GMPLS constraints consideration for CSPF path computation draftotaniccampgmplscspfconstraints03'txt

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GMPLS constraints consideration for CSPF path
computation draft-otani-ccamp-gmpls-cspf-constra
ints-03.txt

• Kenichi Ogaki ogaki_at_kddilabs.jp
• Tomohiro Otani otani_at_kddilabs.jp
• Arthi Ayyangar arthi_at_juniper.net
• Kireeti Kompella kireeti_at_juniper.net
• Rajiv Papneja rpapnefa_at_isocore.com

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Summary of draft

• This draft fits to the following (former?)
  charter item
• Functional specification of extensions for
  routing (OSPF, ISIS) and signalling (RSVP-TE)
  required for path establishment. Protocol formats
  and procedures that embody these extensions will
  be done jointly with the WGs supervising those
  protocols.
• This draft
• states the problem of GMPLS CSPF path computation
• Since these constraints vary and are differently
  understood among such an multiple switching
  capability and encoding environment, the path
  computation results are sometimes different.
• tries to provide the guideline to consider GMPLS
  constraint attributes for CSPF path computation
  at a source node.
• TE attributes must be dealt with correctly for
  creating GMPLS LSPs in the CSPF path computation
  considering underlying physical and logical
  technologies of links as well as nodes.

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Considered network model
Ingress Transit
Egress ----- link1-2 -----
link2-3 ----- link3-4 -----
Node1------------gtNode2------------gtNode3--
----------gtNode4 lt------------
lt------------ lt------------
----- link2-1 ----- link3-2 -----
link4-3 -----

• To correctly establish a GMPLS LSP from an
  ingress to an egress, a possible combination of
  GMPLS attributes is investigated.
• Simple constraint considerations for creating a
  LSP
• Switching capabilities (SC) of outgoing links
  from the ingress and egress nodes must be
  consistent with each other
• SC of all transit links should be consistent with
  the switching type of a LSP to be created.
• Encoding-types of all transit links should be
  consistent with the encoding type of a LSP to be
  created.

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Changes in 02/03 version

• Multiple matches of an encoding-type were
  incorporated considering hierarchy.
• An encoding-type may have multiple matches on
  transit TE links
• Ex.)
• LSP encoding (switching type) Transit link
  encoding
• --------------------------------------------------
  -------------------------------------------
• SONET/SDH (TDM) SONET/SDH
• SONET/SDH (LSC, FSC) SONET/SDH, Lambda, Fiber
• Ethernet (TDM) Ethernet, SONET/SDH
• Ethernet (LSC, FSC) Ethernet, Lambda, Fiber
• Lambda (LSC, FSC) Lambda, Fiber
• Fiber (FSC) Fiber
• Packet (PSC) Packet
• A FA-LSP may be used for the hierarchical
  consideration of SC
• New co-author Rajiv Papneja (Isocore)

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Further issues questions

• We would like to cover all possible cases to
  create a concrete guideline of CSPF path
  computation in terms of GMPLS attributes.
• In -03 version, some cases were found to be
  missing.
• Any feedback would be greatly appreciated.
• Is this draft categorized as whether BCP or
  specification?
• Since it is not enough information to categorized
  as BCP (practice!), it should be treated as
  specification.