RE: 8159 bytes takes 20 ms, 8160 bytes takes 200 ms?

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From: Itjalve (itjalve_at_hotmail.com.(donotspam))
Date: 10/14/04 

Date: Wed, 13 Oct 2004 22:43:05 -0700

Thank you all for your information.
And excuse my next post.

/Itjalve

"Itjalve" wrote:

> Win2k communicating with an embedded system via a point-to-point link using
> tcp winsock. 8159 bytes (7 fragments) takes about 20 milli seconds, 8160
> bytes (8 fragments) takes about 200 milli seconds.
>
> Its looks like that win2k waits about 150 ms before ack the last, 8,
> fragment. Is this a win2k problem or is it my application that is slow?
>
> I have checked my code for delays, but I can't find any problems there, i'm
> waiting for packets and the cpu load is less than 10%.
>
> //
> this is what etheral shows, a packet with ack and push flag set, and win2k
> (192.168.125.2) waits 0.15s before sending the ack
> //
>
> No. Time Source Destination Protocol Info
> 47727 36.458361 192.168.125.1 192.168.125.2 TCP
> 5515 > 2179 [PSH, ACK] Seq=2400562144 Ack=2286139454 Win=8192 Len=304
>
> Frame 47727 (358 bytes on wire, 358 bytes captured)
> Arrival Time: Oct 13, 2004 08:13:02.001731000
> Time delta from previous packet: 0.000535000 seconds
> Time since reference or first frame: 36.458361000 seconds
> Frame Number: 47727
> Packet Length: 358 bytes
> Capture Length: 358 bytes
> Ethernet II, Src: 00:00:23:08:80:33, Dst: 00:04:76:22:89:fe
> Destination: 00:04:76:22:89:fe (00:04:76:22:89:fe)
> Source: 00:00:23:08:80:33 (00:00:23:08:80:33)
> Type: IP (0x0800)
> Internet Protocol, Src Addr: 192.168.125.1 (192.168.125.1), Dst Addr:
> 192.168.125.2 (192.168.125.2)
> Version: 4
> Header length: 20 bytes
> Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
> 0000 00.. = Differentiated Services Codepoint: Default (0x00)
> .... ..0. = ECN-Capable Transport (ECT): 0
> .... ...0 = ECN-CE: 0
> Total Length: 344
> Identification: 0x2384 (9092)
> Flags: 0x04 (Don't Fragment)
> 0... = Reserved bit: Not set
> .1.. = Don't fragment: Set
> ..0. = More fragments: Not set
> Fragment offset: 0
> Time to live: 64
> Protocol: TCP (0x06)
> Header checksum: 0x9ac7 (correct)
> Source: 192.168.125.1 (192.168.125.1)
> Destination: 192.168.125.2 (192.168.125.2)
> Transmission Control Protocol, Src Port: 5515 (5515), Dst Port: 2179 (2179),
> Seq: 2400562144, Ack: 2286139454, Len: 304
> Source port: 5515 (5515)
> Destination port: 2179 (2179)
> Sequence number: 2400562144
> Next sequence number: 2400562448
> Acknowledgement number: 2286139454
> Header length: 20 bytes
> Flags: 0x0018 (PSH, ACK)
> 0... .... = Congestion Window Reduced (CWR): Not set
> .0.. .... = ECN-Echo: Not set
> ..0. .... = Urgent: Not set
> ...1 .... = Acknowledgment: Set
> .... 1... = Push: Set
> .... .0.. = Reset: Not set
> .... ..0. = Syn: Not set
> .... ...0 = Fin: Not set
> Window size: 8192
> Checksum: 0x91d9 (correct)
> Data (304 bytes)
>
>
> No. Time Source Destination Protocol Info
> 47728 36.609320 192.168.125.2 192.168.125.1 TCP
> 2179 > 5515 [ACK] Seq=2286139454 Ack=2400562448 Win=17216 [CHECKSUM
> INCORRECT] Len=0
>
> Frame 47728 (54 bytes on wire, 54 bytes captured)
> Arrival Time: Oct 13, 2004 08:13:02.152690000
> Time delta from previous packet: 0.150959000 seconds
> Time since reference or first frame: 36.609320000 seconds
> Frame Number: 47728
> Packet Length: 54 bytes
> Capture Length: 54 bytes
> Ethernet II, Src: 00:04:76:22:89:fe, Dst: 00:00:23:08:80:33
> Destination: 00:00:23:08:80:33 (00:00:23:08:80:33)
> Source: 00:04:76:22:89:fe (00:04:76:22:89:fe)
> Type: IP (0x0800)
> Internet Protocol, Src Addr: 192.168.125.2 (192.168.125.2), Dst Addr:
> 192.168.125.1 (192.168.125.1)
> Version: 4
> Header length: 20 bytes
> Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
> 0000 00.. = Differentiated Services Codepoint: Default (0x00)
> .... ..0. = ECN-Capable Transport (ECT): 0
> .... ...0 = ECN-CE: 0
> Total Length: 40
> Identification: 0xf909 (63753)
> Flags: 0x04 (Don't Fragment)
> 0... = Reserved bit: Not set
> .1.. = Don't fragment: Set
> ..0. = More fragments: Not set
> Fragment offset: 0
> Time to live: 128
> Protocol: TCP (0x06)
> Header checksum: 0x0000 (incorrect, should be 0x8671)
> Source: 192.168.125.2 (192.168.125.2)
> Destination: 192.168.125.1 (192.168.125.1)
> Transmission Control Protocol, Src Port: 2179 (2179), Dst Port: 5515 (5515),
> Seq: 2286139454, Ack: 2400562448, Len: 0
> Source port: 2179 (2179)
> Destination port: 5515 (5515)
> Sequence number: 2286139454
> Acknowledgement number: 2400562448
> Header length: 20 bytes
> Flags: 0x0010 (ACK)
> 0... .... = Congestion Window Reduced (CWR): Not set
> .0.. .... = ECN-Echo: Not set
> ..0. .... = Urgent: Not set
> ...1 .... = Acknowledgment: Set
> .... 0... = Push: Not set
> .... .0.. = Reset: Not set
> .... ..0. = Syn: Not set
> .... ...0 = Fin: Not set
> Window size: 17216
> Checksum: 0x7b6f (incorrect, should be 0x5689)
>
>
>
>
>
>
>
>

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