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Summary ID - http://www.ietf.org/internet-drafts/draft-many-optical-restoration-00.txt
NAME OF I-D:
http://www.ietf.org/internet-drafts/draft-many-optical-restoration-00.txt
SUMMARY
One of the most important concepts in network management is
maintaining the survivability of networks and in particular the
survivability of optical networks. When there are link failures or
the like, any affected routes should be repaired as soon as
possible. This mechanism is also referred to as fast restoration. In
today's SONET/SDH networks, one can achieve recovery times of 50 ms
or even lower, but this mechanism depends on the 1+1 backup optical
network link resources to achieve this performance. To avoid this
resources waste in optical networks, an adaptive 1:N or M:N shared
restoration mechanism can be applied that still provides enhanced
network survivability while minimizing the waste in network
resources. When using these shared mechanisms, the protection paths
can be used to transport best-effort traffic throughout the optical
network.
This Internet Draft proposes mechanisms for restoration processes
that meet these goals in optical meshed networks, as well as the
associated signaling extensions and notification message definitions.
RELATED DOCUMENTS
http://www.ietf.org/internet-drafts/draft-many-gmpls-architecture-00.txt
http://www.ietf.org/internet-drafts/draft-ietf-mpls-generalized-signalling-04.txt
http://www.ietf.org/internet-drafts/draft-ietf-mpls-generalized-rsvp-te-03.txt
http://www.ietf.org/internet-drafts/draft-ietf-mpls-generalized-cr-ldp-03.txt
http://www.ietf.org/internet-drafts/draft-ietf-ccamp-gmpls-sonet-sdh-00.txt
http://www.ietf.org/internet-drafts/draft-ietf-isis-gmpls-extensions-01.txt
http://www.ietf.org/internet-drafts/draft-kompella-ospf-gmpls-extensions-01.txt
http://www.ietf.org/internet-drafts/draft-rs-optical-bundling-01.txt
http://www.ietf.org/internet-drafts/draft-many-ip-optical-framework-02.txt
http://www.ietf.org/internet-drafts/draft-fredette-lmp-wdm-01.txt
http://www.ietf.org/internet-drafts/draft-chiu-strand-unique-olcp-02.txt
http://www.ietf.org/internet-drafts/draft-awduche-mpls-te-optical-02.txt
http://www.ietf.org/internet-drafts/draft-many-inference-srlg-00.txt,
http://www.ietf.org/internet-drafts/draft-ietf-mpls-cr-ldp-05.txt
http://www.ietf.org/internet-drafts/draft-ietf-mpls-ldp-ft-00.txt
WHERE DOES IT FIT IN THE PICTURE OF THE SUB-IP WORK
It fits in the CCAMP WG - Control C
WHY IS IT TARGETED AT THIS WG
The CCAMP WG since this document address the control plane of
opaque and transparent Optical Transport Networks (even if some
mechanisms presented can be re-used for non-technology dependent
restoration).
Basically, there are two "way of thinking" either restoration is
a particular case of LSP setup/modification so that only notification
extensions are needed to the signalling protocol (this is the
guideline in this document) or restoration mechanisms are provided
through a specific protocol (i.e. independent from the signalling
protocol) in order to provide the restoration mechanisms. The latter
case has been followed by the following draft
- draft-bala-restoration-signaling-00.txt
It has been proposed during the last meeting to separate the
mechanisms from the "signalling extensions" in order to have
first a consensus on the mechanisms and then specify the corresponding
signalling extensions based on the definition of these mechanisms.
JUSTIFICATION
Optical restoration is one of the missing building block in the
today GMPLS architecture. In particular when speaking about all-optical
restoration since in that case failure (or Lost of Signal) are not
confined to the "link" but to the whole optical segment.
Moreover it seems obvious since IP (through GMPLS) is proposed as a
non-packet based network control protocol, that GMPLS protocol suite
(in particular GMPLS signalling) must include the mechanisms to
guarantee network survivability since this property is fundamental for
such kind of networks. It is as well recognized that restoration
mechanisms involving IP-based control plane for optical networks are
today tightly related with the optical switching time (between 5 to
10 ms) which is the minimum restoration time that we can expect today
with the current status of the optical switching technology.
This means that compared to the current protection switching time
provided by SDH/Sonet networks real efforts needs to be deployed on
the IP-based optical control plane in order to achieve efficient
restoration mechanisms. Efficiency is not the only key aspect optical
network resource sharing (in order to achieve optical resource
optimization) is also required in order to reduce the spare capacity
used when re-routing optical channels (i.e. lambda LSP). The last
key dimension is related to the robustness of the mechanism: the
proposed mechanisms should be ideally independent of the network
size (or more precisely the network diameter) and the number of
lambda-LSP to restore.
These dimensions are key issues that optical restoration mechanisms
need to cover (and so GMPLS) in order to allow wide deployment of
MPLambdaS networks.