Routing and Wavelength Assignment Information Encoding for Wavelength

Routing and Wavelength Assignment Information Encoding for Wavelength Switched Optical Networks draft-bernstein-ccamp-wson-encode-00. txt Greg Bernstein Page - 1 gregb@grotto-networking. com Grotto Networking 72 th IETF – Dublin, Ireland, July 2008

Authors/Contributors • • Greg Bernstein (Grotto Networking) Diego Caviglia (Ericsson) Ander Gavler (Acreo AB) Young Lee (Huawei) Dan Li (Huawei) Wataru Imajuku (NTT) Jonas Martensson (Acreo AB) Itaru Nishioka (NEC Corp. ) Page - 2 72 th IETF – Dublin, Ireland, July 2008

Encoding RWA Info in WSON • Encoding of RWA information – Reduce info transmission burden – Reduce path computation burden • Changes from Info Model 02. txt – Moved encodings to this document – Considered compact graph representation for computation as well as transmission. Page - 3 72 th IETF – Dublin, Ireland, July 2008

Encoding Overview • Sub-TLVs – Link Sets – Connectivity Matrix – Wavelength Sets – Port Wavelength Restrictions • Composite TLVs – Node TLV, Dynamic Node TLV – Link TLV, Dynamic Link TLV Page - 4 72 th IETF – Dublin, Ireland, July 2008

Connectivity Matrix Encoding & Representation • Criteria – Reduce amount of information to transmit (scaling of control plane) – Reduce number of (internal) nodes and links needed to represent an asymmetric WDM switch (scaling of path computation algorithms is usually in terms of # of nodes and # of links). • Techniques – Sparse matrix – Minimum cover of complete bipartite subgraphs Page - 5 72 th IETF – Dublin, Ireland, July 2008

Connectivity Matrix Encoding/Rep. (cont. ) • Approach #1 – Use sparse matrix (row compression) then could associate connectivity with link – Use M+N internal nodes (see (a)) plus a link for every non zero cij. – This method adds a number of redundant links and nodes. Page - 6 72 th IETF – Dublin, Ireland, July 2008

Connectivity Matrix Encoding/Rep. (cont. ) • Approach #2 – Find a minimum cover of complete bipartite subgraphs, i. e. , pairs of ingress/egress port groups that have complete connectivity and include every port. – Encode this list of pairs of port groups using the link set sub-TLV Example ROADM Page - 7 Encoding via minimal complete bipartite cover 72 th IETF – Dublin, Ireland, July 2008

Connectivity Matrix Encoding/Rep. (cont. ) • Approach #2 (encoding graph representation) – Given compact encoding each pair of port groups will become a node in the graph representation (a) – Extra nodes may be needed to deal with ports in more than one pair (b). – Nodes maybe combined based on resulting topology (c). ROADM Encoding via minimal complete bipartite cover Page - 8 Graph representation of ROADM using only two internal nodes and one internal link 72 th IETF – Dublin, Ireland, July 2008

Connectivity Matrix sub-TLV • Use list of port pair groups – Minimal cover of complete bipartite subgraphs – Theoretically a hard problem, but WDM switches have natural structure to be useful and only need to figure this out once. – Easy to go from encoding to minimal graph representation for computation purposes • Implication – Connectivity matrix sub-TLV is a node attribute and not a link attribute Page - 9 72 th IETF – Dublin, Ireland, July 2008

Next Steps • Adopt as Working Group Document • Resolve relationship with encodings for existing GMPLS information • Encode Wavelength Converter Pools – Interconnection structure, Converter properties, Converter Status • Finalize switch encoding – Multiple fixed and switched blocks or at most one of each. Page - 10 72 th IETF – Dublin, Ireland, July 2008