1. Resource Priority Header
draft-ietf-sip-resource-priority-05
James M Polk
Henning Schulzrinne
7 March 05
(2 weeks shy of 5 year anniversary for this effort)

2. Resource Priority Header – quick review
A means of addressing congestion in SIP elements (proxies, UAS)
does not address IP-level congestion
Gives prioritized access to proxy or UAS resources
e.g., trunk
access-controlled using SIP authentication/authorization
Priority names organized into namespaces
no globally agreed-upon ordering across namespaces
typically, each element supports only 1-2 namespaces

3. Changes from previous (-05) version
removed all the modes (strict, semi-strict and loose)
Provide semantics for the priority-queue based behavior
Articulated element specific behaviors (UAC, UAS endpoint, UAS GW, proxy...) for preemption or priority-queue namespaces
New sections on each namespace with any special behaviors that are expected
Added a Future Namespace definition section

4. Version -05 IANA Registry Table
Behaviors Namespaces dsn drsn q735 ets wps
Number of Priority-values
Reference ****** this RFC (if ever published)*****
Preemption Policy yes yes yes no no
Queue Based Policy no no no yes yes
New Error Code
...and the list goes on...
This was ugly, and everyone knew it, even me

5. Version -06 IANA Registry Table
Intended New New Error
Namespace Levels Operation Rej. code code Reference
dsn preemption no no [This RFC]
drsn preemption no no [This RFC]
q preemption no no [This RFC]
ets priority-queue no no [This RFC]
wps priority-queue no no [This RFC]
This is prettier, and everyone should see this, even me

6. Version -07 IANA Registry Table
Intended New New Error
Namespace Levels Operation warning code code Reference
dsn preemption no no [This RFC]
drsn preemption no no [This RFC]
q preemption no no [This RFC]
ets priority-queue no no [This RFC]
wps priority-queue no no [This RFC]
This is even better, and everyone should see this, even me

7. Changes going into -07 version
Version -07 will be submitted Monday, March 14th
Combined the rejection text with the error text (cleaner)
Reduced the text in each namespace section (cleaner)
Responses are no longer prioritized (doesn’t work reliably or securely)
Clarified: Unknown namespaces are ignored
Rewrote section on where multiple namespaces are used, giving further semantics
Will add a bit more introductory motivational text
Moved part of the Security Considerations section that warned of poor implementations
not that the Security Considerations section ever gets ignored by anyone... d`oh!

8. Multiple Namespaces Legend: Foo.A Bar.1 (Highest priority) Foo.B Bar.2
Foo.C Bar.3 (least priority)