1. Summary
The document shepherd is Lionel Morand. The responsible Area Director is
Stephen Farrell.
This document defines a mechanism that allows Diameter nodes to indicate the
relative priority of Diameter transactions. With this information other
Diameter nodes can factor the relative priority of requests into routing and
throttling decisions. This mechanism is a solution to address throttling
requirement introduced in Diameter overload control solution [RFC7068][RFC7683].
Intended status: Standards Track
2. Review and Consensus
The document starts by introducing the problematic to solve and describes
various scenarios where the use of Diameter message priority can be useful
before describing the Diameter priority mechanism.
The mechanism defined in this document is fairly simple. It consists in
defining a new AVP, DRMP AVP, that can be included in Diameter requests and
answers to indicate the priority of the command. 16 values are defined (from 0
to 15), Priority 0 being the highest priority. This priority value is used by
Diameter nodes to determine the relative priority of the message. How to set
the priority in the messages and how to use the priority information when
making routing decisions or throttling is outside the scope of this document.
It can be defined per application or can be implementation dependent.
The proposed solution has not been implemented yet, as vendors are waiting for
IANA AVP code value assignment before implementing. However, no issues are
expected with implementation. Moreover, the solution defined in this document
have been already introduced in standard specifications defined by 3GPP. It is
therefore understood that the vendors implementing 3GPP specifications will
implement this mechanism.
The document received a large support for adoption when initiated and it has
been reviewed multiple times, with detailed comments and corrections. The
version -03 addresses the last comments received after the WGLC process. There
is a strong WG consensus on the content of this document, with a broad range of
people, including key experts.
3. Security Considerations
The Security considerations section highlights the lack of e2e protection in
Diameter. It is therefore assumed that the mechanism is used in a trusted
environment.
4. IANA considerations
The IANA considerations section is consistent with the body of the document.
All protocol extensions are associated with appropriate reservations for IANA.
5. Intellectual Property
The author and contributor have confirmed conformance with IETF IPR rules (RFCs
3979, 4879, 3669, and 5378). There are no IPR disclosures on the document.
6. ID Nits
There are two IDnits that can be handled with a rev of the document when
publishing the document;
== Unused Reference: 'RFC5226' is defined on line 680, but no explicit
reference was found in the text
== Unused Reference: 'RFC4412' is defined on line 692, but no explicit
reference was found in the text
7. Other points
The RFC 6735 defines the Diameter Priority AVPs that convey over Diameter a
specific set of priority parameters that can be part of the user profile
information retrieved by a AAA client from the AAA server. These priority
parameters are used to act on the user session managed by the Diameter client
(e.g. access sessions or SIP sessions). There are not used to indicate relative
priority of messages in the Diameter-based signaling networks. The RFC 6735 is
therefore not linked to this new document.