1. ForCES Forwarding Element Functional Model Lily Yang Intel Corp. Nov 18, 2002 55 rd IETF meeting

2. draft-yang-forces-model-01 Co-Authors: –Lily Yang (Intel), –Joel Halpern, –Ram Gopal (Nokia), –Ram Dantu (U. of Texas) History: –53 rd IETF (Minneapolis): contribution & presentation by Ram Gopal –54 th IETF (Yokohama): joint work (v00) –Before 55 th IETF: v01

3. Overview Motivation of the model What is in the model Open Issues & Next Steps

4. Motivation CE FE capability: what FE can be FE state: what FE is now FE configuration: what FE should be FE FE Functional Model

5. FE Block FE Block = Abstract Base Class for FE logical functions An FE block specifies: –Block ID or name (functional type) –Textual description of the function Need a namespace: –Extensible (to allow new functions added later)

6. Block Library Requirements to support 8 categories of FE functions: –Forwarding –QoS –Filtering –Port –Security –High touch –Off-loaded –Vendor specific

7. Example of FE blocks Classifiers (from DiffServ Model) Classifier Match filter-1 Match filter-2 others output3 output2 output1 input

8. FE stage & Directed Graph FE Stage: an instance of an FE block in a data path –Stage id (unique within the FE) –Block Name or ID –Number of downstream stages –List of downstream stage IDs FE Directed Graph: –Interconnection of the FE stages

9. Two approaches in graph modeling Topological approach (DiffServ model) –No explicit info carried forward beyond next stage –Fan-out function (e.g., classifier): N branches Encoded state approach (QDDIM model) –Explicit info (preamble) can be appended and carried forward to any subsequent stages –Less branches in the graph

10. Open Issues/Remaining Work Data modeling language: representation –Over the wire (transport format) –On the paper (specification language) –Candidates : SMI/SPPI/ASN.1/XML/UML Topological versus Encoded State approach Modeling of the actual functions –Identify the minimum set of functions –Work on model for each one

11. Next Steps WG document? Data modeling language: evaluation can be done in conjunction with protocol proposals Resolve on the approach (topology/state) Define a small set of functions for initial modeling Functional modeling for each

12. Questions?