exhaustively: GMPLS capabilities may be performed for one or more reasons,
including, not exhaustively:
o To add all GMPLS PSC features to an existing MPLS network (upgrade o To add all GMPLS PSC features to an existing MPLS network (upgrade
MPLS LSRs). MPLS LSRs).
o To add specific GMPLS PSC features and operate them within an MPLS o To add specific GMPLS PSC features and operate them within an MPLS
network (ex. [RFC4872] [RFC4873]). network (e.g., [RFC4872] and [RFC4873]).
o To integrate a new GMPLS PSC network with an existing MPLS network o To integrate a new GMPLS PSC network with an existing MPLS network
(without upgrading any of the MPLS LSRs). (without upgrading any of the MPLS LSRs).
o To allow existing MPLS LSRs to interoperate with new non-MPLS LSRs o To allow existing MPLS LSRs to interoperate with new non-MPLS LSRs
supporting only GMPLS PSC and/or non-PSC features. supporting only GMPLS PSC and/or non-PSC features.
o To integrate multiple control networks, e.g. managed by separate o To integrate multiple control networks, e.g., managed by separate
administrative organizations, and which independently utilize MPLS administrative organizations, and which independently utilize MPLS
or GMPLS. or GMPLS.
o To build integrated PSC and non-PSC networks. The non-PSC networks o To build integrated PSC and non-PSC networks. The non-PSC
are controlled by GMPLS. networks are controlled by GMPLS.
The objective of migration from MPLS to GMPLS is that all LSRs, and The objective of migration from MPLS to GMPLS is that all LSRs, and
the entire network, support GMPLS protocols. During this process, the entire network, support GMPLS protocols. During this process,
various interim situations may exist, giving rise to the interworking various interim situations may exist, giving rise to the interworking
situations described in this document. The interim situations may situations described in this document. The interim situations may
exist for considerable periods of time, but the ultimate objective is exist for considerable periods of time, but the ultimate objective is
not to preserve these situations. For the purposes of this document, not to preserve these situations. For the purposes of this document,
they should be considered as temporary and transitory. they should be considered as temporary and transitory.
4. MPLS to GMPLS Migration Models 4. MPLS to GMPLS Migration Models
Three reference migration models are described below. Multiple Three reference migration models are described below. Multiple
migration models may co-exist in the same network. migration models may coexist in the same network.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
4.1. Island Model 4.1. Island Model
In the island model, "islands" of network nodes operating one In the island model, "islands" of network nodes operating one
protocol exist within a "sea" of nodes using the other protocol. protocol exist within a "sea" of nodes using the other protocol.
For example, consider an island of GMPLS-capable nodes (PSC) which is For example, consider an island of GMPLS-capable nodes (PSC) that is
introduced into a legacy MPLS network. Such an island might be introduced into a legacy MPLS network. Such an island might be
composed of newly added GMPLS nodes, or might arise from the upgrade composed of newly added GMPLS nodes, or it might arise from the
of existing nodes that previously operated MPLS protocols. upgrade of existing nodes that previously operated MPLS protocols.
The opposite is also quite possible. That is, there is a possibility The opposite is also quite possible. That is, there is a possibility
that an island happens to be MPLS-capable within a GMPLS sea. Such a that an island happens to be MPLS-capable within a GMPLS sea. Such a
situation might arise in the later stages of migration, when all but situation might arise in the later stages of migration, when all but
a few islands of MPLS-capable nodes have been upgraded to GMPLS. a few islands of MPLS-capable nodes have been upgraded to GMPLS.
It is also possible that a lower-layer, manually-provisioned network It is also possible that a lower-layer, manually-provisioned network
(for example, a TDM network) is constructed under an MPLS PSC (for example, a Time Division Multiplexing (TDM) network) is
network. During the process of migrating both networks to GMPLS, the constructed under an MPLS PSC network. During the process of
lower-layer network might be migrated first. This would appear as a migrating both networks to GMPLS, the lower-layer network might be
GMPLS island within an MPLS sea. migrated first. This would appear as a GMPLS island within an MPLS
sea.
Lastly, it is possible to consider individual nodes as islands. That Lastly, it is possible to consider individual nodes as islands. That
is, it would be possible to upgrade or insert an individual GMPLS- is, it would be possible to upgrade or insert an individual
capable node within an MPLS network, and to treat that GMPLS node as GMPLS-capable node within an MPLS network, and to treat that GMPLS
an island. node as an island.
Over time, collections of MPLS devices are replaced or upgraded to Over time, collections of MPLS devices are replaced or upgraded to
create new GMPLS islands or to extend existing ones, and distinct create new GMPLS islands or to extend existing ones, and distinct
GMPLS islands may be joined together until the whole network is GMPLS islands may be joined together until the whole network is
GMPLS-capable. GMPLS-capable.
From a migration/interworking point of view, we need to examine how From a migration/interworking point of view, we need to examine how
these islands are positioned and how LSPs connect between the these islands are positioned and how Label Switched Paths (LSPs)
islands. connect between the islands.
Four categories of interworking scenarios are considered: (1) MPLS- Four categories of interworking scenarios are considered: (1)
GMPLS-MPLS, (2) GMPLS-MPLS-GMPLS, (3) MPLS-GMPLS and (4) GMPLS-MPLS. MPLS-GMPLS-MPLS, (2) GMPLS-MPLS-GMPLS, (3) MPLS-GMPLS, and (4)
In case 1, the interworking behavior is examined based on whether the GMPLS-MPLS. In case 1, the interworking behavior is examined based
GMPLS islands are PSC or non-PSC. on whether the GMPLS islands are PSC or non-PSC.
Figure 1 shows an example of the island model for MPLS-GMPLS-MPLS Figure 1 shows an example of the island model for MPLS-GMPLS-MPLS
interworking. The model consists of a transit GMPLS island in an MPLS interworking. The model consists of a transit GMPLS island in an
sea. The nodes at the boundary of the GMPLS island (G1, G2, G5, and MPLS sea. The nodes at the boundary of the GMPLS island (G1, G2, G5,
G6) are referred to as "island border nodes". If the GMPLS island was and G6) are referred to as "island border nodes". If the GMPLS
non-PSC, all nodes except the island border nodes in the GMPLS-based island was non-PSC, all nodes except the island border nodes in the
transit island (G3 and G4) would be non-PSC devices, i.e., optical GMPLS-based transit island (G3 and G4) would be non-PSC devices,
equipment (TDM, LSC, and FSC). i.e., optical equipment (TDM, Lambda Switch Capable (LSC), and Fiber
Switch Capable (FSC)).
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
................. .......................... .................. ................. .......................... ..................
: MPLS : : GMPLS : : MPLS : : MPLS : : GMPLS : : MPLS :
:+---+ +---+ +----+ +---+ +----+ +---+ +---+: :+---+ +---+ +----+ +---+ +----+ +---+ +---+:
:|R1 |__|R11|___| G1 |_________|G3 |________| G5 |___|R31|__|R3 |: :|R1 |__|R11|___| G1 |_________|G3 |________| G5 |___|R31|__|R3 |:
:+---+ +---+ +----+ +-+-+ +----+ +---+ +---+: :+---+ +---+ +----+ +-+-+ +----+ +---+ +---+:
: ________/ : : _______/ | _____ / : : ________/ : : ________/ : : _______/ | _____ / : : ________/ :
: / : : / | / : : / : : / : : / | / : : / :
:+---+ +---+ +----+ +-+-+ +----+ +---+ +---+: :+---+ +---+ +----+ +-+-+ +----+ +---+ +---+:
:|R2 |__|R21|___| G2 |_________|G4 |________| G6 |___|R41|__|R4 |: :|R2 |__|R21|___| G2 |_________|G4 |________| G6 |___|R41|__|R4 |:
:+---+ +---+ +----+ +---+ +----+ +---+ +---+: :+---+ +---+ +----+ +---+ +----+ +---+ +---+:
:................: :........................: :................: :................: :........................: :................:
|<-------------------------------------------------------->| |<-------------------------------------------------------->|
e2e LSP e2e LSP
Figure 1 : Example of the island model for Figure 1: Example of the island model
MPLS-GMPLS-MPLS interworking. for MPLS-GMPLS-MPLS interworking
4.1.1. Balanced Islands 4.1.1. Balanced Islands
In the MPLS-GMPLS-MPLS and GMPLS-MPLS-GMPLS cases, LSPs start and end In the MPLS-GMPLS-MPLS and GMPLS-MPLS-GMPLS cases, LSPs start and end
using the same protocols. Possible strategies include: using the same protocols. Possible strategies include:
- tunneling the signaling across the island network using LSP - tunneling the signaling across the island network using LSP nesting
nesting or stitching [STITCH] (the latter is for only with GMPLS- or stitching [RFC5150] (the latter is only for GMPLS-PSC)
PSC)
- protocol interworking or mapping (both are for only with GMPLS- - protocol interworking or mapping (both are only for GMPLS-PSC)
PSC)
4.1.2. Unbalanced Islands 4.1.2. Unbalanced Islands
As previously discussed, there are two island interworking models As previously discussed, there are two island interworking models
which support bordering islands. GMPLS(PSC)-MPLS and MPLS-GMPLS(PSC) that support bordering islands. GMPLS(PSC)-MPLS and MPLS-GMPLS(PSC)
island cases are likely to arise where the migration strategy is not island cases are likely to arise where the migration strategy is not
based on a core infrastructure, but has edge nodes (ingress or based on a core infrastructure, but has edge nodes (ingress or
egress) located in islands of different capabilities. egress) located in islands of different capabilities.
In this case, an LSP starts or ends in a GMPLS (PSC) island and In this case, an LSP starts or ends in a GMPLS (PSC) island and
correspondingly ends or starts in an MPLS island. This mode of correspondingly ends or starts in an MPLS island. This mode of
operation can only be addressed using protocol interworking or operation can only be addressed using protocol interworking or
mapping. Figure 2 shows the reference model for this migration mapping. Figure 2 shows the reference model for this migration
scenario. Head-end and tail-end LSR are in distinct control plane scenario. Head-end and tail-end LSRs are in distinct control plane
clouds. clouds.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
............................ ............................. ............................ .............................
: MPLS : : GMPLS (PSC) : : MPLS : : GMPLS (PSC) :
:+---+ +---+ +----+ +---+ +---+: :+---+ +---+ +----+ +---+ +---+:
:|R1 |________|R11|_______| G1 |________|G3 |________|G5 |: :|R1 |________|R11|_______| G1 |________|G3 |________|G5 |:
:+---+ +---+ +----+ +-+-+ +---+: :+---+ +---+ +----+ +-+-+ +---+:
: ______/ | _____/ : : ______/ | ______/ : : ______/ | _____/ : : ______/ | ______/ :
: / | / : : / | / : : / | / : : / | / :
:+---+ +---+ +----+ +-+-+ +---+: :+---+ +---+ +----+ +-+-+ +---+:
:|R2 |________|R21|_______| G2 |________|G4 |________|G6 |: :|R2 |________|R21|_______| G2 |________|G4 |________|G6 |:
:+---+ +---+ +----+ +---+ +---+: :+---+ +---+ +----+ +---+ +---+:
:..........................: :...........................: :..........................: :...........................:
|<-------------------------------------------------->| |<-------------------------------------------------->|
e2e LSP e2e LSP
Figure 2 : GMPLS-MPLS interworking model. Figure 2: GMPLS-MPLS interworking model
It is important to underline that this scenario is also impacted by It is important to underline that this scenario is also impacted by
the directionality of the LSP, and the direction in which the LSP is the directionality of the LSP, and the direction in which the LSP is
established. established.
4.2. Integrated Model 4.2. Integrated Model
The second migration model involves a more integrated migration The second migration model involves a more integrated migration
strategy. New devices that are capable of operating both MPLS and strategy. New devices that are capable of operating both MPLS and
GMPLS protocols are introduced into the MPLS network. GMPLS protocols are introduced into the MPLS network.
In the integrated model there are two types of nodes present during In the integrated model, there are two types of nodes present during
migration: migration:
- support MPLS only (legacy nodes) - those that support MPLS only (legacy nodes); and
- support MPLS and GMPLS. - those that support MPLS and GMPLS.
In this model, as existing MPLS devices are upgraded to support both In this model, as existing MPLS devices are upgraded to support both
MPLS and GMPLS, the network continues to operate with a MPLS control MPLS and GMPLS, the network continues to operate with an MPLS control
plane, but some LSRs are also capable of operating with a GMPLS plane, but some LSRs are also capable of operating with a GMPLS
control plane. So, LSPs are provisioned using MPLS protocols where control plane. So, LSPs are provisioned using MPLS protocols where
one end point of a service is a legacy MPLS node and/or where the one end point of a service is a legacy MPLS node and/or where the
selected path between end points traverses a legacy node that is not selected path between end points traverses a legacy node that is not
GMPLS-capable. But where the service can be provided using only GMPLS-capable. But where the service can be provided using only
GMPLS-capable nodes [RFC5073], it may be routed accordingly and can GMPLS-capable nodes [RFC5073], it may be routed accordingly and can
achieve a higher level of functionality by utilizing GMPLS features. achieve a higher level of functionality by utilizing GMPLS features.
Once all devices in the network are GMPLS-capable, the MPLS specific Once all devices in the network are GMPLS-capable, the MPLS-specific
protocol elements may be turned off, and no new devices need to protocol elements may be turned off, and no new devices need to
support these protocol elements. support these protocol elements.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008 In this model, the questions to be addressed concern the coexistence
In this model, the questions to be addressed concern the co-existence
of the two protocol sets within the network. Actual interworking is of the two protocol sets within the network. Actual interworking is
not a concern. not a concern.
4.3. Phased Model 4.3. Phased Model
The phased model introduces GMPLS features and protocol elements into The phased model introduces GMPLS features and protocol elements into
an MPLS network one by one. For example, some objects or sub-objects an MPLS network one by one. For example, some objects or sub-objects
(such as the ERO label sub-object, [RFC3473]) might be introduced (such as the Explicit Route Object (ERO) label sub-object, [RFC3473])
into the signaling used by LSRs that are otherwise MPLS-capable. This might be introduced into the signaling used by LSRs that are
would produce a kind of hybrid LSR. otherwise MPLS-capable. This would produce a kind of hybrid LSR.
This approach may appear simpler to implement as one is able to This approach may appear simpler to implement as one is able to
quickly and easily pick up key new functions without needing to quickly and easily pick up new key functions without needing to
upgrade the whole protocol implementation. It is most likely to be upgrade the whole protocol implementation. It is most likely to be
used where there is a desire to rapidly implement a particular used where there is a desire to rapidly implement a particular
function within a network without the necessity to install and test function within a network without the necessity to install and test
the full GMPLS function. the full GMPLS function.
Interoperability concerns though are exacerbated by this migration Interoperability concerns though are exacerbated by this migration
model, unless all LSRs in the network are updated simultaneously and model, unless all LSRs in the network are updated simultaneously and
there is a clear understanding of which subset of features are to be there is a clear understanding of which subset of features are to be
included in the hybrid LSRs. Interworking between a hybrid LSR and an included in the hybrid LSRs. Interworking between a hybrid LSR and
unchanged MPLS LSR would put the hybrid LSR in the role of a GMPLS an unchanged MPLS LSR would put the hybrid LSR in the role of a GMPLS
LSR as described in the previous sections and puts the unchanged LSR LSR, as described in the previous sections, and puts the unchanged
in the role of an MPLS LSR. The potential for different hybrids LSR in the role of an MPLS LSR. The potential for different hybrids
within the network will complicate matters considerably. This model within the network will complicate matters considerably. This model
is, therefore, only appropriate for use when the set of new features is, therefore, only appropriate for use when the set of new features
to be deployed is well known and limited, and where there is a clear to be deployed is well known and limited, and where there is a clear
understanding of and agreement on this set of features by the network understanding of and agreement on this set of features by the network
operators of the ISP(s) involved as well as all vendors whose operators of the ISP(s) involved as well as all vendors whose
equipment will be involved in the migration. equipment will be involved in the migration.
5. Migration Strategies and Toolkit 5. Migration Strategies and Toolkit
An appropriate migration strategy is selected by a network operator An appropriate migration strategy is selected by a network operator
based on factors including the service provider's network deployment based on factors including the service provider's network deployment
plan, customer demand, existing network equipment, operational plan, customer demand, existing network equipment, operational
policy, support from its vendors, etc. policy, support from its vendors, etc.
For PSC networks, the migration strategy involves the selection For PSC networks, the migration strategy involves the selection
between the models described in the previous section. The choice will between the models described in the previous section. The choice
depend upon the final objective (full GMPLS capability, partial will depend upon the final objective (full GMPLS capability, partial
upgrade to include specific GMPLS features, or no change to existing upgrade to include specific GMPLS features, or no change to existing
IP/MPLS networks), and upon the immediate objectives (full, phased, IP/MPLS networks), and upon the immediate objectives (full, phased,
or staged upgrade). or staged upgrade).
For PSC networks serviced by non-PSC networks, two basic migration For PSC networks serviced by non-PSC networks, two basic migration
strategies can be considered. In the first strategy, the non-PSC strategies can be considered. In the first strategy, the non-PSC
network is made GMPLS-capable, first, and then the PSC network is network is made GMPLS-capable, first, and then the PSC network is
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
migrated to GMPLS. This might arise when, in order to expand the migrated to GMPLS. This might arise when, in order to expand the
network capacity, GMPLS-based non-PSC sub-networks are introduced network capacity, GMPLS-based non-PSC sub-networks are introduced
into the legacy MPLS-based networks. Subsequently, the legacy MPLS- into the legacy MPLS-based networks. Subsequently, the legacy
based PSC network is migrated to be GMPLS-capable as described in the MPLS-based PSC network is migrated to be GMPLS-capable, as described
previous paragraph. Finally the entire network, including both PSC in the previous paragraph. Finally, the entire network, including
and non-PSC nodes, may be controlled by GMPLS. both PSC and non-PSC nodes, may be controlled by GMPLS.
The second strategy is to migrate the PSC network to GMPLS first, and The second strategy is to migrate the PSC network to GMPLS first, and
then enable GMPLS within the non-PSC network. The PSC network is then enable GMPLS within the non-PSC network. The PSC network is
migrated as described before, and when the entire PSC network is migrated as described before, and when the entire PSC network is
completely converted to GMPLS, GMPLS-based non-PSC devices and completely converted to GMPLS, GMPLS-based non-PSC devices and
networks may be introduced without any issues of interworking between networks may be introduced without any issues of interworking between
MPLS and GMPLS. MPLS and GMPLS.
These migration strategies and the migration models described in the These migration strategies and the migration models described in the
previous section are not necessarily mutually exclusive. Mixtures of previous section are not necessarily mutually exclusive. Mixtures of
all strategies and models could be applied. The migration models and all strategies and models could be applied. The migration models and
strategies selected will give rise to one or more of the interworking strategies selected will give rise to one or more of the interworking
cases described in the following section. cases described in the following section.
5.1. Migration Toolkit 5.1. Migration Toolkit
As described in the previous sections, an essential part of a As described in the previous sections, an essential part of a
migration and deployment strategy is how the MPLS and GMPLS or hybrid migration and deployment strategy is how the MPLS and GMPLS or hybrid
LSRs interwork. This section sets out some of the alternatives for LSRs interwork. This section sets out some of the alternatives for
achieving interworking between MPLS and GMPLS, and identifies some of achieving interworking between MPLS and GMPLS, and it identifies some
the issues that need to be addressed. This document does not describe of the issues that need to be addressed. This document does not
solutions to these issues. describe solutions to these issues.
Note that it is possible to consider upgrading the routing and Note that it is possible to consider upgrading the routing and
signaling capabilities of LSRs from MPLS to GMPLS separately. signaling capabilities of LSRs from MPLS to GMPLS separately.
5.1.1. Layered Networks 5.1.1. Layered Networks
In the balanced island model, LSP tunnels [RFC4206] are a solution to In the balanced island model, LSP tunnels [RFC4206] are a solution to
carry the end-to-end LSPs across islands of incompatible nodes. carry the end-to-end LSPs across islands of incompatible nodes.
Network layering is often used to separate domains of different data Network layering is often used to separate domains of different data
plane technology. It can also be used to separate domains of plane technology. It can also be used to separate domains of
different control plane technology (such as MPLS and GMPLS different control plane technology (such as MPLS and GMPLS
protocols), and the solutions developed for multiple data plane protocols), and the solutions developed for multiple data plane
technologies can be usefully applied to this situation [RFC3945], technologies can be usefully applied to this situation [RFC3945],
[RFC4206], and [RFC4726]. [MLN-REQ] gives a discussion of the [RFC4206], and [RFC4726]. [MLN-REQ] gives a discussion of the
requirements for multi-layered networks. requirements for multi-layered networks.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
The GMPLS architecture [RFC3945] identifies three architectural The GMPLS architecture [RFC3945] identifies three architectural
models for supporting multi-layer GMPLS networks, and these models models for supporting multi-layer GMPLS networks, and these models
may be applied to the separation of MPLS and GMPLS control plane may be applied to the separation of MPLS and GMPLS control plane
islands. islands.
- In the peer model, both MPLS and GMPLS nodes run the same routing - In the peer model, both MPLS and GMPLS nodes run the same routing
instance, and routing advertisements from within islands of one instance, and routing advertisements from within islands of one
level of protocol support are distributed to the whole network. level of protocol support are distributed to the whole network.
This is achievable only as described in section 5.1.2 either by This is achievable only, as described in Section 5.1.2, either by
direct distribution or by mapping of parameters. direct distribution or by mapping of parameters.
Signaling in the peer model may result in contiguous LSPs, Signaling in the peer model may result in contiguous LSPs, stitched
stitched LSPs [STITCH] (only for GMPLS PSC), or nested LSPs. If LSPs [RFC5150] (only for GMPLS PSC), or nested LSPs. If the
the network islands are non-PSC then the techniques of [MLN-REQ] network islands are non-PSC, then the techniques of [MLN-REQ] may
may be applied, and these techniques may be extrapolated to be applied, and these techniques may be extrapolated to networks
networks where all nodes are PSC, but where there is a difference where all nodes are PSC, but where there is a difference in
in signaling protocols. signaling protocols.
- The overlay model preserves strict separation of routing - The overlay model preserves strict separation of routing
information between network layers. This is suitable for the information between network layers. This is suitable for the
balanced island model and there is no requirement to handle balanced island model, and there is no requirement to handle
routing interworking. Even though the overlay model preserves routing interworking. Even though the overlay model preserves
separation of signaling information between network layers, there separation of signaling information between network layers, there
may be some interaction in signaling between network layers. may be some interaction in signaling between network layers.
The overlay model requires the establishment of control plane The overlay model requires the establishment of control plane
connectivity for the higher layer across the lower layer. connectivity for the higher layer across the lower layer.
- The augmented model allows limited routing exchange from the lower - The augmented model allows limited routing exchange from the
layer network to the higher layer network. Generally speaking, lower-layer network to the higher-layer network. Generally
this assumes that the border nodes provide some form of filtering, speaking, this assumes that the border nodes provide some form of
mapping or aggregation of routing information advertised from the filtering, mapping, or aggregation of routing information
lower layer network. This architectural model can also be used for advertised from the lower-layer network. This architectural model
balanced island model migrations. Signaling interworking is can also be used for balanced island model migrations. Signaling
required as described for the peer model. interworking is required as described for the peer model.
- The border peer architecture model is defined in [MPLS-OVER-GMPLS]. - The border peer architecture model is defined in [RFC5146]. This
This is a modification of the augmented model where the layer is a modification of the augmented model where the layer border
border routers have visibility into both layers, but no routing routers have visibility into both layers, but no routing
information is otherwise exchanged between routing protocol information is otherwise exchanged between routing protocol
instances. This architectural model is particularly suited to the instances. This architectural model is particularly suited to the
MPLS-GMPLS-MPLS island model for PSC and non-PSC GMPLS islands. MPLS-GMPLS-MPLS island model for PSC and non-PSC GMPLS islands.
Signaling interworking is required as described for the peer model. Signaling interworking is required as described for the peer model.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
5.1.2. Routing Interworking 5.1.2. Routing Interworking
Migration strategies may necessitate some interworking between MPLS Migration strategies may necessitate some interworking between MPLS
and GMPLS routing protocols. GMPLS extends the TE information and GMPLS routing protocols. GMPLS extends the TE information
advertised by the IGPs to include non-PSC information and extended advertised by the IGPs to include non-PSC information and extended
PSC information. Because the GMPLS information is provided as PSC information. Because the GMPLS information is provided as
additional TLVs that are carried along with the MPLS information, additional TLVs that are carried along with the MPLS information,
MPLS LSRs are able to "see" all GMPLS LSRs as though they were MPLS MPLS LSRs are able to "see" all GMPLS LSRs as though they were MPLS
PSC LSRs. They will also see other GMPLS information, but will ignore PSC LSRs. They will also see other GMPLS information, but will
it, flooding it transparently across the MPLS network for use by ignore it, flooding it transparently across the MPLS network for use
other GMPLS LSRs. by other GMPLS LSRs.
- Routing separation is achieved in the overlay and border peer - Routing separation is achieved in the overlay and border peer
models. This is convenient since only the border nodes need to be models. This is convenient since only the border nodes need to be
aware of the different protocol variants, and no mapping is aware of the different protocol variants, and no mapping is
required. It is suitable to the MPLS-GMPLS-MPLS and GMPLS-MPLS- required. It is suitable to the MPLS-GMPLS-MPLS and
GMPLS island migration models. GMPLS-MPLS-GMPLS island migration models.
- Direct distribution involves the flooding of MPLS routing - Direct distribution involves the flooding of MPLS routing
information into a GMPLS network, and GMPLS routing information information into a GMPLS network, and GMPLS routing information
into an MPLS network. The border nodes make no attempt to filter into an MPLS network. The border nodes make no attempt to filter
the information. This mode of operation relies on the fact that the information. This mode of operation relies on the fact that
MPLS routers will ignore, but continue to flood, GMPLS routing MPLS routers will ignore, but continue to flood, GMPLS routing
information that they do not understand. The presence of information that they do not understand. The presence of
additional GMPLS routing information will not interfere with the additional GMPLS routing information will not interfere with the
way that MPLS LSRs select routes, and although this is not a way that MPLS LSRs select routes. Although this is not a problem
problem in a PSC-only network, it could cause problems in a peer in a PSC-only network, it could cause problems in a peer
architecture network that includes non-PSC nodes as the MPLS nodes architecture network that includes non-PSC nodes, as the MPLS nodes
are not capable of determining the switching types of the other are not capable of determining the switching types of the other
LSRs and will attempt to signal end-to-end LSPs assuming all LSRs LSRs and will attempt to signal end-to-end LSPs assuming all LSRs
to be PSC. This fact would require island border nodes to take to be PSC. This fact would require island border nodes to take
triggered action to set up tunnels across islands of different triggered action to set up tunnels across islands of different
switching capabilities. switching capabilities.
GMPLS LSRs might be impacted by the absence of GMPLS-specific GMPLS LSRs might be impacted by the absence of GMPLS-specific
information in advertisements initiated by MPLS LSRs. Specific information in advertisements initiated by MPLS LSRs. Specific
procedures might be required to ensure consistent behavior by procedures might be required to ensure consistent behavior by GMPLS
GMPLS nodes. If this issue is addressed, then direct distribution nodes. If this issue is addressed, then direct distribution can be
can be used in all migration models (except the overlay and border used in all migration models (except the overlay and border peer
peer architectural models where the problem does not arise). architectural models where the problem does not arise).
- Protocol mapping converts routing advertisements so that they can - Protocol mapping converts routing advertisements so that they can
be received in one protocol and transmitted in the other. For be received in one protocol and transmitted in the other. For
example, a GMPLS routing advertisement could have all of its example, a GMPLS routing advertisement could have all of its
GMPLS-specific information removed and could be flooded as an MPLS GMPLS-specific information removed and could be flooded as an MPLS
advertisement. This mode of interworking would require careful advertisement. This mode of interworking would require careful
standardization of the correct behavior especially where an MPLS standardization of the correct behavior especially where an MPLS
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
advertisement requires default values of GMPLS-specific fields to advertisement requires default values of GMPLS-specific fields to
be generated before the advertisement can be flooded further. be generated before the advertisement can be flooded further.
There is also considerable risk of confusion in closely meshed There is also considerable risk of confusion in closely meshed
networks where many LSRs have MPLS and GMPLS capable interfaces. networks where many LSRs have MPLS- and GMPLS-capable interfaces.
This option for routing interworking during migration is NOT This option for routing interworking during migration is NOT
RECOMMENDED for any migration model. Note that converting GMPLS- RECOMMENDED for any migration model. Note that converting
specific sub-TLVs to MPLS-specific ones but not stripping the GMPLS-specific sub-TLVs to MPLS-specific ones but not stripping the
GMPLS-specific ones is considered as a variant of the proposed GMPLS-specific ones is considered a variant of the proposed
solution in the previous bullet (Unknown sub-TLVs should be solution in the previous bullet (unknown sub-TLVs should be ignored
ignored [RFC3630] but must continue to be flooded). [RFC3630] but must continue to be flooded).
- Ships in the night refers to a mode of operation where both MPLS - Ships in the night refers to a mode of operation where both MPLS
and GMPLS routing protocol variants are operated in the same and GMPLS routing protocol variants are operated in the same
network at the same time as separate routing protocol instances. network at the same time as separate routing protocol instances.
The two instances are independent and are used to create routing The two instances are independent and are used to create routing
adjacencies between LSRs of the same type. This mode of operation adjacencies between LSRs of the same type. This mode of operation
may be appropriate to the integrated migration model. may be appropriate to the integrated migration model.
5.1.3. Signaling Interworking 5.1.3. Signaling Interworking
Signaling protocols are used to establish LSPs and are the principal Signaling protocols are used to establish LSPs and are the principal
concern for interworking during migration. Issues of compatibility concern for interworking during migration. Issues of compatibility
arise because of differences in the encodings and codepoints used by arise because of differences in the encodings and codepoints used by
MPLS and GMPLS signaling, but also because of differences in MPLS and GMPLS signaling, but also because of differences in
functionality provided by MPLS and GMPLS. functionality provided by MPLS and GMPLS.
- Tunneling and stitching [STITCH] (GMPLS-PSC case) mechanisms - Tunneling and stitching [RFC5150] (GMPLS-PSC case) mechanisms
provide the potential to avoid direct protocol interworking during provide the potential to avoid direct protocol interworking during
migration in the island model, because protocol elements are migration in the island model because protocol elements are
transported transparently across migration islands without being transported transparently across migration islands without being
inspected. However, care may be needed to achieve functional inspected. However, care may be needed to achieve functional
mapping in these modes of operation since one set of features may mapping in these modes of operation since one set of features may
need to be supported across a network designed to support a need to be supported across a network designed to support a
different set of features. In general, this is easily achieved for different set of features. In general, this is easily achieved for
the MPLS-GMPLS-MPLS model, but may be hard to achieve in the the MPLS-GMPLS-MPLS model, but may be hard to achieve in the
GMPLS-MPLS-GMPLS model. For example, when end-to-end bidirectional GMPLS-MPLS-GMPLS model, for example, when end-to-end bidirectional
LSPs are requested, since the MPLS island does not support LSPs are requested, since the MPLS island does not support
bidirectional LSPs. bidirectional LSPs.
Note that tunneling and stitching are not available in unbalanced Note that tunneling and stitching are not available in unbalanced
island models because in these cases the LSP end points use island models because in these cases, the LSP end points use
different protocols. different protocols.
- Protocol mapping is the conversion of signaling messages between - Protocol mapping is the conversion of signaling messages between
MPLS and GMPLS. This mechanism requires careful documentation of MPLS and GMPLS. This mechanism requires careful documentation of
the protocol fields and how they are mapped. This is relatively the protocol fields and how they are mapped. This is relatively
straightforward in the MPLS-GMPLS unbalanced island model for LSPs straightforward in the MPLS-GMPLS unbalanced island model for LSPs
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
signaled in the MPLS-GMPLS direction. However, it may be more signaled in the MPLS-GMPLS direction. However, it may be more
complex for LSPs signaled in the opposite direction, and this will complex for LSPs signaled in the opposite direction, and this will
lead to considerable complications for providing GMPLS services lead to considerable complications for providing GMPLS services
over the MPLS island and for terminating those services at an over the MPLS island and for terminating those services at an
egress LSR that is not GMPLS-capable. Further, in balanced island egress LSR that is not GMPLS-capable. Further, in balanced island
models, and in particular where there are multiple small models, and in particular where there are multiple small
(individual node) islands, the repeated conversion of signaling (individual node) islands, the repeated conversion of signaling
parameters may lead to loss of information (and functionality) or parameters may lead to loss of information (and functionality) or
mis-requests. mis-requests.
skipping to change at page 13, line 28 skipping to change at page 13, line 24
protocols and GMPLS LSRs to establish LSPs using GMPLS signaling protocols and GMPLS LSRs to establish LSPs using GMPLS signaling
protocols. LSRs that can handle both sets of protocols could work protocols. LSRs that can handle both sets of protocols could work
with both types of LSRs, and no conversion of protocols would be with both types of LSRs, and no conversion of protocols would be
needed. needed.
5.1.4. Path Computation Element 5.1.4. Path Computation Element
The Path Computation Element (PCE) [RFC4655] may provide an The Path Computation Element (PCE) [RFC4655] may provide an
additional tool to aid MPLS to GMPLS migration. If a layered network additional tool to aid MPLS to GMPLS migration. If a layered network
approach (Section 5.1.1) is used, PCEs may be used to facilitate the approach (Section 5.1.1) is used, PCEs may be used to facilitate the
computation of paths for LSPs in the different layers computation of paths for LSPs in the different layers [PCE-INT].
[PCE-INTER-LAYER].
6. Manageability Considerations 6. Manageability Considerations
Attention should be given during migration planning to how the Attention should be given during migration planning to how the
network will be managed during and after migration. For example, will network will be managed during and after migration. For example,
the LSRs of different protocol capabilities be managed separately or will the LSRs of different protocol capabilities be managed
as one management domain. For example, in the Island Model, it is separately or as one management domain? For example, in the Island
possible to consider managing islands of one capability separately Model, it is possible to consider managing islands of one capability
from the surrounding sea. In the case of islands that have different separately from the surrounding sea. In the case of islands that
switching capabilities, it is possible that the islands already have have different switching capabilities, it is possible that the
separate management in place before the migration: the resultant islands already have separate management in place before the
migrated network may seek to merge the management or to preserve the migration: the resultant migrated network may seek to merge the
separation. management or to preserve the separation.
6.1. Control of Function and Policy 6.1. Control of Function and Policy
The most critical control functionality to be applied is at the The most critical control functionality to be applied is at the
moment of changeover between different levels of protocol support. moment of changeover between different levels of protocol support.
Such a change may be made without service halt or during a period of Such a change may be made without service halt or during a period of
network maintenance. network maintenance.
Where island boundaries exist, it must be possible to manage the Where island boundaries exist, it must be possible to manage the
relationships between protocols and to indicate which interfaces relationships between protocols and to indicate which interfaces
support which protocols on a border LSR. Further, island borders are support which protocols on a border LSR. Further, island borders are
a natural place to apply policy, and management should allow a natural place to apply policy, and management should allow
configuration of such policies. configuration of such policies.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
6.2. Information and Data Models 6.2. Information and Data Models
No special information or data models are required to support No special information or data models are required to support
migration, but note that migration in the control plane implies migration, but note that migration in the control plane implies
migration from MPLS management tools to GMPLS management tools. migration from MPLS management tools to GMPLS management tools.
During migration, therefore, it may be necessary for LSRs and During migration, therefore, it may be necessary for LSRs and
management applications to support both MPLS and GMPLS management management applications to support both MPLS and GMPLS management
data. data.
The GMPLS MIB modules are designed to allow support of the MPLS The GMPLS MIB modules are designed to allow support of the MPLS
protocols and built on the MPLS MIB modules through extensions and protocols, and they are built on the MPLS MIB modules through
augmentations. This may make it possible to migrate management extensions and augmentations. This may make it possible to migrate
applications ahead of the LSRs that they manage. management applications ahead of the LSRs that they manage.
6.3. Liveness Detection and Monitoring 6.3. Liveness Detection and Monitoring
Migration will not impose additional issues for OAM above those that Migration will not impose additional issues for Operations,
already exist for inter-domain OAM and for OAM across multiple Administration, and Management (OAM) above those that already exist
switching capabilities. for inter-domain OAM and for OAM across multiple switching
capabilities.
Note, however, that if a flat PSC MPLS network is migrated using the Note, however, that if a flat PSC MPLS network is migrated using the
island model, and is treated as a layered network using tunnels to island model, and is treated as a layered network using tunnels to
connect across GMPLS islands, then requirements for a multi-layer OAM connect across GMPLS islands, then requirements for a multi-layer OAM
technique may be introduced into what was previously defined in the technique may be introduced into what was previously defined in the
flat OAM problem-space. The OAM framework of MPLS/GMPLS interworking flat OAM problem-space. The OAM framework of MPLS/GMPLS interworking
will need further consideration. will need further consideration.
6.4. Verifying Correct Operation 6.4. Verifying Correct Operation
The concerns for verifying correct operation (and in particular The concerns for verifying correct operation (and in particular,
correct connectivity) are the same as for liveness detection and correct connectivity) are the same as for liveness detection and
monitoring. Specifically, the process of migration may introduce monitoring. Specifically, the process of migration may introduce
tunneling or stitching [STITCH] into what was previously a flat tunneling or stitching [RFC5150] into what was previously a flat
network. network.
6.5. Requirements on Other Protocols and Functional Components 6.5. Requirements on Other Protocols and Functional Components
No particular requirements are introduced on other protocols. As it No particular requirements are introduced on other protocols. As it
has been observed, the management components may need to migrate in has been observed, the management components may need to migrate in
step with the control plane components, but this does not impact the step with the control plane components, but this does not impact the
management protocols, just the data that they carry. management protocols, just the data that they carry.
It should also be observed that providing signaling and routing It should also be observed that providing signaling and routing
connectivity across a migration island in support of a layered connectivity across a migration island in support of a layered
architecture may require the use of protocol tunnels (such as GRE) architecture may require the use of protocol tunnels (such as Generic
between island border nodes. Such tunnels may impose additional Routing Encapsulation (GRE)) between island border nodes. Such
configuration requirements at the border nodes. tunnels may impose additional configuration requirements at the
border nodes.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
6.6. Impact on Network Operation 6.6. Impact on Network Operation
The process of migration is likely to have significant impact on The process of migration is likely to have significant impact on
network operation while migration is in progress. The main objective network operation while migration is in progress. The main objective
of migration planning should be to reduce the impact on network of migration planning should be to reduce the impact on network
operation and on the services perceived by the network users. operation and on the services perceived by the network users.
To this end, planners should consider reducing the number of To this end, planners should consider reducing the number of
migration steps that they perform, and minimizing the number of migration steps that they perform and minimizing the number of
migration islands that are created. migration islands that are created.
A network manager may prefer the island model especially when A network manager may prefer the island model especially when
migration will extend over a significant operational period because migration will extend over a significant operational period because
it allows the different network islands to be administered as it allows the different network islands to be administered as
separate management domains. This is particularly the case in the separate management domains. This is particularly the case in the
overlay, augmented network and border peer models where the details overlay, augmented network and border peer models where the details
of the protocol islands remain hidden from the surrounding LSRs. of the protocol islands remain hidden from the surrounding LSRs.
6.7. Other Considerations 6.7. Other Considerations
A migration strategy may also imply moving an MPLS state to a GMPLS A migration strategy may also imply moving an MPLS state to a GMPLS
state for an in-service LSP. This may arise once all of the LSRs state for an in-service LSP. This may arise once all of the LSRs
along the path of the LSP have been updated to be both MPLS and along the path of the LSP have been updated to be both MPLS- and
GMPLS-capable. Signaling mechanisms to achieve the replacement of an GMPLS-capable. Signaling mechanisms to achieve the replacement of an
MPLS LSP with a GMPLS LSP without disrupting traffic exist through MPLS LSP with a GMPLS LSP without disrupting traffic exist through
make-before-break procedures [RFC3209] and [RFC3473], and should be make-before-break procedures [RFC3209] and [RFC3473], and should be
carefully managed under operator control. carefully managed under operator control.
7. Security Considerations 7. Security Considerations
Security and confidentiality is often applied (and attacked) at Security and confidentiality is often applied (and attacked) at
administrative boundaries. Some of the models described in this administrative boundaries. Some of the models described in this
document introduce such boundaries, for example between MPLS and document introduce such boundaries, for example, between MPLS and
GMPLS islands. These boundaries offer the possibility of applying or GMPLS islands. These boundaries offer the possibility of applying or
modifying the security as when crossing an IGP area or AS boundary, modifying the security as when crossing an IGP area or Autonomous
even though these island boundaries might lie within an IGP area or System (AS) boundary, even though these island boundaries might lie
AS. within an IGP area or AS.
No changes are proposed to the security procedures built into MPLS No changes are proposed to the security procedures built into MPLS
and GMPLS signaling and routing. GMPLS signaling and routing inherit and GMPLS signaling and routing. GMPLS signaling and routing inherit
their security mechanisms from MPLS signaling and routing without any their security mechanisms from MPLS signaling and routing without any
changes. Hence, there will be no additional issues with security in changes. Hence, there will be no additional issues with security in
interworking scenarios. Further, since the MPLS and GMPLS signaling interworking scenarios. Further, since the MPLS and GMPLS signaling
and routing security is provided on a hop-by-hop basis, and since all and routing security is provided on a hop-by-hop basis, and since all
signaling and routing exchanges described in this document for use signaling and routing exchanges described in this document for use
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
between any pair of LSRs are based on either MPLS or GMPLS, there are between any pair of LSRs are based on either MPLS or GMPLS, there are
no changes necessary to the security procedures. no changes necessary to the security procedures.
8. IANA Considerations 8. Acknowledgements
This informational framework document makes no requests for IANA The authors are grateful to Daisaku Shimazaki for discussion during
action. the initial work on this document. The authors are grateful to Dean
Cheng and Adrian Farrel for their valuable comments.
9. Acknowledgements 9. References
The authors are grateful to Daisaku Shimazaki for discussion during 9.1. Normative References
initial work on this document. The authors are grateful to Dean Cheng
and Adrian Farrel for their valuable comments.
10. Editor's Addresses [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Kohei Shiomoto, Editor [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
NTT and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Midori 3-9-11 Tunnels", RFC 3209, December 2001.
Musashino, Tokyo 180-8585, Japan
Phone: +81 422 59 4402
Email: shiomoto.kohei@lab.ntt.co.jp
11. Authors' Addresses [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
January 2003.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, September
2003.
[RFC3784] Smit, H. and T. Li, "Intermediate System to Intermediate
System (IS-IS) Extensions for Traffic Engineering (TE)",
RFC 3784, June 2004.
[RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC 3945, October 2004.
[RFC4872] Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou, Ed.,
"RSVP-TE Extensions in Support of End-to-End Generalized
Multi-Protocol Label Switching (GMPLS) Recovery", RFC 4872,
May 2007.
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
"GMPLS Segment Recovery", RFC 4873, May 2007.
[RFC5073] Vasseur, J., Ed., and J. Le Roux, Ed., "IGP Routing
Protocol Extensions for Discovery of Traffic Engineering
Node Capabilities", RFC 5073, December 2007.
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, October 2005.
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
[RFC4726] Farrel, A., Vasseur, J.-P., and A. Ayyangar, "A Framework
for Inter-Domain Multiprotocol Label Switching Traffic
Engineering", RFC 4726, November 2006.
[RFC5150] Ayyangar, A., Kompella, A., Vasseur, JP., and A. Farrel,
"Label Switched Path Stitching with Generalized
Multiprotocol Label Switching Traffic Engineering", RFC
5150, February 2008.
[RFC5146] Kumaki, K., Ed., "Interworking Requirements to Support
Operation of MPLS-TE over GMPLS Networks", RFC 5146, March
2008.
[MLN-REQ] Shiomoto, K., Papadimitriou, D., Le Roux, J.L., Vigoureux,
M., and D. Brungard, "Requirements for GMPLS-Based Multi-
Region and Multi-Layer Networks (MRN/MLN)", Work in
Progress, January 2008.
[PCE-INT] Oki, E., Le Roux , J-L., and A. Farrel, "Framework for
PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering,"
Work in Progress, January 2008.
10. Contributors' Addresses
Dimitri Papadimitriou Dimitri Papadimitriou
Alcatel Alcatel
Francis Wellensplein 1, Francis Wellensplein 1,
B-2018 Antwerpen, Belgium B-2018 Antwerpen, Belgium
Phone: +32 3 240 8491 Phone: +32 3 240 8491
Email: dimitri.papadimitriou@alcatel-lucent.be EMail: dimitri.papadimitriou@alcatel-lucent.be
Jean-Louis Le Roux Jean-Louis Le Roux
France Telecom France Telecom
av Pierre Marzin 22300 av Pierre Marzin 22300
Lannion, France Lannion, France
Phone: +33 2 96 05 30 20 Phone: +33 2 96 05 30 20
Email: jeanlouis.leroux@orange-ftgroup.com EMail: jeanlouis.leroux@orange-ftgroup.com
Deborah Brungard Deborah Brungard
AT&T AT&T
Rm. D1-3C22 - 200 S. Laurel Ave. Rm. D1-3C22 - 200 S. Laurel Ave.
Middletown, NJ 07748, USA Middletown, NJ 07748, USA
Phone: +1 732 420 1573 Phone: +1 732 420 1573
Email: dbrungard@att.com EMail: dbrungard@att.com
Zafar Alli Zafar Ali
Cisco Systems, Inc. Cisco Systems, Inc.
EMail: zali@cisco.com EMail: zali@cisco.com
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
Kenji Kumaki Kenji Kumaki
KDDI Corporation KDDI Corporation
Garden Air Tower Garden Air Tower
Iidabashi, Chiyoda-ku, Iidabashi, Chiyoda-ku,
Tokyo 102-8460, JAPAN Tokyo 102-8460, JAPAN
Phone: +81-3-6678-3103 Phone: +81-3-6678-3103
Email: ke-kumaki@kddi.com EMail: ke-kumaki@kddi.com
Eiji Oki Eiji Oki
NTT NTT
Midori 3-9-11 Midori 3-9-11
Musashino, Tokyo 180-8585, Japan Musashino, Tokyo 180-8585, Japan
Phone: +81 422 59 3441 Phone: +81 422 59 3441
Email: oki.eiji@lab.ntt.co.jp EMail: oki.eiji@lab.ntt.co.jp
Ichiro Inoue Ichiro Inoue
NTT NTT
Midori 3-9-11 Midori 3-9-11
Musashino, Tokyo 180-8585, Japan Musashino, Tokyo 180-8585, Japan
Phone: +81 422 59 3441 Phone: +81 422 59 3441
Email: inoue.ichiro@lab.ntt.co.jp EMail: inoue.ichiro@lab.ntt.co.jp
Tomohiro Otani Tomohiro Otani
KDDI Laboratories KDDI Laboratories
Email: otani@kddilabs.jp EMail: otani@kddilabs.jp
12. References
12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels," BCP 14, IETF RFC 2119, March 1997.
[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.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) Extensions ", RFC 3473, January 2003.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, September
2003.
[RFC3784] Smit, H. and T. Li, "Intermediate System to Intermediate
System (IS-IS) Extensions for Traffic Engineering (TE)",
RFC 3784, June 2004.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008
[RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching
Architecture", RFC 3945, October 2004.
[RFC4872] Lang, J. P., Rekhter, Y., Papadimitriou, D. (Editors), "
RSVP-TE Extensions in support of End-to-End Generalized
Multi-Protocol Label Switching (GMPLS)-based Recovery",
RFC4872, May 2007.
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., Farrel, A.,
"GMPLS Based Segment Recovery", RFC 4873, May 2007.
[RFC5073] Vasseur, Le Roux, editors, "IGP Routing Protocol
Extensions for Discovery of Traffic Engineering Node
Capabilities", RFC 5073, Decemer 2007.
12.2. Informative References
[RFC4206] Kompella, K., and Rekhter, Y., "Label Switched Paths (LSP)
Hierarchy with Generalized Multi-Protocol Label Switching
(GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005.
[RFC4655] A. Farrel, JP. Vasseur and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
[RFC4726] Farrel, A., Vasseur, J.P., Ayyangar, A., " A Framework for
Inter-Domain Multiprotocol Label Switching Traffic
Engineering", RFC4726, November 2006.
[MLN-REQ] Shiomoto, K., Papadimitriou, D., Le Roux, J.L., Vigoureux,
M., Brungard, D., "Requirements for GMPLS-based multi-
region and multi-layer networks (MRN/MLN)", draft-ietf-
ccamp-gmpls-mln-reqs, work in progress.
[MPLS-OVER-GMPLS] Kumaki, K., et al., " Interworking Requirements to
Support operation of MPLS-TE over GMPLS networks", draft-
ietf-ccamp-mpls-gmpls-interwork-reqts, work in progress.
[PCE-INTER-LAYER] Oki, E., Le Roux , J-L,. and Farrel, A., "Framework
for PCE-Based Inter-Layer MPLS and GMPLS Traffic
Engineering," draft-ietf-pce-inter-layer-frwk, work in
progress.
[STITCH] Ayyangar, A., Vasseur, JP. "Label Switched Path Stitching Editor's Address
with Generalized MPLS Traffic Engineering", draft-ietf-
ccamp-lsp-stitching, work in progress.
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk-05 January 2008 Kohei Shiomoto
NTT
Midori 3-9-11
Musashino, Tokyo 180-8585, Japan
Phone: +81 422 59 4402
EMail: shiomoto.kohei@lab.ntt.co.jp
13. Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2008). Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
14. Intellectual Property Intellectual Property
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The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
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