Subject: WG Review: Common Control and Measurement Planes (coma)

From: The IESG <[email-masked]>
Date: Mon, 20 Nov 2000 15:53:47 -0500

A new IETF working group has been proposed in the IETF.
The IESG has not made any determination as yet. 

The following Description was submitted, and is provided for
informational purposes only:

Common Control and Measurement Planes (coma)
--------------------------------------------

Current Status: Proposed Working Group

Organizational Overview

The CoMa working group coordinates the work within the IETF towards
defining a common control plane and a separate common measurement
plane for ISP and SP core tunnel technologies.   The purpose of
the group, besides specifying the common control and the common
measurement protocols, is to ensure that inputs and requirements
from the MPLS, IPO, PPVPN and TE working groups (and future ones that
may be formed on related topics) are completely taken into account, and
that those working groups (and future related others) produce results
that make best, cleanest use of the commonalities in control and the
commonalities in measurement.

Description of the Working Group:

Over the last few years the need for common control and status
protocols for representing and manipulating layer 1 and 2 resources
has become more urgent. Particularly pressing is the need to
accommodate switched optical networks where the intermediate switches,
while controllable via IP-based protocols, are transparent above the
physical layer to the data traffic flowing through them. From a
control perspective, there is the need to perform such network
engineering functions as traffic engineering, provisioning path
protection and restoration, and path preemption in a common way across
both physical and tunneled technologies.

Common measurement is Independent of the actual control regime.  It
requires the ability to report on the status and properties of he
subcomponent parts of a network (e.g.  lambdas, fibers, PVCs, switch
ports, optical cross connects) to elements such as external servers,
the routing plane, or a database, and to report on the properties and
liveness status of paths currently instantiated.

This working group will tackle the problem of creating both the common
control and common measurement planes for tunnels and phyical paths.
It will deal with the technology-independent control and measurement
aspects of traffic engineering, protection/restoration, and tunnel
operation. It will define protocol support for resource sharing and
preemption. It will ensure that the control and measurement protocols
are capable of operation both within and across administrative 
boundaries.
Both intra-domain and inter-domain scopes are important, and CoMa will
design with both scopes in mind, however the working group may determine
that intra-domain protocols require faster development than those that
cross administrative boundaries.

Specific tasks for the working group include the following:

- Define a single control protocol and a single measurement
protocol such that they are independent of each other.
This allows the measurement protocol to be used by multiple
consumers, including layer 3 routing protocols, centralized path
computation servers, and passive path and resource monitoring devices,
among others. Similarly, it allows the control protocol to use
knowledge obtained by means other than the measurement
protocol. Existing IETF protocols should be used as the basis
for both protocols to every extent possible.

- Define the control protocol and the measurement protocol such that
they support multiple tunnel and physical path technologies (e.g. O-O
and O-E-O optical switches, MPLS, GRE) using input from
technology-specific working groups such as MPLS, IPO, etc.

- Define and incorporate into the control and measurement protocols
those network resource properties that are common across
technologies. For properties which are technology-specific
(e.g. wavelength-dependent dispersion of fiber paths) give guidance to
the technology-specific group(s) for how to incorporate their
parameters into the protocols.

- Define how the properties of network resources gathered by the
measurement protocol can be distributed in layer 3 routing protocols,
such as OSPF and ISIS. This includes recommended methods for
aggregation and summarization of data as needed for
scalability.

- Define the relationship between layer 3 routing protocols
and the common control protocol for establishing and maintaining
paths.

- Using input from the TE working group, ensure that the control and
measurement protocols provide both the information and the control
functions adequate to support the traffic provisioning and engineering
operations of service providers.
- Ensure that multi-layer path protection and restoration functions
are achievable using the defined control and measurement protocols,
either separately or in combination.

- Define protocol support for path measurement and liveness
monitoring, including considerations of what the currency of the
measure data needs to be, how much overhead can be tolerated for such
measurement, and how the measurements impact various control
mechanisms (including, but not limited to the common control
protocol).

Working Group Organization

In doing this work, the WG will work closely with the following other
WGs and constituencies:

- Engage SPs to further refine service requirements from a Service
Provider perspective and to ensure that such a protocol can work
reasonably with existing management and provisioning systems.

- Jointly develop any enhancements or modifications to the traffic
engineering aspects of control plane operation with the TE working
group

- Jointly progress any IGP metrics/parameters with the ISIS and
OSPF WGs

- Accommodate technology specific input from the IPO WG, and
other tunnel technologies as needed (e.g. GRE).

In addition, The CoMA WG should ensure good communication with other
standards bodies such as the ITU-T, and interoperability forums such
as the OIF and ODSI engaged in IP/optical control plane work.  But
as is generally true with IETF working groups, formal liaison
planning will be done by the IAB, and the communications flow about
technical work will be on a technical and individual contributor
basis otherwise.