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Performance Evaluation of EF-Admit

draft-gunn-tsvwg-ef-admit-evaluation-00with updates

J. Gunn Computer Sciences Corporation

R. LichtenfelsNational Communications System

D. Garbin D. Masi Noblis

P. McGregor Nyquetek

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Outline

• Background / Motivation

• EF-ADMIT

• Scenarios/Assumptions – (updates since -00)

• Results– (updates since -00)

• Conclusions

• Next Steps

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Background / Motivation

• EF-ADMIT proposed as a new DSCP to distinguish real time traffic subject to strict CAC from real time traffic subject to weak or no CAC

• Interested in protecting ETS calls (as described in IEPREP) under severe congestion– Sustained high traffic– Extensive network failure

• ETS calls can be subject to CAC (and thus can use EF-ADMIT) even when economic concerns mean that many “normal” calls are subject to weaker (or no) CAC.

• How well can EF-ADMIT protect the ETS “strict CAC” calls when network is overloaded?

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2 EF - 2 Queue Model

Policer 1

Policer 2

EF-ADMIT: Strict CAC Voice

EF: Voice

AF1: Video

AF2: Data

BE: Data

Priority

Queue

CBWFQ

EF = Expedited Forwarding (e.g., VoIP)

AF1 = Assured Forwarding (Video)

AF2 = Assured Forwarding (signaling)

BE = Best Effort (Other Data)

CBWFQ = Class Based Weighted Fair Queuing

Line Transmission

256 Kb, 1.5 Mb, 45 Mb

Baseline

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2 EF - 1 Queue Model

Policer 1

Policer 2

EF-ADMIT: Strict CAC Voice

EF: Voice

AF1: Video

AF2: Data

BE: Data

Priority

Queue

CBWFQ

EF = Expedited Forwarding (e.g., VoIP)

AF1 = Assured Forwarding (Video)

AF2 = Assured Forwarding (signaling)

BE = Best Effort (Other Data)

CBWFQ = Class Based Weighted Fair Queuing

Line Transmission

256 Kb, 1.5 Mb, 45 Mb

Baseline

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Scenarios/Assumptions (-01 version)

• Access line speeds- 256 Kb, 1.5 Mb, 45 Mb• EF-ADMIT traffic is small compared to EF traffic (10% of base EF)• Baseline traffic mix includes EF/EF-ADMIT (Voice), AF1 (Video), AF2 (Data)

and BE (Data) – Network Control traffic modeled as AF2- and is protected by EF policing– Baseline (overall) approx 80% utilization for 256 Kb, 1.5 Mb– Baseline (overall) approx 55% utilization for 45Mbps

• 10X Overload applies to all except the EF-ADMIT and AF2 traffic • Policing

– Regular” EF policed to approx 50% of line speed, – No policing on AF and BE

• Primary Scenarios (for each speed)– 1EF, 1Q (current operation)– 2EF, 1Q– 2EF, 2Q

• Secondary Scenarios- only for higher speeds– Mix Voice and Video in the EF-ADMIT stream

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256 Kbps Results

10 calls, each getting

10 %1 call, getting

100 %

•Delay and jitter for EF not relevant because only 10% of the packets for each call get through•For EF-ADMIT, delay is better for 2Q (14 ms vs. 23 ms), jitter is about the same (50 ms) •Drop rate almost identical for 1Q and 2Q

10 calls

1 call

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1.5 Mbps Results•Delay and jitter for EF not relevant because only 15% of the packets for each call get through•For EF-ADMIT, delay and jitter are both below 10 ms, for both 1Q and 2Q•Introducing EF-ADMIT video worsens delay and jitter for both EF and EF ADMIT- slightly worse for EF-ADMIT with1Q (5ms delay, 16 ms jitter)•Drop rate almost identical for 1Q and 2Q

EF - 50 calls

EF- ADMIT -1 call

50 calls, each getting

small %1 call, getting

100 %

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45 Mbps Results•Delay and jitter for EF not relevant because only small % of the packets for each call get through•For EF-ADMIT, delay and jitter are both below 1 ms, for both 1Q and 2Q•Introducing EF-ADMIT video has little effect on delay and jitter for both EF and EF ADMIT•Drop rate almost identical for 1Q and 2Q

1000 calls, each getting

small %10 call, each getting 100%

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Conclusions• Simulation and analytical results confirm the expectations described

in draft-ietf-tsvwg-admitted-realtime-dscp-00– When EF traffic is properly policed, the EF-ADMIT traffic is protected

from the effects (dropping, delay, jitter) of a major overload of EF (and AF, etc.) traffic

– When EF traffic is properly policed, the 1Q and 2Q cases perform very similarly if all the and EF and EF-ADMIT is Voice (short packets)

– When video (long packets) traffic is introduced to the EF-ADMIT traffic, delay and jitter suffer at 1.5 Mbps- little impact at 45 Mbps

• These results demonstrate significant value in preserving EF-ADMIT

performance even when overload significant causes degradation of EF performance.

• In the context of essential network services for disaster response (as addressed in IEPREP), we conclude that EF-ADMIT can help ensure that disaster response service is assured under all circumstances.

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Next Steps• Model other arrival rate and packet size distributions, for sensitivity• Evaluate the implications of mixing voice signaling traffic with voice

bearer traffic in the same PHBs.• Address how to best to ensure video capabilities for disaster

recovery under all circumstances. • Address disaster recovery data services, particularly in terms of how

well the needs can be met by appropriate assignments within the framework of the existing AF classes.

• Corroborate the event simulation and analysis results with a prototype implementation of the model configuration in the laboratory and testing the performance for the various scenarios.

• Investigate sensitivity to variations in policing

• Thank you for comments which contributed to -01 and Next Steps– Fred Baker– Ken Carlberg