Date: Thu, 13 Jan 2005 20:12:55 +0100 From: Lars Eggert <lars.eggert@netlab.nec.de> To: Julian Elischer <julian@elischer.org> Cc: net@freebsd.org Subject: Re: TCP out-of-order packets. Message-ID: <41E6C837.1020503@netlab.nec.de> In-Reply-To: <41E6C564.50005@elischer.org> References: <41E5C9D8.4090209@elischer.org> <20050113055111.GA11141@odin.ac.hmc.edu> <41E6C564.50005@elischer.org>
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This is a cryptographically signed message in MIME format. --------------ms070605090401070409060605 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit >>> I have a link which is provided by someone else that is 7 x E1s >>> aggregated. At leat it looks that way to me when I get to see it. >>> however I have only been able to get 60kB.sec across this, >>> despite having a tcp window size of 131072 bytes.. After >>> investigation it appears that the link is massively re-orderring >>> packets. groups of upto 10 packets may appear in random order. >>> (Maybe more, bu tI have seen 10) >>> >>> in fact packets are rarely IN order. >>> This plays havoc with the tcp sessions. A gap or jump in the ACK stream looks to TCP like a loss, no matter that it's caused by reordering. Multiple such things per window look like multiple losses and trigger a slow start under Reno. TCP/SACK should be more robust against reorderings (up to a degree, at least.) Does 4.x have the SACK code yet? What sort of link multiplexer is this? Decent ones jump through all sorts of hoops to try and reestablish the original packet order. Lars -- Lars Eggert NEC Network Laboratories --------------ms070605090401070409060605 Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIJpzCC Ay4wggKXoAMCAQICAwyFWjANBgkqhkiG9w0BAQQFADBiMQswCQYDVQQGEwJaQTElMCMGA1UE ChMcVGhhd3RlIENvbnN1bHRpbmcgKFB0eSkgTHRkLjEsMCoGA1UEAxMjVGhhd3RlIFBlcnNv bmFsIEZyZWVtYWlsIElzc3VpbmcgQ0EwHhcNMDQwNjE3MDcyMjAzWhcNMDUwNjE3MDcyMjAz WjCBhDEPMA0GA1UEBBMGRWdnZXJ0MQ0wCwYDVQQqEwRMYXJzMRQwEgYDVQQDEwtMYXJzIEVn Z2VydDEoMCYGCSqGSIb3DQEJARYZbGFycy5lZ2dlcnRAbmV0bGFiLm5lYy5kZTEiMCAGCSqG SIb3DQEJARYTbGFycy5lZ2dlcnRAZ214Lm5ldDCCASIwDQYJKoZIhvcNAQEBBQADggEPADCC AQoCggEBAOowMZjwQREXIdWxQacJDyqczykKpfIVmid2m8xBuUO53uWgnK3F8R20u/7PVugU zjNNqaivnU6qHtr/jdAn1UnyXzA/4Re+AqsKNiw8hZkVonkJ+G4O0TFzMNeWUdrjX1FaSAsL uAPA6661cN4YDzrOYC3O3zgGtVvJAra0+iw9eD2qWsnH0AVLFtq7H5ZFhz5zeOeCrrayqEhf S6tnTSjBzaH8SOdeemPTxdLRbMptLSy7lEFo8f1xisltw2eRT0txoUCqq0mjFEp8LgJ+s6p1 4M4cG3CDkKd5kNjdTWaokAo4qmpfF9IyA7uheaAHAz8UOH5GsH+Vkjbz5yFO1SsCAwEAAaNL MEkwOQYDVR0RBDIwMIEZbGFycy5lZ2dlcnRAbmV0bGFiLm5lYy5kZYETbGFycy5lZ2dlcnRA Z214Lm5ldDAMBgNVHRMBAf8EAjAAMA0GCSqGSIb3DQEBBAUAA4GBAE9rOnUtJERYLNbDztLI sH4AolAWkvNKoj7Ikst1M1X3myXqxYAHa9bsoPJy15qEV2B4ftOmJLrZL9kb8RZnzGBii8a/ XQ5wqaHZAJYcxQ6lp6UDTabhQN7J1trAOKgs+PFlF3lm6NOkXygiQH5PPO5kIHRjNvXpNGYe C7S3K8YsMIIDLjCCApegAwIBAgIDDIVaMA0GCSqGSIb3DQEBBAUAMGIxCzAJBgNVBAYTAlpB MSUwIwYDVQQKExxUaGF3dGUgQ29uc3VsdGluZyAoUHR5KSBMdGQuMSwwKgYDVQQDEyNUaGF3 dGUgUGVyc29uYWwgRnJlZW1haWwgSXNzdWluZyBDQTAeFw0wNDA2MTcwNzIyMDNaFw0wNTA2 MTcwNzIyMDNaMIGEMQ8wDQYDVQQEEwZFZ2dlcnQxDTALBgNVBCoTBExhcnMxFDASBgNVBAMT C0xhcnMgRWdnZXJ0MSgwJgYJKoZIhvcNAQkBFhlsYXJzLmVnZ2VydEBuZXRsYWIubmVjLmRl MSIwIAYJKoZIhvcNAQkBFhNsYXJzLmVnZ2VydEBnbXgubmV0MIIBIjANBgkqhkiG9w0BAQEF AAOCAQ8AMIIBCgKCAQEA6jAxmPBBERch1bFBpwkPKpzPKQql8hWaJ3abzEG5Q7ne5aCcrcXx HbS7/s9W6BTOM02pqK+dTqoe2v+N0CfVSfJfMD/hF74Cqwo2LDyFmRWieQn4bg7RMXMw15ZR 2uNfUVpICwu4A8DrrrVw3hgPOs5gLc7fOAa1W8kCtrT6LD14PapaycfQBUsW2rsflkWHPnN4 54KutrKoSF9Lq2dNKMHNofxI5156Y9PF0tFsym0tLLuUQWjx/XGKyW3DZ5FPS3GhQKqrSaMU SnwuAn6zqnXgzhwbcIOQp3mQ2N1NZqiQCjiqal8X0jIDu6F5oAcDPxQ4fkawf5WSNvPnIU7V KwIDAQABo0swSTA5BgNVHREEMjAwgRlsYXJzLmVnZ2VydEBuZXRsYWIubmVjLmRlgRNsYXJz LmVnZ2VydEBnbXgubmV0MAwGA1UdEwEB/wQCMAAwDQYJKoZIhvcNAQEEBQADgYEAT2s6dS0k RFgs1sPO0siwfgCiUBaS80qiPsiSy3UzVfebJerFgAdr1uyg8nLXmoRXYHh+06Ykutkv2Rvx FmfMYGKLxr9dDnCpodkAlhzFDqWnpQNNpuFA3snW2sA4qCz48WUXeWbo06RfKCJAfk887mQg dGM29ek0Zh4LtLcrxiwwggM/MIICqKADAgECAgENMA0GCSqGSIb3DQEBBQUAMIHRMQswCQYD VQQGEwJaQTEVMBMGA1UECBMMV2VzdGVybiBDYXBlMRIwEAYDVQQHEwlDYXBlIFRvd24xGjAY BgNVBAoTEVRoYXd0ZSBDb25zdWx0aW5nMSgwJgYDVQQLEx9DZXJ0aWZpY2F0aW9uIFNlcnZp Y2VzIERpdmlzaW9uMSQwIgYDVQQDExtUaGF3dGUgUGVyc29uYWwgRnJlZW1haWwgQ0ExKzAp BgkqhkiG9w0BCQEWHHBlcnNvbmFsLWZyZWVtYWlsQHRoYXd0ZS5jb20wHhcNMDMwNzE3MDAw MDAwWhcNMTMwNzE2MjM1OTU5WjBiMQswCQYDVQQGEwJaQTElMCMGA1UEChMcVGhhd3RlIENv bnN1bHRpbmcgKFB0eSkgTHRkLjEsMCoGA1UEAxMjVGhhd3RlIFBlcnNvbmFsIEZyZWVtYWls IElzc3VpbmcgQ0EwgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBAMSmPFVzVftOucqZWh5o wHUEcJ3f6f+jHuy9zfVb8hp2vX8MOmHyv1HOAdTlUAow1wJjWiyJFXCO3cnwK4Vaqj9xVsuv PAsH5/EfkTYkKhPPK9Xzgnc9A74r/rsYPge/QIACZNenprufZdHFKlSFD0gEf6e20TxhBEAe ZBlyYLf7AgMBAAGjgZQwgZEwEgYDVR0TAQH/BAgwBgEB/wIBADBDBgNVHR8EPDA6MDigNqA0 hjJodHRwOi8vY3JsLnRoYXd0ZS5jb20vVGhhd3RlUGVyc29uYWxGcmVlbWFpbENBLmNybDAL BgNVHQ8EBAMCAQYwKQYDVR0RBCIwIKQeMBwxGjAYBgNVBAMTEVByaXZhdGVMYWJlbDItMTM4 MA0GCSqGSIb3DQEBBQUAA4GBAEiM0VCD6gsuzA2jZqxnD3+vrL7CF6FDlpSdf0whuPg2H6ot nzYvwPQcUCCTcDz9reFhYsPZOhl+hLGZGwDFGguCdJ4lUJRix9sncVcljd2pnDmOjCBPZV+V 2vf3h9bGCE6u9uo05RAaWzVNd+NWIXiC3CEZNd4ksdMdRv9dX2VPMYIDOzCCAzcCAQEwaTBi MQswCQYDVQQGEwJaQTElMCMGA1UEChMcVGhhd3RlIENvbnN1bHRpbmcgKFB0eSkgTHRkLjEs MCoGA1UEAxMjVGhhd3RlIFBlcnNvbmFsIEZyZWVtYWlsIElzc3VpbmcgQ0ECAwyFWjAJBgUr DgMCGgUAoIIBpzAYBgkqhkiG9w0BCQMxCwYJKoZIhvcNAQcBMBwGCSqGSIb3DQEJBTEPFw0w NTAxMTMxOTEyNTVaMCMGCSqGSIb3DQEJBDEWBBRMRoBzxh1zcCjTnm7KuznSZPAhWjBSBgkq hkiG9w0BCQ8xRTBDMAoGCCqGSIb3DQMHMA4GCCqGSIb3DQMCAgIAgDANBggqhkiG9w0DAgIB QDAHBgUrDgMCBzANBggqhkiG9w0DAgIBKDB4BgkrBgEEAYI3EAQxazBpMGIxCzAJBgNVBAYT AlpBMSUwIwYDVQQKExxUaGF3dGUgQ29uc3VsdGluZyAoUHR5KSBMdGQuMSwwKgYDVQQDEyNU aGF3dGUgUGVyc29uYWwgRnJlZW1haWwgSXNzdWluZyBDQQIDDIVaMHoGCyqGSIb3DQEJEAIL MWugaTBiMQswCQYDVQQGEwJaQTElMCMGA1UEChMcVGhhd3RlIENvbnN1bHRpbmcgKFB0eSkg THRkLjEsMCoGA1UEAxMjVGhhd3RlIFBlcnNvbmFsIEZyZWVtYWlsIElzc3VpbmcgQ0ECAwyF WjANBgkqhkiG9w0BAQEFAASCAQCaHGrDQ0r24m2/C05B99GGR8xPdAyOhBn/vru+RzF20N3x jxZJmZkZO83LQrQ0mgz1hsQDbL/sXt+qTztPyOpZ/OlxarHGjgDmOO/s6DJ8lfDPM/1MhbsE tbgjoAIsVW6u60j4Ekt0w0r9uQAWyFYLJDmWSBMxO9BpVgGVBIiroZbNpYPyKvyyaSIH43yH Y+GNOukbGF9VaHteCp/y+6qnbp8znjWCCojLy7T6LRUhaDjGV0fvQUD+mcVOyseHRGXYkT82 K0dyf12kF83SBuBMO30DCYem/i4kN7W9z0euKQDlTBR8jwpZa1pY4sk8c1gow4DkMBLwQ4sf FlykjH+kAAAAAAAA --------------ms070605090401070409060605--
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