CCAMP WG, IETF 76th, Hiroshima, Japan

1
Framework for GMPLS and PCE Control of G.709
Optical Transport Networks

• CCAMP WG, IETF 76th, Hiroshima, Japan
• draft-zhang-ccamp-gmpls-g709-framework-00.txt
• Fatai Zhang (zhangfatai_at_huawei.com)
• Dan Li (danli_at_huawei.com)
• Jianrui Han (hanjianrui_at_huawei.com)
• Han Li (lihan_at_chinamobile.com)

2
Background Overview of G.709 (1)

• OTN Layer Network
• Analogue Layer OCh, OMS, OTS
• Digital layer OTUk, ODUk, OPUk
• Mapping/Multiplexing
• TDM Client signal ?LO OPU ? LO ODU ? (HO OPU ?
  HO ODU ?) OTU
• ODU0 into ODU1 multiplexing (with 1.25Gbps TS
  granularity)
• ODU0, ODU1, ODUflex into ODU2 multiplexing (with
  1.25Gbps TS granularity)
• ODU1 into ODU2 multiplexing (with 2.5Gbps TS
  granularity)
• ODU0, ODU1, ODU2, ODU2e and ODUflex into ODU3
  multiplexing
• (with 1.25Gbps TS granularity)
• ODU1, ODU2 into ODU3 multiplexing (with 2.5Gbps
  TS granularity)
• ODU0, ODU1, ODU2, ODU2e, ODU3 and ODUflex into
  ODU4 multiplexing
• (with 1.25Gbps TS granularity)
• WDMOChr ? OCCr ? OCG-nr ? OTM-nr.m ?
  OTM-n.m

Note that we would only focus on the control of
the normative things for G.709, other things like
ODU3e1 and ODU3e2 in G.sup43 will be moved to an
appendix.
3
Background Overview of G.709 (2)

• Tributary Slot allocation important for Control
  Plane
• ODU0 into ODU1, ODU2, ODU3 or ODU4 multiplexing
  (TS 1.25Gbps)
• ODU0 occupies 1 of the 2, 8, 32or 80 TS for ODU1,
  ODU2, ODU3 or ODU4
• ODU1 into ODU2, ODU3 or ODU4 multiplexing (TS
  1.25Gbps)
• ODU1 occupies 2 of the 8, 32 or 80 TS for ODU2,
  ODU3 or ODU4
• ODU1 into ODU2, ODU3 multiplexing (TS 2.5Gbps)
• ODU1 occupies 1 of the 4 or 16 TS for ODU2 or
  ODU3
• ODU2 into ODU3 or ODU4 multiplexing (TS
  1.25Gbps)
• ODU2 occupies 8 of the 32 or 80 TS for ODU3 or
  ODU4
• ODU2 into ODU3 multiplexing (TS 2.5Gbps)
• ODU2 occupies 4 of the 16 TS for ODU3
• ODU3 into ODU4 multiplexing (TS 1.25Gbps)
• ODU3 occupies 31 of the 80 TS for ODU4

4
Connection Management in OTN (Typical Cases)
LO ODUj

• LO ODU connection can be created based on the
  link resource provided by OTUk/OCh
• The LO ODU can be switched at the intermediate
  ODXC node
• LO ODU is mapped into OTU directly

OCh/OTUk
OCh/OTUk
ODXC
ODXC
PXC
ODXC
PXC
Node A
Node B
Node C
Case 1Connection of LO ODUk (1)
LO ODUj

• LO ODU connection can be created based on the
  link resource provided by HO ODU
• The LO ODU can be switched at the intermediate
  ODXC node
• LO ODU is multiplexed into HO ODU

OCh/OTUk/HO ODUk
OCh/OTUk/HO ODUk
ODXC
ODXC
PXC
ODXC
PXC
Node A
Node B
Node C
Case 2Connection of LO ODUk (1)
5
Connection Management in OTN (Topology
Representation)
LO ODU2
LO ODU1
OCh/OTU2
OCh/OTU1
OCh/OTU3/HO ODU3
ODXC
ODXC
PXC
ODXC
ODXC
PXC
PXC
Node A
Node B
Node C
Node D

• Different LO ODUk (e.g., ODUflex, ODU0, ODU1,
  ODU2, ODU3, etc.) may share the same server
  Higher ODUk.
• From the viewpoint of layer connection, a simpler
  representation is to describe the LO ODU as a
  single layer network, in which the bit rate of a
  client is a parameter. This representation shows
  a single topology containing ODU links and
  subnetworks (i.e. resources) that is shared by
  all client ODU signals.

6
Connection Management in OTN (Example)
LO ODU0 Connection
ODXC
Link 5
Link 4
Node E
Link 2
Link 1
Link 3
ODXC
ODXC
ODXC
ODXC
Node A
Node B
Node C
Node D

• The above topology containing links and matrices
• Link 1 HO ODU2/OTU2, support transport of
  either LO ODU0 and LO ODU1 via HO ODU2/OTU2,
• or LO ODU2 via OTU2
• Link 2 HO ODU3/OTU3, support transport of
  either LO ODU0, LO ODU1, LO ODU2 via HO
• ODU3/OTU3, or LO ODU3 via OTU3
• Link 3 HO ODU2/OTU2, support transport of
  either LO ODU0, LO ODU1 via HO ODU2/OTU2,
• or LO ODU2 via OTU2
• Link 4 HO ODU1/OTU1, support transport of
  either LO ODU0 via HO ODU1/OTU1,
• or LO ODU1 via OTU1
• Link 5 HO ODU1/OTU1, support transport of
  either LO ODU0 via HO ODU1/OTU1,
• or LO ODU1 via OTU1
• LO ODU Matrix A, LO ODU Matrix B, LO ODU
  Matrix C, LO ODU Matrix D, LO ODU Matrix E
• Therefore, there are two possible pathes (in red)
  for the LO ODU0 connection request (from Node A
  to Node D)

7
Implications for LSP Hierarchy with GMPLS
TE

• The path computation for LO ODU connection
  request is based on the topology of ODU layer,
  including OCh layer visibility.
• Connection request in OTN can be divided into two
  layers. One layer is OCh/OTUk/HO ODUk, the other
  is LO ODU. RFC4206 defines the mechanisms to
  accomplish creating the hierarchy of LSPs. The
  LSP management of multiple layers in OTN can
  follow the procedures defined in RFC4206 and
  related MLN drafts.
• The route path computation for WSON is in the
  scope of WSON-Frame.
• This document only considers ODU layer for LO ODU
  connection request.

8
Implications for GMPLS Signaling
Some new features for the evolutive OTN has been
introduced since RFC4328 released. RFC4328
can not support these new features

• New traffic parameters may need to be extended in
  signaling message to support
• (1)New signal types of digital wrapper layer
• Optical Channel Transport Unit (OTUk) OTU4
• Optical Channel Data Unit (ODUk)
  ODU0, ODU2e, ODU4, ODUflex
• (2)ODUflex traffic parameter
• How many tributary slots need for an ODUflex
  connection along each link depends on Bit Rate
  and Bit Rate Tolerance (BR, BRT)
• Therefore, (BR, BRT) information of an ODUflex
  conn should be included in the signaling
  End-to-End
• New label should be defined to carry the exact
  label allocation information to support
• (1)A new Tributary Slot (TS) granularity
  (i.e., 1.25 Gbps)
• (2)New multiplexing hierarchy (e.g., ODU0
  into ODU1 multiplexing, ODUj into ODU4
• (with 1,25Gbps TS granularity).)

9
Implications for GMPLS Routing

• One ODU link may support one or more types of ODU
  signals multiplexing.
• ---gtThe routing protocol should be extended to
  carry this multiplexing capability.
• One type of ODUj can be multiplexed to one ODUk
  by different tributary slots.
• ---gt The routing protocol should be extended to
  carry which TS granularity supported by the ODU
  interface
• Total bandwidth of the TE link, Unreserved
  Bandwidth of the TE link, Maximum LSP Bandwidth
  are dependent on total number of the Tributary
  Slots, the unallocated Tributary Slots and the
  maximum Tributary Slots in OTN
• ---gt The routing protocol should be extended to
  carry this link bandwidth information in OTN
  networks

10
Implications for Auto-discovery

• The two ends of an ODU link may support different
  TS structure.
• ---gtCorrelate the Granularity of the TS (two
  ends of the one link should correlate TS type)
• The switching capability of two ends of the link
  may be different, so the link capability of two
  ends should be correlate.
• ---gtCorrelate the Supported LO ODU Signal
  Types (which types of LO ODU can be supported by
  the HO ODU link)

11
Implications for PCE

• PCECP also has a desire to be extended to carry
  the new signal type and related variable
  bandwidth information when a PCC requests a path
  computation.

12
Next Steps

• Move the content of G.sup43 in an appendix
• Put reference to G.709
• Continue discussion with ITU-T
• Liaison to ITU-T SG15 when/if this work is
  adopted by CCAMP
• Refine it according to the feedback from the
  meeting or mailing list