Network Working Group G. Xie
Internet-Draft X. Fu
Intended status: Standards Track ZTE Corporation
Expires: January 6, 2011 July 5, 2010
Requirement for Information extension in electro-optical multi-layer
network
draft-xie-ccamp-elec-opt-network-info-ext-req-00
Abstract
This memo provides extending information for electro-optical multi-
layer network under the control of Generalized MPLS(GMPLS). In
particular we provide electro-optical conversion capability that
describes the function between Optical Cross Connect(OXC) and Digital
Cross Connect(DXC). The information of electro-optical conversion
capability is used for extending multi-layer network(MLN) information
model and Wavelength Switched Optical network(WSON) information
model.
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].
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 6, 2011.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Information extension . . . . . . . . . . . . . . . . . . . . 5
3.1. Extending information . . . . . . . . . . . . . . . . . . 5
3.2. Extending mode . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Extending protocols . . . . . . . . . . . . . . . . . . . 8
4. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
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1. Introduction
A multi-layer network (MLN) is a Traffic Engineering (TE) domain
comprising multiple data plane switching layers either of the same
ISC (e.g., TDM) or different ISC (e.g., TDM and PSC) and controlled
by a single GMPLS control plane instance[RFC5212]. In a MLN, network
elements may be single-switching-type-capable or multi-switching-
type-capable nodes. Single-switching-type-capable nodes have TE
links with the same ISC value. Multi-switching-type-capable nodes
have TE links with the different ISCs value. Nodes are classified as
"simplex" or "hybrid" nodes. A simplex node can terminate data links
with different switching capabilities where each data link is
connected to the node by a separate link interface. A hybrid node
can terminate data links with different switching capabilities where
the data links are connected to the node by the same interface.
Interface Switching Capability Descriptor(ISCD) is defined to
describe the ISC of link RFC 4203 [RFC4203]. In a MLN without hybrid
nodes, ISCs at both ends of the link are different if the link is
between two different ISC nodes. For example, [TDM, LSC] is a link
between a Digital Cross Connect(DXC) and an Optical Cross
Connect(OXC) RFC 4202 [RFC4202]. For a hybrid node, Interface
Adjustment Capability Descriptor (IACD) is the capability of the
internal adjustment capability between two link ends with different
ISC. For example, in a hybrid node with a DXC and a OXC that
interconnect with the internal links, IACD will be add to the routing
information of a TE link which ISC is LSC.
Since optical network is block, so we need flood the block
information in the optical network. Wavelength Switched Optical
Network(WSON) extend the block information.
But electro-optical multi-layer network need more information. This
document defines the information extension of electro-optical
network.
2. Motivation
A MLN with optical network and electronic network is shown in Figure
1.
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Node A Node B Node C Node D
-------- -------- -------- --------
| |if-1 | |if-3 | |if-5 | |
| DXC |---------| OXC |---------| OXC+ |---------| OXC+ |
| | if-2| | if-4| DXC | if-6| |
-------- -------- -------- --------
if-7| |if-13 |if-12
| | |
| if-14| |
| -------- -------- |
| if-8| |if-9 | | |
+-------------| OXC |---------| OXC |-------------+
| | if-10| |if-11
-------- --------
Node E Node F
Figure 1. Electro-optical multi-layer network.
Node C is a hybrid node and other nodes are single-switching-type-
nodes. So we can get four paths: A-B-C-D, A-B-C-F-D, A-E-F-D,
A-E-F-C-D. In case that electro-optical conversion is at if-2, if-8,
if-11 and the internal links within node c. And in case the
modulation type of if-2 and if-8 is DPSK and the modulation type of
if-11 is DQPSK. In node C, the modulation type of some internal
links is DPSK and the modulation type of others is DQPSK. So A-E-F-D
is not available and others are not sure to be available.
Since optical network is blocking, the blocking information need to
be described. The typical node model of optical network is shown if
figure 2.
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......................................................
: ROADM :
: :
: --- -------- --- :
: | | | | ----------------- | | :
: | D |--->| |-->| Wavelength Conv |-->| | :
: | E | | | ----------------- | M | :
------->| M | | N x N | ----------------- | U |------->
: | U |--->| |-->| Regeneration | | X | :
: | X | | | ----------------- | | :
: | | | | | | :
: | |--->| |------------------------>| | :
: --- -------- --- :
:.............| | ^ ^.................................:
| | | |
v v | |
D D A A
r r d d
o o d d
p p 2 2
2 2 3 4
1 2
Figure 2. ROADM model of Node C.
WSON extends the blocking information, including connectivity,
wavelength conversion capability and regeneration capability. But
from the WSON information model, there are no information that
describes electro-optical conversion capability with add ports and
drop ports.
So we need extend MLN information model and WSON information model to
apply for electro-optical network.
3. Information extension
3.1. Extending information
In the optical network, optical transmitter(OT) and optical
receiver(OR) are used for optical-electronic converting. The
characteristics of optical transmitter and optical receiver include
tunable or not, tuning range, tuning time, modulation type, Forward
Error Correction(FEC) type, signal type and so on. Every
characteristic is optional. More than one type of modulation/FEC/
signal can be supported by optical transmitter and optical receiver.
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The main extending information is electro-optical conversion
information that includes wavelength tunable capability and signal
processing capability. Wavelength tunable capability describes the
wavelength tuning technology of optical transmitter. And signal
processing capability describes the technology of electronic signal
processing of optical transmitter or optical receiver. Wavelength
tunable capability includes tunable or not, tuning range and tuning
time. Signal processing capability includes FEC technology,
modulation technology and electronic signal type.
<Wavelength tunable capability>::=<Tunable><Tuning range><Tuning time>;
<Electro-optical conversion capability>::=<FEC type list><Modulation type list><Signal type list>;
For hybrid node, we need extend information of internal links. And
each internal link has a group of optical transmitter and optical
receiver, so internal link information includes wavelength tunable
capability and electro-optical conversion capability.
<Internal link>::=<link ID><Wavelength tunable capability><Electro-optical conversion capability>;
<Internal link list>:=<Internal link><Internal link list>;
3.2. Extending mode
In different scenarios, we have different extending modes. In the
electro-optical multi-layer network without hybrid nodes, there is a
link between optical node and electronic node. If optical
transmitter and optical receiver are at optical node side port or
electronic node side port, electro-optical conversion information
will be add to the routing information of optical node side port or
electronic node side port. For example, if optical transmitter and
optical receiver are at optical node side port, electro-optical
conversion information will be add to the routing information of
optical node side port. This scenario is shown in figure 3. And
optical transmitter and optical receiver are at electronic node side
port, electro-optical conversion information will be add to the
routing information of electronic node side port. This scenario is
shown in figure 4.
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...................... .............
: Node B : : Node A :
: : : :
: ----- : : ----- :
: | | ---- : : | | :
: | |<---| OT |<-------------------| | :
: | OXC | ---- : : | DXC | :
: | | ---- : : | | :
: | |--->| OR |------------------->| | :
: | | ---- : : | | :
: ----- : : ----- :
:.....................: :...........:
Figure 3. OT and OR are at OXC
............ .................
: Node B : : Node A :
: : : :
: ----- : : ----- :
: | | : : ---- | | :
: | |<-------------------| OT || | :
: | OXC | : : ---- | DXC | :
: | | : : ---- | | :
: | |------------------->| OR || | :
: | | : : ---- | | :
: ----- : : ----- :
:...........: :................:
Figure 4. OT and OR are at DXC
So link information will include wavelength tunable capability and
signal processing capability, which is flooded by route protocol.
<Link Info>::=<ISCD><Wavelength tunable capability><Signal processing capability>;
For the hybrid node, electro-optical conversion information will be
add to information of internal links. This scenario is shown in
figure 5.
<Node Info>::=<Internal link list>;
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..................
: Node C :
: :
: ----------- :
: | | :
: | OXC | :
: | | :
: ----------- :
: ^ | Internal Link
: | v :
: ---- ---- :
: | OT | | OR | :
: ---- ---- :
: ----------- :
: | | :
: | DXC | :
: | | :
: ----------- :
:.................:
Figure 5. OT and OR are at Hybrid node.
3.3. Extending protocols
There are some protocols which need be extended.
o OSPF or ISIS need be extended;
o Signal protocol need be extend to inform the internal link when
LSP is creating;
o PCEP protocol need be extended to inform the internal link when
PCE is used for path computation.
4. Example
We use modulation type for example. For figure 1, the link
information will be extended.
<Link Info(if-2)>::=<ISCD(LSC)><Wavelength tunable capability ><electro-optical conversion capability(DPSK)>;
<Link Info(if-8)>::=<ISCD(LSC)><Wavelength tunable capability ><electro-optical conversion capability(DPSK)>;
<Link Info(if-11)>::=<ISCD(LSC)><Wavelength tunable capability ><electro-optical conversion capability(DQPSK)>;
The hybrid node model is shown in figure 6.
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.............................................................
: ROADM :
: :
: --- --------------- --- :
: | | | | ----------------- | | :
: | D |--->| |-->| Wavelength Conv |-->| | :
if-4 : | E | | | ----------------- | M | : if-13
------->| M | | N x N | ----------------- | U |------->
: | U |--->| |-->| Regeneration | | X | :
: | X | | | ----------------- | | :
: | | | | | | :
: | |--->| |------------------------>| | :
: --- --------------- --- :
:.............|...|...^...^..................................:
| | | |
v v | | Internal Link 31, 32
- - - -
|O| |O| |O| |O|
|R| |R| |T| |T|
|1| |2| |1| |2|
- - - -
-------------
| |if-5
| DXC |<------->
| |
-------------
Figure 6. Hybrid Node C with extending information.
In case modulation type of optical transmitter 1 and optical receiver
1 is DPSK, and modulation type of optical transmitter 1 and optical
receiver 1 is DQPSK. Internal link 31 is identified as optical
transmitter 1, optical receiver 1, drop port 21 and add port 23. And
internal link 31 is identified as optical transmitter 1, optical
receiver 1, drop port 21 and add port 23.
<Node Info>::=<Internal link(31)><Internal link(32)>;
<Internal link(31)>::=<Link ID(31)><Wavelength tunable capability ><Electro-optical conversion capability(DPSK)>;
<Internal link(31)>::=<Link ID(31)><Wavelength tunable capability ><Electro-optical conversion capability(DQPSK)>;
<Link info(if-4)>::=<ISCD(LSC)><IACD(TDM/LSC)>;
<Link info(if-13)>::=<ISCD(LSC)><IACD(TDM/LSC)>;
<Link info(if-5)>::=<ISCD(LSC)><IACD(TDM/LSC)>;
Finally, the available paths are:
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Path 1: A.1-B.2-B.3-C.4(-C.31)-C.5-D.6; In node C, the internal link
31 is used.
Path 2: A.1-B.2-B.3-C.4(-C.31-C.32)-C.13-F.14-F.11-D.6; In node C,
the internal link 31 and internal link 32 are used.
Path 3: A.7-E.8-E.9-F.10-F.14-C.13(-C.31)-C.5-D.6; In node C, the
internal link 31 is used.
5. Security Considerations
The use of control plane protocols for signaling, routing, and path
computation opens an electro-optical network to security threats
through attacks on those protocols. The data plane technology for an
electro-optical network does not introduce any specific
vulnerabilities, and so the control plane may be secured using the
mechanisms defined for the protocols discussed.
For further details of the specific security measures refer to the
documents that define the protocols ([RFC3473], [RFC4203], [RFC4205],
[RFC4204], and [RFC5440]). [GMPLS-SEC] provides an overview of
security vulnerabilities and protection mechanisms for the GMPLS
control plane.
6. IANA Considerations
This document makes not requests for IANA action.
7. Acknowledgments
We'd be appreciated to thank Malcolm Betts for his review and useful
comments.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Functional Description", RFC 3471,
January 2003.
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[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching
(GMPLS) Architecture", RFC 3945, October 2004.
[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., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
[I-D.ietf-ccamp-rwa-wson-framework]
Bernstein, G., "Framework for GMPLS and PCE Control of
Wavelength Switched Optical Networks (WSON)",
draft-ietf-ccamp-rwa-wson-framework-06 (work in progress),
April 2010.
8.2. Informative References
[RFC5212] Shiomoto, K., Papadimitriou, D., Le Roux, JL., Vigoureux,
M., and D. Brungard, "Requirements for GMPLS-Based Multi-
Region and Multi-Layer Networks (MRN/MLN)", RFC 5212,
July 2008.
[RFC4202] Kompella, K. and Y. Rekhter, "Routing Extensions in
Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4202, October 2005.
[RFC4203] Kompella, K. and Y. Rekhter, "OSPF Extensions in Support
of Generalized Multi-Protocol Label Switching (GMPLS)",
RFC 4203, October 2005.
[I-D.ietf-ccamp-gmpls-mln-extensions]
Papadimitriou, D., Vigoureux, M., Shiomoto, K., Brungard,
D., and J. Roux, "Generalized Multi-Protocol Label
Switching (GMPLS) Protocol Extensions for Multi-Layer and
Multi-Region Networks (MLN/MRN)",
draft-ietf-ccamp-gmpls-mln-extensions-12 (work in
progress), February 2010.
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Authors' Addresses
Gang Xie
ZTE Corporation
Email: xie.gang@zte.com.cn
Xihua Fu
ZTE Corporation
Email: fu.xihua@zte.com.cn
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