Network working Group W. Imajuku (ed.) NTT
Internet-Draft T. Otani (ed.) KDDI R&D Labs.
Category: Informational N. Bitar (ed.) Verizon
Expires December 2008 June 11 2008
Service Provider Requirements for Ethernet control with GMPLS
draft-ietf-ccamp-ethernet-gmpls-provider-reqs-00.txt
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Abstract
Generalized Multi-Protocol Label Switching (GMPLS) is applicable to
Ethernet switches supporting Provider Backbone Bridge Traffic
Engineering (PBB-TE) networks. The GMPLS controlled Ethernet label
switch network not only automates creation of Ethernet Label Switched
Paths(Eth-LSPs), it also provides sophisticated Eth-LSP recovery
Mechanisms such as protection and restoration of an Eth-LSP. This
document describes the requirements for the set of solutions of GMPLS
controlled Ethernet label switch networks.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
3. Reference model . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Single-layer network . . . . . . . . . . . . . . . . . . . 3
3.2. Multi-layer network . . . . . . . . . . . . . . . . . . . 4
4. Requirements for Ethernet layer control . . . . . . . . . . . 5
4.1. Control plane architecture and functionality . . . . . . 5
4.1.1. In-band control plane channel . . . . . . . . . . . . . . 5
4.1.2 Neighbor discovery mechanism . . . . . . . . . . . . . . 5
4.2. Ethernet LSP control . . . . . . . . . . . . . . . . . . 5
4.2.1. Prevention of Loops . . . . . . . . . . . . . . . . . . . 5
4.2.2. Service Control . . . . . . . . . . . . . . . . . . . . . 6
4.2.3 P2MP and MP2MP LSP . . . . . . . . . . . . . . . . . . . 6
4.3. OA&M related functionality . . . . . . . . . . . . . . . 6
4.4. Protection and restoration Related functionalities . . . 6
4.5. Link Aggregation Group related functionalities . . . . . 6
4.5.1 Failure or deletion of LAG member link . . . . . . . . . 7
4.5.2 Recovery or addition of LAG member link . . . . . . . . . 7
4.6. Inter-domain Ethernet LSP . . . . . . . . . . . . . . . . 7
4.7. Multi-layer network . . . . . . . . . . . . . . . . . . . 7
4.7.1. Dynamic formation of LAG . . . . . . . . . . . . . . . . 7
4.7.2. Other requirements . . . . . . . . . . . . . . . . . . . 7
4.8 Scalability . . . . . . . . . . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.1. Normative references . . . . . . . . . . . . . . . . . . 8
7.2. Informative references . . . . . . . . . . . . . . . . . . 9
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
9. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 10
Intellectual Property and Copyright Statements . . . . . . . . . . 11
Copyright Statement. . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
Scalability and manageability of Ethernet switch networks has
continuously improved, and the deployment of Ethernet switches
supporting Provider Bridging (PB) [IEEE802.1ad] has became one of the
solutions for service providers to provide enterprise WAN/LAN services.
IEEE standardization activities of Provider Backbone Bridge(PBB)
[IEEE 802.1ah] and PBB for Traffic Engineering (PBB-TE) [IEEE802.1Qay]
provide an opportunity not only for enhancing the scalability,
manageability, and controllability of the Ethernet service networks,
but also for more efficiently deploying access/metro access networks.
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Generalized Multi-Protocol Label Switching (GMPLS) provides the
framework for handling and controlling various types of switching
technologies, namely packet switching with various label formats TDM
switching, and wavelength switching [RFC3945]. Therefore, the combined
use of GMPLS and PBB-TE is a fairly suitable "use case" that
contributes to enhancing the flexibility of Ethernet Label Switched
Path (Eth-LSP) over Ethernet switch networks without defining
additional connection layers.
This document describes requirements for GMPLS protocols to control
Ethernet label switch networks and comprises mainly two parts.
The first one is the requirements for GMPLS extension for
controlling Ethernet layer. The second one includes the requirements
for GMPLS extensions to support multi-layer operation. Although a
large portion of requirements in the second scope coincides with the
description in [Interwk-fwk] and [Interwk-req], some of important
requirements are also described in this document.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC 2119
[RFC2119].
3. Reference model
3.1 Single Layer
This document describes requirements based on the reference model
depicted in Fig. 1. The first reference model is an intra-domain
and single layer GMPLS controlled Ethernet label switching network
in which Eth-LSPs traverse over between Back Bone Core Bridges
(BCBs) or Back Bone Edge Bridges (BEBs).
--------
| LSR3 |__ P-based IF
-------- ----- _____|(IB-BEB)|__ S-tagged IF
P-based IF | LSR1 |____|LSR2 | | |__ I-tagged IF
S-tagged IF |(IB-BEB)| |(BCB)| --------
I-tagged IF | | | |_____ --------
-------- ----- | LSR4 |
| (B-BEB)|
| |__ I-tagged IF
--------
| GMPLS Eth-LSP |
| (BVID/BMAC) |
|<---------------|
Figure 1 Single layer GMPLS controlled PBB-TE network
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The BEBs provide mainly three types of service interfaces, namely
Port based service interface (P-based IF), S-tagged service interface
(S-tagged IF), and I-tagged service Interface (I-tagged IF)
[IEEE802.1ah]. The "P-based IF" and "S-tagged IF" are connected to the
I-component of a BEB (I-BEB), while the I-tagged IF is connected to
the B-component of a BEB (B-BEB). "S-tagged IF" can perform various
types of mapping between Service VLAN ID (S-VID) and Backbone
instance Service Identifier (I-SID). Here, S-VID is assigned within
customer network domain or Provider Bridge (PB) domain. On the other
hand, I-SID is defined between I-components of BEBs.
3.2 Multi-layer
The second reference model is Ethernet and L1 (such as TDM, OTN,
etc) multi-layer network. Each Ethernet switch node behaves as
a border node between the Ethernet layer and optical Layers.
Each BCB or BEB terminates Optical Label Switched Path (O-LSPs)
with Ethernet encoding type and some O-LSPs dynamically form LAG.
Thus, some Eth-LSPs traverse over multiple O-LSPs, while other
Eth-LSPs traverse over single O-LSPs.
Also, it is technically possible to form multiple layer Ethernet
switch networks. Namely, the reference model is defined as the case
that Ethernet switch network substitutes L1 network in Fig.2, and
realizes MAC in MAC Ethernet transport.
The routing information of optical layer may be isolated (overlay
model), shuffled (peer model), or virtualized with FA-LSPs
(augmented model) for Ethernet switch layer.
-------- ------ --------
P-based IF __| LSR1 | | LSR2 | | LSR3 |__ P-based IF
S-tagged IF __|(IB-BEB)| | (BCB)| |(IB-BEB)|__ S-tagged IF
I-tagged IF __| | | | | |__ I-tagged IF
-------- ------ --------
| | ||LAG LAG||
......................|...........|..||..........||...................
| | || ||
---+---- ------ ------
| LSR A |_____|LSR B |_____|LSR C |
| (LSC) | |(LSC) | WDM |(LSC) |
-------- ------ ------
| GMPLS Eth-LSP (BVID/BMAC)|
|<------------------------>|
| O-LSP | | O-LSP |
|<--------->| |<-------->|
Figure 2 Multi-layer GMPLS controlled Ethernet label switched network
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4. Requirements
Section 4.1 to 4.6 describe requirements for single layer Ethernet
label swicth network based on the reference model from Fig.1.
In addition, section 4.7 describes requirements for multiple
layer network with Ethernet layer and circuit switch layer (such as
wavelength switched layer and so on). Finally, section 4.8 describes
generic requirements applicable to single and multiple layer
networks.
4.1 Control plane architecture and functionality
4.1.1 In-band control plane channel
The solution should be able to establish in-band control channel,
while preserving the solution of out-band control channel.
The solution should include negotiation mechanism to specify bandwidth
and priority of control-channel between peer Ethernet switches.
4.1.2 Neighbor discovery mechanism
The solution MUST be able to realize automatic neighbor discovery
as realized in current PB or PBB networks.
Namely, the solution MUST support an automatic negotiation mechanism
to exchange information of Node ID, TE-Link ID, Data-link ID
(in the case of link Bundling), and IP address of the control channel.
On the other hand, the extension should be minimized by making use
of [IEEE 802.1AB].
4.2 Ethernet LSP control
4.2.1 Prevention of Loops
The solution should have reliability to prevent creating loops of
Eth-LSPs. Specifically if the solution supports numbered TE-Link
addressing, the solution should define a methodology and protocol
extensions if needed to detect or prevent loops.
4.2.2 Service control
The solution should control various types of service interfaces
defined in [IEEE802.1ah]. The service types of Egress port
1) Port based service interface
2) S-tagged service interface
a) one-to-one mapping of S-VIDs to I-SIDs
b) bundled mapping of S-VIDs to I-SIDs
such as many-to-one, all-to-one, transparent mapping
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3) I-tagged service interface
should be controllable in addition to assignment of Egress port
itself.
Also, the solution should be flexible to following operational
scenarios,
1) Any change of mapping of S-VIDs to I-SIDs
2) Flexibility to nest or stitch higher layer Eth-LSPs.
3) Any change of bandwidth of Eth-LSPs. Here, the solution
of bandwidth modification scenario may include bundling
of multiple Eth-LSPs.
4.2.3 P2MP and MP2MP requirements
Detail requirements will be described in future version.
4.3 OA&M related functionality
OAM mechanisms must be defined for GMPLS controlled E-LSPs.
Since the data plane is still Ethernet based, the mechanisms
should capitalize on existing IEEE802.1ad and Y.1731 mechanisms.
Also, the solution should provide admin status control mechanism
to coordinate with Connectivity Fault Management (CFM)
functionality [IEEE802.1ag].
4.4 Protection and Restoration related functionality
Detail requirements will be described in future version.
4.5 Link Aggregation Group (LAG) related functionality
Link Aggregation is beneficial functionality to realize reliable
Ethernet label switched networks. The availability of connection
between peer Ethernet switches can be enhanced in the case of
single link failure, if member links of the LAG are diversely
routed. In this operational scenario, LAG provides for link protection
functionality.
The solution should include methodology to explicitly assign
the links forming LAG a desired link type (which is similar sense to
assign link protection type described in [RFC3471]).
4.5.1 Failure or deletion of LAG member link
The solution should include functionality to prioritize Eth-LSPs,
specifically when total bandwidth of Eth-LSPs exceeds total bandwidth
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of healthy LAG members after the failure of one or more LAG member
links.
The solution should provide for rerouting an Eth-LSP setup over a
failed member link in a LAG to another member link in the LAG.
4.5.2 Recovery or addition of LAG member link
The solution should include functionality to re-optimize Eth-LSP
paths after the addition of a LAG member link, i.e. reversion of
failed Eth-LSPs after the failure of the LAG member link, or
reallocation of other Eth-LSPs traversing congested Links after
the addition of LAG member link.
4.6 Inter-domain Ethernet LSP
The solution should take into account possible future extension
to control inter-domain Eth-LSPs. Here, the possible extensions are
Eth-LSPs traverse over
1) I-tagged service interfaces
2) S-tagged service interfaces, and
3) C-tagged service interfaces.
4.7 Multi-layer network
4.7.1 Dynamic formation of LAG
The solution should include dynamic formation of a LAG after the
creation or deletion of optical LSPs which interconnect ports of
Ethernet switches.
4.7.2 Other requirements
The architecture and requirements for MPLS-GMPLS inter-working are
described in [Interwk-fwk] and [Interwk-req]. Some of the requirements
described in [Interwk-req] are valid even for the case of GMPLS-GMPLS
interworking between Ethernet label switched network and L1 network.
In other words,
1) End-to-End signaling of Eth-LSPs
2) Triggered establishment of L1 LSPs
3) Avoiding complexity and risks.
should be satisfied even for GMPLS control plane for Ethernet. For
more details, see [Interwk-req] and MPLS-TE client network written
in the document should be understood as Ethernet client network.
Regarding to routing issue,
1) Advertisement of Ethernet label switch network information
via L1 GMPLS networks
2) Selective Advertisement of Ethernet label switched network
information via a Border node
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should be satisfied even in the case of GMPLS-GMPLS inter-working.
Note that there is significant difference between MPLS-TE and GMPLS
controlled Ethernet from the view point of methodology to create
control channel.
4.8 Scalability
The solution MUST be designed to scale according to following metrics.
- Number of nodes
- Number of TE-Links
- Number of LSPs
- Number of service ports
- Number of bundled S-VLANs mapped to I-SID and Eth-LSPs.
5. Security considerations
TBD
6. IANA considerations
TBD
7. References
7.1 Normative References
[IEEE802.1ad] IEEE Computer Society, "Virtual Bridged Local Area
Networks - Amendment 4 : Provider Bridges", P802.1ad/D6.0,
Draft, Work in Progress
[IEEE802.1ah] "IEEE standard for Provider Backbone Bridges", work in
progress.
[IEEE802.1Qay] "IEEE standard for Provider Backbone Bridges Traffic
Engineering", work in progress.
[RFC3945] E. Mannie (Editor), "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC 3945, October 2004.
[IEEE 802.1AB] "IEEE Standard for Local and Metropolitan Area
Networks, Station and Media Access Control Connectivity
Discovery".
[IEEE802.3] IEEE Computer Society, "Amendment to Carrier Sense
Multiple Access with Collision Detection (CAMS/CD)
Access Method and Physical Layer Specifications ?
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Aggregation of Multiple Link Segements, " P802.3ad,
March 2000.
[IEEE802.1ag] IEEE Computer Society, "Virtual Bridged Local Area
Networks - Amendment 5 : Connectivity Fault Management",
P802.1ag/D5.2, Draft, Work in Progress
[RFC3471] L.Berger et al., "Generalized Multi-Protocol Label
Switching (GMPLS) - Signaling Functional Description",
RFC 3471, January 2003.
7.2 Informative References
[Interwk-frw] Shiomoto, K., Papadimitriou, D., Le Roux, J.L.,
Brungard, D., Kumaki, K., Ali, Z., Oki, E., Inoue, I.,
Otani, T., "Framework for MPLS-TE to GMPLS migration",
draft-ietf-ccamp-mpls-gmpls-interwork-fmwk, work in
progress.
[Interwk-req] Kumaki, K., Otani, T., Okamoto, S., Fujihara,
K., Ikejiri, Y., "Interworking Requirements to Support
operation of MPLS-TE over GMPLS Networks", draft-ietf-
ccamp-gmpls-mln-reqs, work in progress.
8. Acknowledgments
The authors would like to thank Mr. Allan McGuire, Mr. Jullien
Meuric, Mr. Lou Berger and Mr. Don Fedyk for their valuable
comments.
9. Authors' Addresses
Wataru Imajuku (ed.)
NTT Network Innovation Labs
1-1 Hikari-no-oka, Yokosuka, Kanagawa
Japan
Phone: +81-(46) 859-4315
Email: imajuku.wataru@lab.ntt.co.jp
Yoshiaki Sone
NTT Network Innovation Labs
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1-1 Hikari-no-oka, Yokosuka, Kanagawa
Japan
Phone: +81-(46) 859-2456
Email: sone.yoshiaki@lab.ntt.co.jp
Muneyoshi Suzuki
NTT Access Service System Labs
1-6 Nakase, Mihama-ku, Chiba
Japan
Phone: +81-(43) 211-8282
Email: suzuki.muneyoshi@lab.ntt.co.jp
Kazuhiro Matsuda
NTT Network Innovation Labs
1-1 Hikari-no-oka, Yokosuka, Kanagawa
Japan
Phone: +81-(46) 859-3177
Email: matsuda.kazuhiro@lab.ntt.co.jp
Nabil Bitar (ed.)
Verizon
40 Sylvan Road
Waltham, MA 02451
Email: nabil.n.bitar@verizon.com
Kenichi Ogaki
KDDI R&D Laboratories, Inc.
2-1-15 Ohara Fujimino-shi
Saitama, 356-8502 Japan
Phone: +81-49-278-7897
Email: ogaki@kddilabs.jp
Tomohiro Otani (ed.)
KDDI R&D Laboratories, Inc.
2-1-15 Ohara Fujimino-shi
Saitama, 356-8502 Japan
Phone: +81-49-278-7357
Email: otani@kddilabs.jp
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