Title: Extensions to GMPLS RSVP-TE for Bidirectional Lightpath with the Same Wavelength draft-xu-rsvpte-bidir-wave-01
1Extensions to GMPLS RSVP-TE for Bidirectional
Lightpath with the Same Wavelengthdraft-xu-rsvpt
e-bidir-wave-01
- Sugang Xu, Hiroaki Harai, Daniel King
- xsg_at_nict.go.jp, harai_at_nict.go.jp,
daniel.king_at_aria-networks.com
2To Recap Support for Bidirectional Lightpath
with the SameWavelength on Both Directions Would
Be Advantageous
- Special optical network scenarios for
bidirectional lightpath provisioning - Fixed tuned wavelength transponders
- Fixed wavelength multiplexers/demultiplexers like
AWGs - Some types of ROADM need to add/drop wavelength
simultaneously - Wavelength continuity constraint
- Solution of port-remapping problem of
bidirectional lightpath with different
wavelengths using fix-tuned wavelength media
converter (MC) -
-
- True needs of Fast Provisioning capability
- In cases of configuration errors, transceiver
failure, etc. - Quick recovery capabilities are critical to
network stability.
Lack port-remapping flexibility
With flexibility by OXC
3Do Solutions Exist?
- Two unidirectional lightpaths in converse
directions with the same wavelength (A1) - Sequentially verify the same wavelength
availability in both directions and crankback if
failure. - Label set and Upstream label crankback (A2)
- Specify wavelength on both directions
- Label set and Upstream Label set (A3)
- Add constraint in wavelength available
information updating process on both directions
in Label set and Upstream Label set - Label Set Object and Bidirectional Lightpath
(Prop) - Using LSP_ATTRIBUTES Object RFC 4420
- Upstream-and-Downstream common free wavelengths
information updating at each node and carried by
Label set
4Shorter Provisioning Time and Lower Blocking
Probability
Single wavelength occupation rate/link
Pb Blocking probability
Avg. time per hop
W Number of wavelengths
H Number of Hops A1 Uni Setups A2 With
UpLabel A3 With UpLabel set Prop With Label set
Rt Avg. provisioning time
Avg. Provisioning Time (W32, ?t0.01s)
Blocking Probability (W32)
5PCE Applicability - Link Bundling Issue
- PCE path computation problems
- May occur when computing bidirectional
lightpaths. In a GMPLS network where multiple
component links are aggregated into a link bundle
and advertised as a single bidirectional TE link,
the Traffic Engineering Database (TED) may
indicate the availability of a particular lambda
in both directions on the TE link. However, it
may actually be the case that the lambda is only
available in one direction on one component link,
and the other direction is only available on a
different component link. In this scenario,
creating an end-to-end path that uses the same
lambdas and the same component links in both
directions presents a PCE path computation
problem. - Use signaling to verify the solution received
from PCE.
6PCE Applicability - Unified Signaling Solutions
- With RWA done by PCE
- Given a routing and wavelength assignment
solution e.g. derived from a PCE, an ingress node
can put one wavelength label in Label set or a
Suggested label object to specify the wavelength.
- With only routing done by PCE
- An ingress node can set one or more available
wavelength label objects in Label set, and let
the egress node resolve the wavelength assignment
in a distributed fashion. - No interaction with PCE
- Because this signaling solution can resolve
wavelength assignment problem itself, even
without interaction with a PCE, by using an
explicit route e.g. manually, it is still
possible to establish a bidirectional lightpath.
For example, for quick recovery from failures,
bidirectional signaling may negate a PCE request.
7Next Steps
- Consensus is that support for same wavelength
bidirectional lightpath is important for quick
recovery, and fast provisioning. - Is this proposal necessary right now? Feedback
from the previous WG has been positive, but there
is a need to clarify requirements. - Do we need requirements document?
- The authors will continue to work on the draft
and would like to request additional feedback
from WG. Especially from Operators and relevant
Vendors. - Referenced in draft-bernstein-ccamp-wson-signalin
g-00.txt