Extensions to GMPLS RSVP-TE for Bidirectional Lightpath with the Same Wavelength draft-xu-rsvpte-bidir-wave-01 - PowerPoint PPT Presentation

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Extensions to GMPLS RSVP-TE for Bidirectional Lightpath with the Same Wavelength draft-xu-rsvpte-bidir-wave-01

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Title: Extensions to GMPLS RSVP-TE for Bidirectional Lightpath with the Same Wavelength draft-xu-rsvpte-bidir-wave-01


1
Extensions 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

2
To 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
3
Do 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

4
Shorter 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)
5
PCE 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.

6
PCE 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.

7
Next 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
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