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July 2004 Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Two-way CTA for TCP Application] Date Submitted: [July 9, 2004] Source: [Jinwoo Hong, Inhwan Kim, Dae-kyu Bae, Hyunah Sung] Company [Samsung Electronics] Address [416 Maetan-3Dong, Yeongtong-Gu, Suwon-City, Gyeonggi-Do, South Korea] Voice:[ ], FAX: [ ], [Bill Shvodian] Company [Freescale Semiconductor] Address [8133 Leesburg Pike, Suite 700, Vienna, VA 22182, USA] Voice:[ ], FAX: [ ], freescale.com] Re: [] Abstract: [Two-way CTA for IEEE b WPAN] Purpose: [For discussion to support Two-way CTA for IEEE b WPAN] Notice: This document has been prepared to assist the IEEE P 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 acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P Jinwoo Hong et al, Samsung Electronics
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July 2004 Two-way CTA July 2004 Jinwoo Hong et al, Samsung Electronics
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doc.: IEEE 802.15-<doc#>
<month year> doc.: IEEE <doc#> July 2004 Abstract We propose the new type of CTA named ‘two-way CTA’. In existing CTA, only src DEV can send data to the other devices. In two-way CTA, even the dest DEV of the CTA can send data to src DEV of the CTA when the src DEV doesn’t have data to send anymore. Two-way CTA is efficient for TCP streaming applications Jinwoo Hong et al, Samsung Electronics <author>, <company>
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July 2004 Problem Home network standard specifies TCP streaming as a basic service TCP application The sender can proceed its transmission after receiving ACK of TCP/IP from the receiver. Superframe duration RTT will limit maximum throughput TCP ACK Latency with one way CTAs will severely impact the speed of opening up the TCP window TCP streaming application over Using isochronous Dest DEV cannot send TCP ACK in CTA Src DEV cannot send more data before receiving TCP ACK even though the CTA is available Using asynchronous QoS for streaming application is not guaranteed. Jinwoo Hong et al, Samsung Electronics
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Maximum throughput with a 64KB max TCP window
July 2004 Maximum throughput with a 64KB max TCP window Not all TCP applications support TCP window scaling (rfc 1323) TCP baseline max window is 216 bytes Max TCP throughput for non-rfc1323 TCP at the max superframe duration with one 1-way CTA in each direction 65,536*8/.0655= 8.00 Mbps with one 2-way CTAs is 65,536*8/.001= 524 Mbps Jinwoo Hong et al, Samsung Electronics
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July 2004 Jinwoo Hong et al, Samsung Electronics
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July 2004 Jinwoo Hong et al, Samsung Electronics
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Slow start comparison (TCP throughput) with TCP window scaling
July 2004 Slow start comparison (TCP throughput) with TCP window scaling TCP window scaling (rfc1323) allows for TCP max window size of up to 230 bytes With 2 way CTA: TCP can ramp up to 1.5 Gbps in 8 ms (or 8 * TCP RTT) 192 KB TCP window required to support 1.5 Gbps With 1 way CTAs: TCP can ramp up to 1.5 Gbps in 917 ms (114 times as long) 12.3 MB TCP window (64 times as large) required to support 1.5 Gbps Assumptions: Assuming 1 ms TCP ACK latency RTT 1500 byte TCP segment 65.5 ms superframe Jinwoo Hong et al, Samsung Electronics
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Two-way CTA Definition
July 2004 Two-way CTA Definition Two-way channel time allocation Both src and dest DEVs of the CTA can send data Collision of frames is controlled by using token Only Src DEV can control token timeout Operation The src DEV initiates data transmission The src DEV passes token to the dest DEV if no more data to send The dest DEV can send data after receiving token. The dest DEV passes token to the src DEV if no more data to send Above behaviors are repeated in the CTA. Jinwoo Hong et al, Samsung Electronics
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Modification (1) July 2004 MLME-CREATE-STREAM.request ( TrgtID,
DSPSSetIndex, StreamRequestID, StreamIndex, ACKPolicy, Priority, PMCTRqType, CTAType, CTARateType, CTARateFactor, DirectionType, CTRqTU, MinNumTUs, DesiredNumTU, RequestTimeout) Name Type Valid Range Description DirectionType Enumeration ONE_WAY, TWO_WAY During the allocated channel time, only one DEV can send data frames (ONE_WAY), or both DEVs can send data frames (TWO_WAY) Jinwoo Hong et al, Samsung Electronics
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Modification (2) Channel time request block field
July 2004 Modification (2) Channel time request block field Octets:1 1 1-127 Desired number of Tus Minimum number of Tus CTRq TU Direction Type CTA rate factor CTRq control Stream index Stream request ID DSPS set Index Target ID list Num targets Channel time allocation block in CTAIE Octets:2 2 1 CTA duration CTA location Stream Index Direction Type Src ID Dest ID Jinwoo Hong et al, Samsung Electronics
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Token Frame Valid frame type values Token frame format July 2004
b5 b4 b3 Frame Type Description 000 Beacon frame 001 Immediate ACK (Imm-ACK) frame 010 Delayed ACK (Dly-ACK) frame 011 Command frame 100 Data frame 101 Token frame Reserved Header field Setting on transmission Frame type Token frame value SEC ACK policy No-ACK value Retry More data DestID SrcID of the received frame SrcID DestID of the received frame Fragmentation control 0x000000 Stream index 0x00 Jinwoo Hong et al, Samsung Electronics
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Example I: Common case … … July 2004 Src DEV Dest DEV Data No Data
Token Data No Data Token Data … Jinwoo Hong et al, Samsung Electronics
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Example II: Src Token lost
July 2004 Example II: Src Token lost Src DEV Dest DEV Data … No Data Token timeout Token Data Jinwoo Hong et al, Samsung Electronics
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Example III: Dest Token Lost & Src Token Timeout
July 2004 Example III: Dest Token Lost & Src Token Timeout Src DEV Dest DEV Data … No Data Token Token timeout Token Jinwoo Hong et al, Samsung Electronics
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