Forwarding and Control Element Separation
Forwarding and Control Element Separation WG
||Forwarding and Control Element Separation
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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 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.
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.