Current Meeting Report
2.5.1 Forwarding and Control Element Separation (forces)
In addition to this official charter maintained by the IETF Secretariat, there is additional information about this working group on the Web at:
http://www.sstanamera.com/~forces -- Additional FORCES Web Page
NOTE: This charter is a snapshot of the 54th IETF Meeting in Yokohama, Japan. It may now be out-of-date.
Last Modifield: 06/05/2002
Patrick Droz <firstname.lastname@example.org>
David Putzolu <David.Putzolu@intel.com>
Routing Area Director(s):
Bill Fenner <email@example.com>
Alex Zinin <firstname.lastname@example.org>
Routing Area Advisor:
Alex Zinin <email@example.com>
General Discussion: firstname.lastname@example.org
To Subscribe: email@example.com
In Body: subscribe forces (your name)
Description of Working Group:
The emergence of off-the-shelf network processor devices that implement
the fast path or forwarding plane in network devices such as routers,
along with the appearance of a new generation of third party signaling,
routing, and other router control plane software, has created the need
for standard mechanisms to allow these components to be combined into
functional wholes. ForCES aims to define a framework and associated
mechanisms for standardizing the exchange of information between the
logically separate functionality of the control plane, including
entities such as routing protocols, admission control, and signaling,
and the forwarding plane, where per-packet activities such as packet
forwarding, queuing, and header editing occur. By defining a set
of standard mechanisms for control and forwarding separation, ForCES
will enable rapid innovation in both the control and forwarding planes.
A standard separation mechanism allows the control and forwarding
planes to innovate in parallel while maintaining interoperability.
The products of this working group will be:
o A set of requirements for mechanisms to logically
separate the control and data forwarding planes of
an IP network element (NE)
o An applicability statement for the ForCES model
o Informational RFCs as necessary documenting current
approaches to the functional model and controlled
o An architectural framework defining the entities
comprising a ForCES network element and identifying
the interactions between them.
o A description of the functional model of a
o A formal definition of the controlled objects in the
functional model of a forwarding element. This
includes IP forwarding, IntServ and DiffServ QoS. An
existing specification language shall be used for
o Specification of IP-based protocol for transport of the
controlled objects. When the control and forwarding devices
are separated beyond a single hop, ForCES will make use of an
existing RFC2914 compliant L4 protocol with adequate reliability,
security and congestion control (e.g. TCP, SCTP) for transport
The main focus area of the working group will be control and
forwarding separation for IP forwarding devices where the
control and forwarding elements are in close (same room/small
number of hops) or very close (same box/one hop) proximity. Other
scenarios will be considered but at not the main focus of the
work. The functional model of the forwarding element will include
QoS (DiffServ and IntServ) capabilities of modern networking
devices such as routers. In order to minimize the effort to
integrate forwarding elements and control elements, a mechanism
for auto discovery and capability information exchange will form
an integral part of the standardized interface.
ForCES will coordinate with other standards bodies and working
groups as appropriate. Examples of such bodies include IETF/GSMP,
IETF/Megaco, the Network Processing Forum (NPF), the Multiservice
Switching Forum (MSF), IEEE P1520, and SoftSwitch. ForCES will
review relevant protocol efforts such as GSMP and Megaco and will
extend or reuse them if appropriate. If protocol reuse is
accepted as satisfactory for fulfilling the ForCES requirements
then ForCES may recharter to adopt specific deliverables around
the selected protocol.
Goals and Milestones:
|MAY 02|| ||Submit requirements document to IESG |
|JUL 02|| ||Submit framework document to IESG |
|NOV 02|| ||Submit formal definition of controlled objects in
functional model |
|NOV 02|| ||Submit forwarding element functional model document to IESG |
|MAR 03|| ||Submit applicability statement to IESG |
|MAR 03|| ||Submit protocol selection/definition document to IESG |
No Request For Comments
Current Meeting Report
IETF 54, Yokohama, ForCES Minutes
About 80 people attending the meeting.
Agenda bashing & list of draft to be reviewed.
WG status: 2 drafts on last call
ForCES Model - Draft 0 (Joel presenting)
Individual contribution: ForCES Functional Model
Draft about ForCES models:
- How to represent models (on the wire and in the doc)?
- How complex a capabilities model?
- What Elements for the State Model?
Capabilites & State models should share representation & element
identification. Should we use a combined document / on the wire
representation (XML based?) Should we use an existing one (SMI, SPPI)
We should not build our own
Q? No opinion on which aspect is used. Instead up level the problem
that we're trying to solve by picking one of these solutions? What are
the requirements e.g. do things going on the wire must be small, easy
Q: (Margaret) Want a language that is easy to use to pass the
A: (Joel): Important for the model draft to at least have the human
readable aspect. Important to also consider it from the protocol
Q: Some people want an open model where capabilities and state info
might be exchanged over existing protocol.
A: (Joel) Don't want to mix multiple protocols here. Hope for a
consistent framework for the control protocol.
Q: (Margaret): Don't think we're at the point to define the protocols
in the WG.
Current doc calls for a simple model, however
there is now existing work on which to base a more complex
capabilities model. Framework PIB Diff. Serv. QoS PIB.
Joel: Should we go for the simple case called for in the document or
should we make use of the capabilities information of the Framework
PIB & DiffServ. PIB on our framework? How complex the capability
model should we include? What is the language to define the
Q: What do we need to define the capabilities and not the language
A: (Joel): Need to define the capabilities where we want
Need to build a good but not excessive set, DiffServ set would seem a
good starting point for QoS Also need a forwarding set (and forwarding
Q: (Sue)? How do you match the capabilities and the blocks? You have a
n x n matrix.
A: (Joel) No. Capabilities about a number of state elements.
Q: Doesn't work for the forwarding blocks, this FE link to this FE.
A: (Joel) Capabilities deal with Forwarding blocks. State model deals
with the blocks.
Q: Do we want an FE be controlled by two CE? If yes the model becomes
more complex. How does topology info between the interconnection of FE
interact with the protocol?
Q: FE wants to do mcast. FE from one block to n-blocks. CE setup the FE, mcast forwarding table.
A: (Joel) Disagreement on whether it works or not. Take if off line.
NetLink - Draft 03 (no presentation)
Will declare last call completed if no comment
Requirement document - Draft 04 (Margaret presenting)
Last call period ended on the meeting date
High availability -> CE redundancy
Include possibility for multiple protocols
Added requirements to query statistics.
Last call comments:
Support both Capability & State model
Support for failure notifications from FE
Added text for off-loaded functions
Is last call complete? Design team thinks so. Doc will be forwarded
Applicability Statement (David presenting)
3 main changes to align Applicability stmt with Req. draft
Added Purpose section
Changed CE Redundancy/Failover to align with Requirements Draft
Changed Sections on Locality, per rough consensus on list
Q: (Russ) - Draft don't say locality are that close (e.g. the room).
A: (David) Current language is that the Locality is very close (fate sharing)
David will comment on the list after checking the exact text.
Q: (Russ) Will propose some text to clarify.
Architectural framework (Lily presenting)
CE Redundancy support
FE Topology examples
Message exchange examples
Q: (Alex): Routing/Forwarding table needs to be clarified. Who does
ARP need to be specified.
Q? (Chin Choi): What kinds of messages are exchanged between FE?
A: Mostly data packets that will be routed.
Fwd & Control Element Protocol (FACT)