GSMP Working Group Internet Draft Jun Kyun Choi(ICU)
Document: draft-ietf-gsmp-optical-spec-00.txt Min Ho Kang(ICU)
Expiration Date: April 2003 Jung Yul Choi(ICU)
Gyu Myoung Lee(ICU)
Joo Uk Um(KT)
October 2002
General Switch Management Protocol (GSMP) v3 for Optical Support
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC-2026.
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Abstract
This document describes the GSMPv3 for the support of optical switching.
GSMP controller SHOULD control optical label switches and manage optical
resources on them. This document describes the extended functions of
GSMP for optical switching and explains operational mechanisms to
implement them. It SHOULD be referred with [1] for the complete
implementation.
Conventions
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.
Table of Contents
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1. Introduction.....................................................3
2. Common Definition and Procedures for Optical Support.............3
2.1 Labels..........................................................3
2.1.1 Label for Wavelength and Fiber................................3
2.1.2 Label for Waveband............................................4
2.1.3 Label for optical burst ......................................4
2.1.4 Label Range...................................................4
2.2 Protection and Restoration Capability in GSMP...................4
2.2.1 Dedicated and shared recovery mechanisms......................5
2.2.2 Revertible and Non-revertible mode............................5
2.3 GSMP support for optical switching systems......................6
2.3.1 Capability of GSMP for optical burst switching................6
3. Connection Management Messages...................................7
3.1 General Message Definitions.....................................7
3.2 Add Branch Message..............................................7
3.3 Move Output Branch Message......................................7
3.4 Move Input Branch Message.......................................7
4. Reservation Management Messages..................................7
5. State and Statistics Messages....................................8
5.1 Statistics Messages.............................................8
6. Configuration Messages...........................................8
6.1 Switch Configuration Message....................................9
6.2 Port Configuration Message......................................9
6.3 Service Configuration Message...................................9
7. Event Messages...................................................9
8. Failure Response Codes...........................................10
9. Security Consideratons...........................................10
References..........................................................10
Acknowledgement.....................................................11
Author's Addresses..................................................11
Full Copyright Statement............................................13
1. Introduction
This document describes the extended functions and requirements of
GSMPv3 for the support of optical switching. GSMPv3 is an asymmetric
protocol to control and manage the label switch. The label switches
that are used for optical switching are all optical cross-connects
(optical-optical-optical), transparent optical cross connects
(optical-electrical-optical, frame independent).
In order for GSMP to operate between the controller and optical
switched and cross connects, optical labels, services for optical
switching, and resource abstractions MUST be defined and added to
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GSMP, since the basic optical resources which are used in connection
setup are different with them of the legacy networks.
One of the main roles of GSMP is to support restoration capabilities
of optical switches and the connection. By extending the management
messages of GSMP, this function MUST be implemented.
For the complete implementation this document MUST be referred with
[1].
2. Common Definitions and Procedures for Optical Support.
Common definitions and procedures which are not mentioned in this
document follow [1].
2.1 Labels
Labels are the basic identifier for a connection. In order to setup
connections in optical switch, new labels MUST be defined. The newly
defined labels identify the entities that are to be switched in the
optical switches. GMPLS defines packet switching capable, TDM
switching capable, lambdas switching capable, fiber switching capable
interfaces, and it introduces the needs of generalized labels to
support them [3][4]. So far, GMPLS does not defined the labels to be
used for optical switching (label formats and encoding schemes), but
GSMP MUST support the all types of label that to be defined in GMPLS.
The following lists are the labels to be supported in the optical
switching [2][3][4].
- a single fiber in a bundle
- a single waveband within a fiber
- a single wavelength within a waveband (or a fiber)
- an optical burst within a wavelength
2.1.1 Labels for Wavelength and Fiber
The label indicates a fiber or a wavelength to be used for a
connection establishment in optical switching. Value of the label
only has significance between two neighbors, and the receiver MAY
need to convert the received value into a value that has local
significance.
2.1.2 Labels for Waveband
A Waveband is a set of contiguous wavelengths which can be switched
together to a new waveband [3][4]. It MAY be desirable for an optical
cross connect to optically switch multiple wavelengths as a unit
since it MAY reduce the distortion on the individual wavelengths and
MAY allow tighter separation of the individual wavelengths. The
Waveband Label is defined to support such a waveband switching. The
waveband label can be encoded in three parts; waveband ID, start
label, and end label. The start label and the end label represent the
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lowest value wavelength and the highest value wavelengths.
2.1.3 Labels for optical burst
The label for optical burst represents the label for switching optical
burst data in time domain in a wavelength. However, this label is not
defined yet.
2.1.4 Label Range
The basic label range to be used in each port is specified by the
Port Configuration or All Port Configuration message. The Label Range
message allows the range of labels supported by a specified port to
be changed. The controller MUST allocate the label range with
consideration of optical characteristics when assigning the labels
for a connection because the connection is established per optical
burst, wavelength, waveband, and fiber in optical domain. Since the
basic label range varies in switches and the labels for the
connections can be different due to the optical characteristics, GSMP
does not treat them. However, the following lists SHOULD be
considered and the available label ranges can be applied in the Label
Range message.
- When allocating a label for a wavelength, the label SHOULD be
allocated for it with consideration of wavelength continuity. For
satisfying the requirement of wavelength continuity in a
connection, the label SHOULD be allocated to maintain the same
wavelength for it. The controller MUST manage the available labels
and support the constraint.
- The labels to be used for waveband switching MUST be contiguous,
because the waveband switching is possible only in the set of
contiguous wavelengths. The decision mechanism for the available
label range is out of scope of GSMPv3.
2.2 Protection and Restoration Capability in GSMP
The GSMP controller MUST support the protection and restoration
capabilities because the optical switch delivers several Gbps data
traffic in a single wavelength. To achieve fast protection and
restoration, the optical switch is capable of taking an action
independent of the GSMP controller, then it informs the controller
after completing the restoration [2]. This differs from the master-
slave relationship in GSMP. Therefore, the GSMP port configuration
command MUST be extended to allow autonomous protection mechanism.
The current GSMP connection management also MUST be extended to
support this function.
2.2.1 Dedicated and shared recovery mechanisms
In the dedicated protection, both working and backup path deliver the
traffic simultaneously from an ingress node to an egress node. The
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egress node of the path selects one of them as a working path
according to the received signal status from the previous node. Since
the backup path also delivers the traffic it MUST be established by
using the Add Branch message. When any link in the working path fails,
the egress node switches over from the failed working path to the
backup path without noticing the GSMP controller automatically.
After completing the recovery of the failed path, the switch reports
the fact of configuring a new connection to the controller. When the
failed original path is repaired the controller determines how to
deal with the path according to the revertible or nonrevertible mode.
In the revertible mode, the currently used backup path is changed to
the repaired original path by using the Move Input Branch message
which includes the new port and label of which values are used for
the original connection. In the nonrevertible mode, the controller
deletes the repaired original working path by using the Delete Branch
message, or uses it as a new backup path for the currently used
backup path by using the Add Branch message.
In 1:N shared protection, N working paths share the one backup path.
In a different way of the dedicated protection, the shared path does
not deliver any traffic since the controller does not know which
working paths will use it. The controller uses the Reservation
message to reserve a connection for the backup path. When a link
fails among the N working paths, the controller issues the Add Branch
message to restore the traffic through the failed working path into
the new backup path
2.2.2 Revertible and Non-revertible mode
In the revertible mode, when the failed working path is repaired, the
controller restores the currently used backup path to the original
working path. The GSMP controller MUST keep the information for the
working path. The controller issues the Move Input/Output Branch
messages with the new port and label of which values are that of the
working path to restore it. After restoring, the backup path is
deleted by using the Delete message or continuously used as a backup
purpose.
In non-revertible mode, the working path is not restored from the
currently used backup path even though it is repaired. The original
working path can be used as a new backup path by using the Add Branch
message (1+1 dedicated protection), or the Reservation message (1:N
shared protection)
2.3 GSMP support for optical switching systems
GSMP SHOULD control and manage the optical cross-connect systems as
label switches. The optical cross-connect (OXC) is a space division
switch that can switch an optical data stream on an input port to an
output port.
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The OXC system can be consist of switching fabric,
multiplexer/demultiplexer, wavelength converter, and optical-
electrical/electrical-optical converter. Multiple wavelengths are
multiplexed or demultiplexed into a fiber. Multiple fibers belongs to
a fiber bundle. A wavelength, a waveband, and a fiber can be used to
establish a connection in an optical switch. They SHOULD be
recognized at a port in the OXC since they are connection entities.
When the OXC has optical-electrical conversion at the input port and
electrical-optical conversion at the output port it is called as
opaque OXC. Or, when it processes optical data stream all optically
it is called as transparent OXC. Wavelength converter SHOULD be used
to resolve output port contention when two different connections try
to be established in a same output port. Since the wavelength
converter can work only within a limited operating range, the limited
numbers of wavelengths are used at the output port. It limits the
available wavelengths at the output port.
In order to control and manage the OXC systems, GSMP SHOULD be
located as a subset of functions for it and MUST know the current
switch, port and service configuration information. GSMP controller
SHOULD identify the connection entities at the OXC and match them
with the optical labels.
2.3.1 Capability of GSMP for optical burst switching
GSMPv3 SHOULD also support data burst switching as a new connection
entity in optical domain. As described in [9],[10], connection setup
for optical burst includes reserving time on the transport medium for
the client.
This time is characterized by two parameters: a start time and the
duration of data burst. These values MAY define a fast one-way
reservation. Upon a request for setup of a burst connection, the GSMP
controller MUST perform appropriate Connection Admission Control for
the time and duration specified. If the connection is allowed, it
MUST signal these parameters to the burst switching device to reserve
the exact bandwidth required [9],[10]. The burst switch MUST perform
the switching operation autonomously, using the synchronization
methods prescribed for the burst network it is operating in.
3. Connection Management Messages
3.1 General Message Definitions
Connection management messages, which are used for establishing,
releasing, modifying, and verifying connections across the switch by
the controller, can operate in the optical domain, as the same
mechanisms. However, it is not possible to process each packet in
optical domain so that such a traffic parameter can not be used to
specify the connection. Connection management messages also SHOULD
support the OXC restoration capabilities.
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3.2 Add Branch Message
The Add Branch message is used to setup a connection. Especially, it
MUST support restoration capabilities in the optical domain. For 1+1
dedicated protection, it is required to make an additional connection
as a backup path to protect an original connection against failure.
Additional fields are not required in the Add Branch message to
support the restoration capabilities since the two connections are
used for data traffic and an egress node selects one between them so
that they functions same. However, the controller SHOULD know the
whole statues of the switch.
3.3 Move Output Branch Message
The Move Output Branch message is used to change the current output
port label to the new output port label for re-establishing the
existing connection. It can be used to support restoration
capabilities. Since to re-establish output port of a switch at an
ingress node is to change a start point of the current connection, it
can be used for 1:1 protection or 1:N shared protection where an
ingress node begins a connection. Upon a fault occurring, in order to
setup a new backup path instead of the failed working path, the new
port in upstream node SHOULD be connected to the current connection
by using this message. Because, the ingress node also takes
responsibility for recovery, as well as the egress node.
3.4 Move Input Branch Message
The Move Input Branch message is used to change the current input
port label to the new input port label for re-establishing the
existing connection. It is also used to support restoration
capabilities. It is used for the revertible mode that is to move back
to the original connection from a backup connection after a recovery
completed. The new port/label in this message uses that of the
original connection.
4. Reservation Management Messages
The Reservation Management message that reserves resources for a
connection before establishing a connection SHOULD reserve optical
resources, such as data burst, wavelengths, a set of wavelengths for
waveband switching, and fibers. In order to use the reservation
management messages, optical resources which the OXC supports SHOULD
be defined. It can be used to support restoration capabilities for
reserving backup connections. Especially, 1:N shared protection
scheme reserves a spare connection which is reserved for N working
connections so that this MUST use the reservation request messages
for reserving a backup connection. The reserved connection identified
by the reservation ID SHOULD be informed to N working connections. In
the reservation request message, the input label and output label of
the reserving branch SHOULD be assigned. After a fault occurs, the
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recovery procedure to make a backup connection just follows the
ordinary connection setup procedure in [1].
5. State and Statistics Messages
The State and Statistics messages can be used to monitor the
statistics related to ports and connection for optical transmission.
It allows the controller to request the state and statistics of the
switch.
5.1 Statistics Messages
The statistics messages are used to query the performance statistics
related to ports and connections for optical transmission. Since the
current statistics messages in [1] report the statistics related to
traffic states per cells, or frames, the new fields SHOULD be added
into the message for querying the optical support. The Port
Statistics message requests the statistics for the ports of the
switch. The Connection Statistics message allows the controller to
report the performances and statistics of the connection itself. The
statistics elements to monitor in the OXC are following.
- signal degradation
- loss of signal
As a result of performance analysis through the statistics messages,
the new connection can be requested when the controller finds the
much degraded performance on the connection. Therefore, the
statistics message to detect a fault SHOULD be defined, but the fault
detection mechanism is out of scope of this document.
6. Configuration Messages
The configuration messages allow the controller to discover the
capabilities of optical switch. Switch configuration, port
configuration, and service configuration messages are defined for
these functions.
6.1 Switch Configuration Message
Since an optical switch MAY be able to provide connection services at
multiple transport layers, and not all switches are expected to
support the same transport layers, the switch will need to notify the
controller of the specific layers it can support. Therefore, the
switch configuration message MUST be extended to provide a list of
the transport layers for which an optical switch can perform
switching. The following lists are the possible switching layers.
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- switching per optical burst
- switching per a single wavelength
- switching per a waveband
- switching per a single fiber
- switching per a fiber bundle
6.2 Port Configuration Message
The port configuration message supplies the controller with the
configuration information related to a single port. In the OXC, the
new port types SHOULD be defined in GSMP. Port types MUST be added to
support the mix of optical signals that can operate over a single
fiber. Basically the port can be used per wavelength, per fiber, and
per fiber bundle. Moreover, the OXC can have many bays which contain
hundreds of shalves which have tens of thousands of port. Therefore,
physical bay and shelve identifiers also SHOULD be defined and
encoded in port configuration message. The port configuration
information that MAY need to be conveyed includes:
- available wavelengths per interface
- bit rate per wavelength (port)
- type of fiber
6.3 Service Configuration Message
The Service Configuration message requests the optical switch for the
configuration information of the supported services. The requested
services are identified in the service ID in the Add Branch message
or the Reservation message. The service model is defined with traffic
parameter, QoS parameter, and traffic control elements in [1], but
these parameters can not be used to specify the optical services.
Therefore this message SHOULD be modified to support optical services
with newly defined capability sets. The services supported at optical
switches SHOULD be defined for dealing with optical burst, wavelength,
waveband, and fiber connection.
7. Event Messages
The Event messages allow the switch to inform the controller of
certain asynchronous events. The asynchronous events include mainly
port states indication. The indication of these asynchronous events
related to ports can provide a port failure to the controller and it
can initiate a fault recovery mechanism.
8. Failure Response Codes
This chapter describes the failure and warning states which can occur
in setup optical connections. The following lists are the codes that
SHOULD be defined and added in the Failure Response messages. These
codes MAY be added when the services for optical switching are
defined. The code numbers will be assigned in IANA.
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- no available wavelength at a port
- no available backup link for protection
- waveband connection setup fails
- reservation for optical burst fails
9. Security Considerations
This document does not have any security concerns. The security
requirements using this document are described in the referenced
documents
References
[1] Doria, A, Sundell, K, Hellstrand, F, Worster, T, "General Switch
Management Protocol V3," RFC 3292, June 2002.
[2] Georg Kullgren, et. al., "Requirements For Adding Optical Support
To GSMPv3",draft-ietf-gsmp-reqs-03.txt, Sept. 2002
[3] Mannie, E., et. al., "Generalized Multi-Protocol Label Switching
(GMPLS) Architecture," draft-ietf-ccamp-gmpls-architecture-03.txt,
August 2002.
[4] Ashwood-Smith, D., et. al., "Generalized MPLS - Signaling
Functional Description," Internet Draft draft-ietf-mpls-generalized-
signaling-08.txt, April 2002.
[5] Rajagopalan, B., et. al., _IP over Optical Networks: A Framework,
draft-ietf-ipo-framework-02.txt (work in progress), June 2002.
[6] N. Chandhok, et. al., "IP over WDM Networks; A Summary Issue",
draft-osu-ipo-mpls-issues-00,txt, July 2000
[7] Jin Ho Hahm, Kwang-il Lee, Mark Carson, "Control Mechanisms for
Traffic Engineering in Optical Networks", drafh-hahm-te-optical-
00.txt, July 2000
[8] Daniel Awduche, WYakov Rekhter, "Multiprotocol Lambda Switching:
Combining MPLS Traffic Engineering Control with Optical
Crossconnects", IEEE Comm. Mag., March 2001
[9] C. Qiao, M. Yoo, "Choice, and Feature and Issues in Optical Burst
Switching", Optical Net. Mag., vol.1, No.2, Apr.2000, pp.36-44.
[10] OBS Ilia Baldine, George N. Rouskas, Harry G. Perros, Dan
Stevension, "JumpStart: A Just-in-time Signaling Architecture for WDM
Burst-Switching Networks", IEEE Comm. Mag., Fab. 2002.
[11] Angela Chiu, John Strans, et. al., "Impairments And Other
Constraints On Optical Layer Routing", draft-ietf-ipo-impairments-
02.txt, Feb. 2002.
[12] Luc Ceuppens, et. al., "Performance Monitoring in Photonic
Networks in support of MPL(ambda)S", draft-ceuppens-mpls-optical-
00.txt, Jung 2000.
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GSMPv3 for Optical Support October 2002
[13] Doria, A. and K. Sundell, "General Switch Management Protocol
Applicability", RFC 3294, June 2002.
Acknowledgement
This work was supported in part by the Korean Science and Engineering
Foundation (KOSEF) through OIRC project
Author's Addresses
Jun Kyun Choi
Information and Communications University (ICU)
58-4 Hwa Ahm Dong, Yusong, Daejon
Korea 305-732
Phone: +82-42-866-6122
Email: jkchoi@icu.ac.kr
Min Ho Kang
Information and Communications University (ICU)
58-4 Hwa Ahm Dong, Yusong, Daejon
Korea 305-732
Phone: +82-42-866-6136
Email: mhkang@icu.ac.kr
Jung Yul Choi
Information and Communications University (ICU)
58-4 Hwa Ahm Dong, Yusong, Daejon
Korea 305-732
Phone: +82-42-866-6208
Email: passjay@icu.ac.kr
Gyu Myung Lee
Information and Communications University (ICU)
58-4 Hwa Ahm Dong, Yusong, Daejon
Korea 305-732
Phone: +82-42-866-6231
Email: gmlee@icu.ac.kr
Young Wook Cha
Andong National University (ANU)
388 Song-Chon Dong, Andong, Kyungsangbuk-do
Korea 760-749
Phone: +82-54-820-5714
Email: ywcha@andong.ac.kr
Jeong Yun Kim
Electronics and Telecommunications Research Institute (ETRI)
161 KaJong-Dong, Yusong-Gu, Daejeon
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GSMPv3 for Optical Support October 2002
Korea 305-309
Phone: +82-42-866-5311
Email: jykim@etri.re.kr
Hormuzd Khosravi
Intel
2111 NE 25th Avenue
Hillsboro, OR 97124 USA
Phone: +1 503 264 0334
Email: hormuzd.m.khosravi@intel.com
Georg Kullgren
Nortel Networks AB
S:t Eriksgatan 115 A
P.O. Box 6701
SE-113 85 Stockholm Sweden
Email: geku@nortelnetworks.com
Jonathan Sadler
Tellabs Operations, Inc.
1415 West Diehl Road
Naperville, IL 60563
Phone: +1 630-798-6182
Email: Jonathan.Sadler@tellabs.com
Stephen Shew
Nortel Networks
PO Box 3511 Station C
Ottawa, ON
K1Y 4H7
Email: sdshew@nortelnetworks.com
Kohei Shiomoto
Email: Shiomoto.Kohei@lab.ntt.co.jp
Atsushi Watanabe
Nippon Telegraph and Telephone Corporation
807A 1-1 Hikari-no-oka, Yokosuka-shi
Kanagawa 239-0847, Japan
Email: atsushi@exa.onlab.ntt.co.jp
Satoru Okamoto
Nippon Telegraph and Telephone Corporation
9-11 Midori-cho 3-chome, Musashino-shi
Tokyo 180-8585, Japan
Email: okamoto@exa.onlab.ntt.co.jp
Avri Doria
Div. of Computer Communications
Lulea University of Technology
S-971 87 Lulea
Sweden
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GSMPv3 for Optical Support October 2002
Phone: +1 401 663 5024
EMail: avri@acm.org
Fiffi Hellstrand
Nortel Networks AB
S:t Eriksgatan 115 A
SE-113 85 Stockholm Sweden
EMail: fiffi@nortelnetworks.com
Kenneth Sundell
Nortel Networks AB
S:t Eriksgatan 115 A
SE-113 85 Stockholm Sweden
EMail: ksundell@nortelnetworks.com
Tom Worster
Phone: +1 617 247 2624
EMail: fsb@thefsb.org
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