Doc.: IEEE 802.11-07/2180r0 SubmissionM. Benveniste (Avaya Labs) Some Simulation Results for...
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M. Be nveni ste ( doc.: IEEE 802.11-07/2180r0 Submission Some Simulation Results for ‘Express Forwarding’ Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802 .org/guides/bylaws/ sb -bylaws. pdf >, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair < stuart [email protected]> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have Date: 2007-07-16 Authors: Name Address Company Phone Email Mathilde Benveniste 233 Mt Airy Road Basking Ridge, NJ 07920, US Avaya Labs- Research 908-696-5206 benveniste@ieee .org Kaustubh Sinkar 233 Mt Airy Road Basking Ridge, NJ 07920, US Avaya Labs- Research 908-696-5284 [email protected] om
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Transcript of Doc.: IEEE 802.11-07/2180r0 SubmissionM. Benveniste (Avaya Labs) Some Simulation Results for...
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
Some Simulation Results for ‘Express Forwarding’
Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11.
Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802.org/guides/bylaws/sb-bylaws.pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair < [email protected]> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <[email protected]>.
Date: 2007-07-16
Authors:Name Address Company Phone Email
Mathilde Benveniste 233 Mt Airy Road
Basking Ridge, NJ 07920, US
Avaya Labs-Research 908-696-5206 [email protected]
Kaustubh Sinkar 233 Mt Airy Road
Basking Ridge, NJ 07920, US
Avaya Labs-Research 908-696-5284 [email protected]
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
Some Simulation Results for ‘Express Forwarding’ Mathilde Benveniste
Kaustubh SinkarAvaya Labs - Research
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
IntroductionIntroduction
• VoIP cannot meet QoS requirements on a wireless mesh unless there is a way to reduce delay/jitter– End-to-end delay and jitter can be too high because of multi-hop
transmissions• Delay/jitter determines the delay experienced by the end-user
receiving QoS traffic– Frames are kept in a jitter buffer on receiving device for smooth delivery
• The mesh latency/jitter allowance for traffic streams traversing the wired network is less than for traffic staying on the mesh – A target of 10 ms for maximum latency/jitter was set for top priority AC in
802.11 TGe• Reducing the worst-case delay causes all frames of a QoS traffic
stream to experience lower delay– A shorter jitter buffer is needed
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
Express Forwarding – ReviewRef Doc 11-07/415, 639
• ‘Express forwarding’ reduces the end-to-end delay of selected frames by granting forwarding nodes immediate access to the channel
• Frames qualifying for express forwarding– Time sensitive QoS [TSQ] frames – e.g. VO/VI– Frames on paths traversing more than a specified number of hops– Other
• ‘Time critical’ frames – do not yield priority to express forwarded frames; such frames are
– Top priority management frames– Top priority frames experiencing longer delay than a specified limit
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
Express Forwarding IllustrationRef Doc 11-07/415, 639
• The Duration field is set at a value longer than usual when a TSQ frame is transmitted to a forwarding node of a multi-hop path
• The forwarding nodes, 2 and 3, adjust the Duration value on the received frame by subtracting the increment when setting their NAV
• The non-forwarding neighbor nodes – e.g. 5 – sets NAV by Duration field
NAV setting at all other neighbor nodes
NAV setting at receiving node
Channel time
ACK
Value in Duration field
1 2
1-2
Frame
3 4
2-3
DT0
3-hop path 1-4
3-4
5
DTI
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
Simulation Study
Traffic
•6 flows: 3 Video and 3 VoIP flows
One flow is express forwarded:
•6-hop VoIP flow from/to Portal
Five flows are not express forwarded:
•Single-hop peer-to-peer flows
•Next-hop neighbors don’t hear one another
VOIP
VOIP
VOIP
VIDEO VIDEO VIDEO
Flow description
- VIDEO H264 flows:
Uni-directional, Frame 1464 Bytes, 1 ms inter-arrival time
- VOIP G711 flows:
Bi-directional, Frame 200 Bytes, 20 ms inter-arrival time
11b channel
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
Uplink Delay
End-to-end delay for flow node_16 -> Portal
Node_16->Portal
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
75 80 85 90 95 100 105 110 115 120
Time (sec)
ET
E D
elay
(se
c)
Express Fwd Enabled Express Fwd Disabled
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
Downlink Delay
End-to-end delay for flow Portal -> Node_16
Portal -> Node_16
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
75 80 85 90 95 100 105 110 115 120
Time (sec)
ET
E D
elay
(se
c)
Express Fwd Disabled Express Fwd Enabled
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
Delay Overview
Flow
Traffic Type
E-to-E Delay (ms)
Express ForwardingEnabled P-N_16
Express ForwardingDisabled P-N_16
node_2 -> node_1
Video 4 3
node_5 -> node_3
VoIP 6 6
node_6 -> node_4
Video 5 5
node_7 -> node_8
Video 20 20
node_9 <-> node_10
VoIP 2 2
Portal <-> node_16 VoIP 44 / 35 93 / 99
M. Benveniste (Avaya Labs)
doc.: IEEE 802.11-07/2180r0
Submission
Conclusions
• Express forwarding reduced end-to-end delay of the multi-hop transmission to less than half
• Neighboring transmissions did not suffer significant delay increase
• The benefit of express forwarding is substantial
