{"id":1788,"date":"2023-01-09T23:55:57","date_gmt":"2023-01-09T15:55:57","guid":{"rendered":"https:\/\/blog.cauchyschwarz.com\/?p=1788"},"modified":"2023-01-09T23:56:04","modified_gmt":"2023-01-09T15:56:04","slug":"%e5%85%b3%e4%ba%8ebbr%e7%9a%84%e9%97%ae%e9%a2%98","status":"publish","type":"post","link":"https:\/\/blog.cauchyschwarz.com\/?p=1788","title":{"rendered":"\u5173\u4e8eBBR\u7684\u95ee\u9898"},"content":{"rendered":"\n

\u62e5\u585e\u7a97\u53e3<\/h2>\n\n\n\n

https:\/\/groups.google.com\/g\/bbr-dev\/c\/Fj2emRS4Wn4<\/a><\/p>\n\n\n\n

ACK suppression\/decimation\/acceleration \u53d1\u751f\u7684\u573a\u666f\uff1a<\/p>\n\n\n\n

1.\u4e2d\u95f4\u8def\u7531\u5668\u5bf9\u4e8e\u540c\u4e00\u8fde\u63a5\u6392\u961f\u7684\u591a\u4e2aTCP ACK\u53ea\u53d1\u6700\u540e\u4e00\u4e2a\uff0c\u524d\u9762\u7684\u90fd\u6254\u6389\uff0c\u8fd9\u6837\u5c31\u51cf\u5c11\u4e86ACK\u5360\u7528\u7684\u6d41\u91cf\uff1b<\/p>\n\n\n\n

2.wifi\/\u8def\u7531\u7f51\u7edc\u4e2d\uff0c\u8bbe\u5907\u4e0d\u662f\u6bcf\u65f6\u6bcf\u523b\u90fd\u53ef\u4ee5\u6536\u53d1\u6570\u636e\u7684\uff0c\u800c\u662f\u9700\u8981\u5411\u57fa\u7ad9\u7533\u8bf7\u6536\u53d1\u6570\u636e\u7684\u65f6\u95f4\u7247\uff0c\u6240\u4ee5\u8bbe\u5907\u6536\u5230\u7684ACK\u4e0d\u4e00\u5b9a\u662f\u5747\u5300\u7684\uff0c\u800c\u662f\u53ef\u80fd\u5728\u5404\u4e2a\u65f6\u95f4\u7247\u5185\u4ee5burst\u4f20\u8f93\u65b9\u5f0f\u6536\u5230\u7684\u3002<\/p>\n\n\n\n

\u603b\u4e4b\uff0cACK suppression\/decimation\/acceleration\u5176\u5b9e\u90fd\u63cf\u8ff0\u7684\u662f\u4e00\u79cdACK\u5230\u8fbe\u4e0d\u5747\u5300\uff0c\u4e0d\u8fde\u7eed\u7684\u573a\u666f\uff0c\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0bBBR\u9700\u8981\u5141\u8bb8cwnd\u5927\u4e8eBDP\u3002\u56e0\u4e3a\u8ba1\u7b97BDP\u7528\u5230\u7684RTTmin\u5176\u5b9e\u662f\u901a\u8fc7\u672a\u53d7\u5230ACK suppression\/decimation\/acceleration\u5f71\u54cd\u7684ACK\u5305\u5f97\u5230\u7684\u3002\u5982\u679cBBR\u9650\u5236cwnd\u4e3aBDP\u90a3\u4e48\u5c31\u4f1a\u5bfc\u81f4\u53d1\u9001\u53d7\u9650\uff0c\u94fe\u8def\u5229\u7528\u7387\u4e0d\u5145\u5206\u3002<\/p>\n\n\n\n

\u6240\u4ee5\uff0c\u4e3a\u4e86\u514b\u670d\u8fd9\u79cd\u95ee\u9898\uff0cBBR\u540e\u9762\u589e\u52a0\u4e86\u4e00\u4e2a\u8ba1\u7b97ack aggregation\u7684patch\uff0c\u4e3acwnd\u505a\u4e86\u4e00\u4e2a\u8865\u507f\u3002<\/p>\n\n\n\n

\u8fd9\u4e2a\u5e16\u5b50\u7684\u63d0\u95ee\u8005\u4e5f\u641e\u9519\u4e86\u4e00\u4e2a\u5730\u65b9\uff0c\u90a3\u5c31\u662fBBR\u91cc\u7684cwnd_gain\u4e00\u76f4\u90fd\u662f2(\u4e0d\u8003\u8651START_UP\uff0cPROBE_RTT\uff09\u3002\u6240\u4ee5\u76f8\u5f53\u4e8e\u6700\u5f00\u59cb\u8fd9\u4e2acwnd_gain\u4e5f\u76f8\u5f53\u4e8e\u5bf9ACK suppression\/decimation\/acceleration\u573a\u666f\u4e0b\u7684cwnd\u505a\u4e86\u8865\u507f\uff0c\u7528\u76842\u500dBDP\u800c\u4e0d\u662f1\u500dBDP\u3002BBR\u5bf9\u4f7f\u75282\u8fd9\u4e2a\u503c\u7684\u63cf\u8ff0\u662f\uff1a<\/p>\n\n\n\n

\n
The \"estimated_bdp\" term allows enough packets in flight to fully\nutilize the estimated BDP of the path, by allowing the flow to send\nat BBR.BtlBw for a duration of BBR.RTprop.  Scaling up the BDP by\ncwnd_gain, selected by the BBR state machine to be above 1.0 at all\ntimes, bounds in-flight data to a small multiple of the BDP, in order\nto handle common network and receiver pathologies, such as delayed,\nstretched, or aggregated ACKs [A15<\/a>].<\/pre>\n<\/blockquote>\n\n\n\n
TCP ACK suppression<\/a>.<\/p>\n\n\n\n
\u770b\u6837\u5b50\u662f\u4e4b\u524d\u8fd9\u4e2a\u56fa\u5b9a\u76842\u500dBDP\u4e0d\u80fd\u8986\u76d6ack suppression\/aggregaion\/decimation\u7684\u60c5\u666f\uff0c2\u500d\u7684\u503c\u53ef\u80fd\u592a\u5c0f\uff0c\u540e\u9762\u624d\u52a0\u4e86\u8ba1\u7b97ack aggregation\u7684patch\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u62e5\u585e\u7a97\u53e3 https:\/\/groups.google.com\/g\/bbr-dev\/c\/Fj2emRS4Wn4 ACK suppression\/decimation\/acceleration \u53d1\u751f\u7684\u573a\u666f...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[66,28],"class_list":["post-1788","post","type-post","status-publish","format-standard","hentry","category-10","tag-bbr","tag-28"],"_links":{"self":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1788","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1788"}],"version-history":[{"count":1,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1788\/revisions"}],"predecessor-version":[{"id":1789,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1788\/revisions\/1789"}],"wp:attachment":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1788"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1788"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1788"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}