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Forwarding and Control Element Separation (forces) (WG)

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Routing Area Area Director(s):

Routing Area Advisor

Technical Advisor(s)

Meeting Slides:

Blue Sheets:


Request for Comments:

Charter (as of 2013-05-17):

The ForCES working group has created a framework, requirements, a solution
protocol, a logical function block library, and other associated documents in
support of Forwarding and Control Element Separation.

Drawing on the experience gained from developing the standards and from
many efforts using this architecture, the ForCES working group is now
working on a set of additions to the model, the protocol, and the libraries.

The following 5 work items are the chartered tasks of this working group:

o Extensions to Model and Protocol

This work is to address a set of extensions to the base model and protocol
resulting in updates to RFCs 5810 and 5812. This effort will produce 2
Standards Track documents (one for the model and another for the protocol).

The model extensions will:
1. Allow compound metadata
2. Allow optional default values for datatypes
3. Allow optional access-type for datatypes inside complex components
4. Define new base type: Bitmap
5. Define new events to monitor states.

The protocol extensions will:
1. Support table range query
2. Support table append
3. Define additional return codes to reduce ambiguity
4. Define data packing rule for bitmap datatype.

o Inter-FE Connectivity

ForCES processing is often spread across multiple Forwarding Elements (FEs).
The original framework identified the interface between FEs as the "Fi"
reference point. Protocol and Logical Function Block (LFB) mechanisms to
carry metadata across the Fi interface are needed. This effort will produce
a standards track document defining the protocol on the wire to address this
need, and the LFBs used to represent the Interfaces for sending and receiving
such information. It is expected that this work will draw heavily on existing
protocol and LFB definitions.

o Parallelization

An FE can implement an LFB chain with parallelization, but the currently-
defined mechanism has no means to represent when synchronization is needed,
or to allow the CE to specify where it believes such parallelism is useful.
This work item will produce a single standards track document to improve the
handling of this case.

o Subsidiary Management

Deployment experience has demonstrated the value of using ForCES to control
the Forwarding Element Manager (FEM) by creating an LFB to represent its
function using the same encoding rules as for any other LFB. This allows it
to be controlled by the same Control Element (CE). This work item assumes the
presence of an initially booted FE whose configuration could then be updated
at runtime via an FEM LFB for runtime config purposes (e.g., by adding a new
CE and its associated IP address). This work item can also be useful in
addressing control of virtual FEs where individual FEM Managers can be
addressed to control the creation, configuration, and resource assignment of
such virtual FEs within a physical FE. This work would result in a standards
track LFB FEM library RFC.

In addition to the specific work items listed above, the working group will
allow discussions and review work of how to use ForCES to model topics of
interest to Network Function Virtualization, I2RS, or OpenFlow. It is
understood that the primary responsibility for such documents lives with other
working groups, individual contributions, or other standards bodies.

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