SIP End-to-EndPerformance Metrics

draft-malas-performance-metrics-06.txt

Acknowledgments

• Al Morton (AT&T)

• Jean-Francois Mule (CableLabs)

• Adam Uzelac (Global Crossing)

• Carol Davids (Illinois Institute of Technology)

• Mario Delkinov (Ericcson)

• Dean Bayless, John Hearty, Rich Terpstra (Level 3)

Intro

• Industry Need Continues– Comes up over and over again– Developing SIP vs. Managing SIP– Measuring SIP performance is more critical

(visible) than ISUP (For now...)

Terminology

• Session– Request, Create, and Conclude (RFC 3261)– Measuring processes to setup sessions– Measuring signaling only

• Session Establishment– “...occurs when a 200OK response from the

UAS has been received, in response to a corresponding UAC’s INVITE setup request, indicating the session setup request was successful”

Terminology (Cont’d)

• Session Setup– “...set of messages and included parameters directly

related to the process of a UAC requesting to establish a session with a corresponding UAS.” (“..also described as a set of steps in order to establish “ringing” – RFC 3261)

• Time Begin– Changed to begin when the first bit is sent and not the

last (Based on ITU-T E.721)– Measurable at logical or physical interface

Overview Changes

• Changed - “Average" defined as one of the uses of the metric

• Removed - "all metrics calculated by inputs at UAC“

• Added methods for measuring at UAS• Added references to ASR (E.411) and PDD

(E.721)• Output vs. Input Values

– “... output values are directly related to the accuracy and the equivalent level of granularity of the input values.”

Metrics Changes

• Registration Request Delay– Output measured in milliseconds– Failures - “Many times registration attempts

are repeated; therefore, a failed scenario must identify a failure response associated with the final attempt”

• Session Request Delay– Output measured in milliseconds– Added reference to ITU-T E.721 (Post-

selection Delay)

Metrics Changes

• Session Disconnect Delay– Output measured in milliseconds

• Average Hops per INVITE– Added back in based on requests– Defines a method for capturing the number of

hops an INVITE takes as it traversing the “End-to-End” network.

Additional Considerations

• Forking– Differs based on point of measurement

• Downstream forking – who cares?• Immediate forking – utilize first INVITE or set of

INVITE’s and first 200 OK – Utilize tag

– Metric Template• Makes draft extensible• Defines what new metrics should contain in order

to be defined.

Metric Consideration

• Session Efficiency Establishment Rate (SEER)– Extension to Session Establishment Rate– Derived from E.411 “Network Effectiveness

Ratio”– Exclude the effects of customer behavior and

user agent behavior– Essentially add 480, 486, and 600 to SER

numerator– Propose this metric is included

Metric Consideration

• Initial Response Time– Metric is for the originator– Time from INVITE to the first SIP response

• Authentication Time– Isolates authentication related time– Detecting problems with second INVITE/REGISTER

to 401– Measured from first INVITE to second INVITE w/

credentials (same for REGISTER)

• Need feedback

What’s Next?

• Add in the proposed metric...

• Are use cases needed...

• IANA Considerations

• Is it done...or is it dead...

• Next steps...