Subject: [midcom] RE: Protocol Eval: New Conclusion text

From: "Mary Barnes" <[email-masked]>
Date: Fri, 9 Aug 2002 13:47:01 -0500

Hi all, 

Per the email wrt 2.1.1 for COPS and Megaco, the following is my new
proposed text for the Conclusion.  I've gone ahead and shown the entirety of
the new conclusion for continuity: 

The overall statistics with regards to the number of Fully Compliant,
Partially Compliant (P+ and P) and Failing Compliancy requirements for each
of the protocols is summarized in table 1. 

              T            P+           P            F        
-----------------------------------------------------------------
SNMP          19           8            0            0
RSIP          17           7            3            0
Megaco        19           5            3            0
Diameter      21           5            1            0
COPS          20           5            2            0

Table 1: Totals across all Requirements

In considering the P+ category of compliancy, an important aspect is the
mechanism for support of extensibility. The extension mechanism provided by
SNMP and COPS-PR using MIBs and PIBs respectively, provides extensions with
no impact to the protocol.  Diameter extensions require protocol changes,
thus has a higher impact, although the extensions can be handled by other
Diameter entities without being understood.  Megaco's extension mechanisms
of packages also requires protocol changes that must be understand by both
sending and receiving entities, also being considered higher impact. The
RSIP extension mechanism has the largest impact on the existing protocol and
is based upon defining the necessary new parameters.

The SNMP management framework meets all the specified MIDCOM protocol
requirements with the appropriate design of a MIDCOM MIB module. SNMP is a
proven technology with stable and proven development tools, which already
provides support for NAT configuration.  For matching the security
requirements and for the support of requirement 2.1.7, only the most recent
version, SNMPv3, is suited. Although, SNMPv3 is not as proven of a
technology as SNMPv1 and SNMPv2, the protocol specifications are more mature
and have undergone more validation than the other protocols in the
evaluation. The applicability of SNMP to the MIDCOM framework has a
restriction in that it assumes the MIDCOM PDP is part of the Middlebox.

RSIP fully meets many of the MIDCOM requirements.  In addition, RSIP
requires additions/extensions to meet several of the requirements. RSIP
would also require several framework elements to be added to the MIDCOM
framework as identified in section 1.2.3.

Megaco fully meets most of the key requirements for the MIDCOM Protocol.
Additional extensions in the form of new Termination / Package definition
(without impacting the base protocol) would be required for MIDCOM to meet
several of the requirements.  In order to meet the remaining requirements,
modeling the underlying Middlebox resources (e.g., filters, policy rules) as
separate elements from the Megaco entities might allow the usage of the
protocol as-is, satisfying some of the resource access control requirements.

The Diameter evaluation indicated a good overall fit with no requirements
failing to be met. Some partially met requirements were identified that
could be addressed by a new application extension.  However, the Diameter
architecture may be too heavy for the MIDCOM application and clearly much of
the Diameter base is not needed. In addition, Diameter is the only protocol
in the evaluation for which the RFCs are not yet published. Other than these
reservations, the protocol is a good fit to MIDCOM requirements.

The COPS evaluation indicates that the protocol meets the majority of the
MIDCOM protocol requirements by using the protocol's native extension
techniques, with COPS-PR being explicitly required to meet requirements
2.1.3 and 2.2.3. In order to fully satisfy the one partially met
requirement, 2.1.1, the COPS model would need to allow a PDP to establish
communication with a PEP. While this is not explicitly prohibited by the
COPS model, it would require additions, in the form of local policy, to
ensure the proper establishment of an authorized association. 

-----------------------------------------------
Any concerns with this proposal should be posted to the mailing list by 9am
CST on Monday, August 12th.

Regards,
Mary. 

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