CCAMP WG, IETF 76th, Hiroshima, Japan

draft-zhang-ccamp-gmpls-g709-framework-00.txt

Fatai Zhang (zhangfatai@huawei.com)

Dan Li (danli@huawei.com)

Jianrui Han (hanjianrui@huawei.com)

Han Li (lihan@chinamobile.com)

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

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)

•WDM:OCh[r] → OCC[r] → OCG‑n[r] → OTM‑n[r].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.

• 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

– ODUflex into ODU2, ODU3 or ODU4 multiplexing (TS =1.25Gbps) • ODUflex occupies n of the 8, 32 or 80 TS for ODU2, ODU3 or ODU4 (n <= Total TS

numbers of ODUk)

– ODU2e into ODU3 or ODU4 multiplexing (TS =1.25Gbps) • ODU2e occupies 9 of the 32 TS for ODU3 or 8 of the 32 TS for ODU4

Background: Overview of G.709 (2)

Connection Management in OTN (Typical Cases)

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

LO ODUj

ODXC ODXCPXC ODXC

OCh/OTUk OCh/OTUk

PXC

Node A Node B Node C

LO ODUj

ODXC ODXCPXC ODXC

OCh/OTUk/HO ODUk OCh/OTUk/HO ODUk

PXC

Node A Node B Node C

Case 1:Connection of LO ODUk (1)

Case 2:Connection of LO ODUk (1)

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

Connection Management in OTN (Topology Representation)

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.

ODXC ODXCPXC ODXC PXC

Node A Node B Node C

PXC ODXC

Node D

OCh/OTU3/HO ODU3

OCh/OTU1 OCh/OTU2

LO ODU2

LO ODU1

Connection Management in OTN (Example)

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)

ODXC

Node A

ODXC

Node B

ODXC

Node C

ODXC

Node D

ODXC

Node E

Link #1 Link #2 Link #3

Link #5 Link #4LO ODU0

Connection

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.

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 layerOptical 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).)

Implications for GMPLS Routing

One ODU link may support one or more types of ODU signals multiplexing.

--->The routing protocol should be extended to carry this multiplexing capability.

One type of ODUj can be multiplexed to one ODUk by different tributary slots.

---> 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

---> The routing protocol should be extended to carry this link bandwidth information in OTN networks

Implications for Auto-discovery

The two ends of an ODU link may support different TS structure.

--->Correlate 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.

--->Correlate the Supported LO ODU Signal Types (which types of LO ODU can be supported by the HO ODU link)

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.

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