Multi-layer%20port%20support%20in%20GSMP

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Multi-layer portsupport in GSMP

• Jonathan Sadler
• Staff Eng - AdTech

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Problem Statement

• GSMP allows for switches that operate with
  multiple technologies
• However, GSMP ports are defined as single layer
• A switch may support multiple label types,
  however, each switch port can support only one
  label type.

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Problem Statement

• Cross connections between ports of different
  types allowed
• Adaptation to be used is specified in Add Branch
  message
• Add Branch is mute on what layer network the
  matrix exists in, allowing adaptation to occur on
  either side of the matrix

FR SW
FRF.5
FRF.5
ATM
ATM
ATM SW
ATM/DS3
FR/DS3
FR/DS3
ATM/DS3
DS3
DS3
DS3
DS3
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Problem Statement

• TDM networks are inherently multi-layer
• A SONET/SDH physical port may be used
  forendpoints in more layer networks
• STS-1 / VC3
• STS-3c / VC4
• STS-12c / VC4-4c
• A number of SONET/SDH layers are clients of other
  layers
• VT1.5 in STS-1 / VC11 in VC3
• VC11 in VC4
• GSMP support for TDM is dependent on being able
  to handle multi-layer ports

Multi-layer port approach needs to be defined for
GSMP
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Background

• GSMPs definition of Port is based on the
  definition of IFIndex
• Historically multi-layer capable (i.e.
  channelized) physical ports have separate
  IFIndexes for each G.805 access point potentially
  connected to an IP forwarder (RFC 2495/2496)

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Background

• GMPLS adds a new way (labels) to name the clients
  running over a lower access point
• IFIndexes now used only to name lowest access
  point of link
• Label stacks allow for describing multi-layer
  hierarchies

VC11 SW
VC11/VC4
VC11/VC4
VC4-4c SW
VC4
VC4
VC4/MS
VC4/MS
VC4-4c/MS
VC4-4c/MS
MS
MS
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Possible approaches to addingmulti-layer port
support

• Separate GSMP instance per layer network
  supported by a switch.
• Ports supporting layer network would be only
  visible to that layer network, allowing ports to
  stay single layer
• Removes ability to connect two ports supporting
  different technologies (layer networks)
• Potentially requires rework of GMPLS labels, as
  IFIndex is not necessarily in the right place
• Ex. IFIndex referring to STS-1 / VC3 access point
  instead of MS access point how should VC11
  labels be formatted

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Possible Approaches to addingmulti-layer port
support

• One GSMP instance with understanding of multiple
  layers on a port. Facilitated by
• Rework of Port Configuration Message
• Rework of layer specific messages/operations
• Port Up/Down/Dead Messages
• Port Statistics
• Loopback invocation
• Admin Operational State change
• Extension of adaptation field in Add/Move Branch
• Allow for multi-layer adaptation specification
• Also potential extension of Partitioning RFC
• Add support for partitioning at finer granularity
  than port

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Discussion