From owner-freebsd-net@FreeBSD.ORG Wed Jun 6 21:35:14 2012 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 077EB1065672 for ; Wed, 6 Jun 2012 21:35:14 +0000 (UTC) (envelope-from alan.bryan@yahoo.com) Received: from nm12-vm6.bullet.mail.ne1.yahoo.com (nm12-vm6.bullet.mail.ne1.yahoo.com [98.138.91.105]) by mx1.freebsd.org (Postfix) with SMTP id B0F488FC0A for ; Wed, 6 Jun 2012 21:35:13 +0000 (UTC) Received: from [98.138.90.54] by nm12.bullet.mail.ne1.yahoo.com with NNFMP; 06 Jun 2012 21:35:13 -0000 Received: from [98.138.89.198] by tm7.bullet.mail.ne1.yahoo.com with NNFMP; 06 Jun 2012 21:35:13 -0000 Received: from [127.0.0.1] by omp1056.mail.ne1.yahoo.com with NNFMP; 06 Jun 2012 21:35:12 -0000 X-Yahoo-Newman-Property: ymail-5 X-Yahoo-Newman-Id: 904014.68340.bm@omp1056.mail.ne1.yahoo.com Received: (qmail 93920 invoked by uid 60001); 6 Jun 2012 21:35:11 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1339018511; bh=R9OyKu7bOF3S/U5lb2ihlPDNp+fIFCPdEPgmwTsqR1c=; h=X-YMail-OSG:Received:X-Mailer:Message-ID:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type; b=qaSKaoucTAOufbt1L36OT4R28NInDfmcxbjYgsmt/LBhas4YtvS8HtemdTEYPSr4dvw34tEAuKH8OXdUNlvyT0bFCkuT4OTL4kuQTLj0OKqrq7nqDzZY1pb2NS0Xe7mKsi4+NnfX6xM/J5CT9WmrA4snHE2TmRIu3U6ffgAV2Sc= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Mailer:Message-ID:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type; b=xqCR59fHHj2dI+vX7ODVXQOwkOMa+GhENzzvnEB9dbRJ5nqG0z8FhMTgKaAJ6BgRzF+qyFBL17v8xA0SnfuUOMaPyjML5TsKZwpH8Tp/DXhhysyJ8ztqiBQL+dWYE3LnFlESVJwKmCqiwLRGYxZcEbtNvwkp0GPkzJiL6jyU4nE=; X-YMail-OSG: w9gnw3QVM1mNerUFn58vmLtK.ZhGJBTNSNHUGd0PGXUFbUR ko9QWzd.A1PhgWJlXVZDHCqEHJjDefkH65YhCYCqG6HSDqr5pgkAt3B1OP6Q 0dTmUQUGf_vWyK3tGzvq6GxwLWWWNGNZ0elvzUYKlvi3F5KcRgPBIhdWtfis KgmMAIL_qHVF98esRy7Exf8e2G6Qqo62XvorY8p2b1LnO77JLXkVRfOpgO5G RtwYyyTNwDW9quvV8xQ3vsasiBikGlX4pKMf2PNYXC9SHfYawJy5cFaTR9JN m_bwH0IkRcg_NCA_adqo1NmOc22rDOfqk13hUY0nIoXK6avxObdnd5UVljkN 1Hg.A3Uu.ivadtEcYZGJwqxn8wkOpx207xz_6QOKSdM_6UPxgoDY.7S.HWKJ f57nT06NlwJJde1H5IxUHzlT4uqj.2w5kCeptON_gXK68g3FDkdXdWIT3u5v lvuQgkRwwDARyR6oOsiT3A8Et Received: from [108.95.48.113] by web130101.mail.mud.yahoo.com via HTTP; Wed, 06 Jun 2012 14:35:11 PDT X-Mailer: YahooMailWebService/0.8.118.349524 Message-ID: <1339018511.22423.YahooMailNeo@web130101.mail.mud.yahoo.com> Date: Wed, 6 Jun 2012 14:35:11 -0700 (PDT) From: alan bryan To: "freebsd-net@freebsd.org" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: Slow transfers at higher latencies with high BW - RFC 1323 related? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: alan bryan List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Jun 2012 21:35:14 -0000 (also posted to FreeBSD forums) I think I may be having an issue with window scaling (RFC 1323) and am hoping that someone can enlighten me on what's going on. Server: FreeBSD 9, apache22, serving a static 100MB zip file. 192.168.18.30 Client: Mac OS X 10.6, Firefox 192.168.17.47 Network: Only a switch between them - the subnet is 192.168.16/22 Questions: #1: Does this look normal? #2: Is packet #2 specifying a window size of 65535 and a scale of 512? #3: Is packet #5 then shrinking the window size so it can use the 512 scale and still keep the overall calculated window size near 64K? #4: Why is the scale so high? Here's the first 6 packets from wireshark. For packets 5 & 6 I've included the details showing the window size and scaling factor being used for the data transfer. No. Time Source Destination Protocol Length Info 108 6.699922 192.168.17.47 192.168.18.30 TCP 78 49190 > http [SYN] Seq=0 Win=65535 Len=0 MSS=1460 WS=8 TSval=945617489 TSecr=0 SACK_PERM=1 115 6.781971 192.168.18.30 192.168.17.47 TCP 74 http > 49190 [SYN, ACK] Seq=0 Ack=1 Win=65535 Len=0 MSS=1460 WS=512 SACK_PERM=1 TSval=2617517338 TSecr=945617489 116 6.782218 192.168.17.47 192.168.18.30 TCP 66 49190 > http [ACK] Seq=1 Ack=1 Win=524280 Len=0 TSval=945617490 TSecr=2617517338 117 6.782220 192.168.17.47 192.168.18.30 HTTP 490 GET /utils/speedtest/large.file.zip HTTP/1.1 118 6.867070 192.168.18.30 192.168.17.47 TCP 375 [TCP segment of a reassembled PDU] Details: Transmission Control Protocol, Src Port: http (80), Dst Port: 49190 (49190), Seq: 1, Ack: 425, Len: 309 Source port: http (80) Destination port: 49190 (49190) [Stream index: 4] Sequence number: 1 (relative sequence number) [Next sequence number: 310 (relative sequence number)] Acknowledgement number: 425 (relative ack number) Header length: 32 bytes Flags: 0x018 (PSH, ACK) Window size value: 130 [Calculated window size: 66560] [Window size scaling factor: 512] Checksum: 0xd182 [validation disabled] Options: (12 bytes) No-Operation (NOP) No-Operation (NOP) Timestamps: TSval 2617517423, TSecr 945617490 [SEQ/ACK analysis] TCP segment data (309 bytes) 119 6.867131 192.168.18.30 192.168.17.47 TCP 1514 [TCP segment of a reassembled PDU] Details: Transmission Control Protocol, Src Port: http (80), Dst Port: 49190 (49190), Seq: 310, Ack: 425, Len: 1448 Source port: http (80) Destination port: 49190 (49190) [Stream index: 4] Sequence number: 310 (relative sequence number) [Next sequence number: 1758 (relative sequence number)] Acknowledgement number: 425 (relative ack number) Header length: 32 bytes Flags: 0x010 (ACK) Window size value: 130 [Calculated window size: 66560] [Window size scaling factor: 512] Checksum: 0xe5cf [validation disabled] Options: (12 bytes) No-Operation (NOP) No-Operation (NOP) Timestamps: TSval 2617517423, TSecr 945617490 [SEQ/ACK analysis] TCP segment data (1448 bytes)