{"id":537,"date":"2016-09-02T15:52:52","date_gmt":"2016-09-02T15:52:52","guid":{"rendered":"5ea1649a31336092c05438df996a3e59"},"modified":"2016-09-02T15:52:52","modified_gmt":"2016-09-02T15:52:52","slug":"","status":"publish","type":"post","link":"https:\/\/www.xiaobo.li\/notes\/archives\/537","title":{"rendered":"PPTP\/L2TP over PPPoE\u7684\u6e96\u78baMTU\/MRU\u503c"},"content":{"rendered":"
\n
Ethernet MinSize = 512bit = 64 Byte<\/code><\/div>\n
Ethernet MaxSize = 1518 Byte<\/code><\/div>\n
so Ethernet IP MTU = 1518 - 18 ( 6 SRCMAC+ 6 DSTMAC+ 2 TYPE+ 4 CRC) = 1500 B<\/code><\/div>\n
so Ethernet IP TCP MSS = 1500 - 40 ( 20 IP_HEADER + 20 TCP_HEADER) = 1460 B<\/code><\/div>\n
so Ethernet IP UDP MTU\/MRU = 1500 - 28 ( 20 IP_HEADER + 8 UDP_HEADER ) = 1472 B<\/code><\/div>\n
so PPPoE MTU\/MRU = 1500 - 8 ( 6 PPPoE_SESSION + 2 PPP_HEADER ) = 1492 B<\/code><\/div>\n
so TCP over PPPoE MSS = 1492 ( PPPoE MTU\/MRU ) - 40 ( 20 IP_HEADER + 20 TCP_HEADER) = 1452<\/code><\/div>\n
so PPTP MTU\/MRU = 1500 - 56 ( 20 IP_HEADER + 20 TCP_HEADER + 12 GRE_HEADER + 4 PPP_HEADER ) = 1444 B<\/code><\/div>\n
so TCP over PPTP MSS = 1444 ( PPTP MTU\/MRU ) - 40 ( 20 IP_HEADER + 20 TCP_HEADER) = 1404<\/code><\/div>\n
so L2TP MTU\/MRU = 1500 - 40 ( 20 IP_HEADER +8 UDP_HEADER + 8 L2TP_HEADER + 4 PPP_HEADER ) = 1460 B<\/code><\/div>\n
so TCP over L2TP MSS = 1460 ( L2TP MTU\/MRU ) - 40 ( 20 IP_HEADER + 20 TCP_HEADER) = 1420 B<\/code><\/div>\n
so PPTP over PPPoE MTU\/MRU = 1492 ( PPPoE MTU\/MRU ) - 56 ( 20 IP_HEADER + 20 TCP_HEADER + 12 GRE_HEADER + 4 PPP_HEADER ) = 1436 B<\/code><\/div>\n
so PPTP over PPTP MTU\/MRU = 1444 ( PPTP MTU\/MRU ) - 56 ( 20 IP_HEADER + 20 TCP_HEADER + 12 GRE_HEADER + 4 PPP_HEADER ) = 1388 B<\/code><\/div>\n
so PPTP over L2TP MTU\/MRU = 1460 ( L2TP MTU\/MRU ) - 56 ( 20 IP_HEADER + 20 TCP_HEADER + 12 GRE_HEADER + 4 PPP_HEADER ) = 1404 B<\/code><\/div>\n
so L2TP over PPPoE MTU\/MRU = 1492 ( PPPoE MTU\/MRU ) - 40 ( 20 IP_HEADER +8 UDP_HEADER + 8 L2TP_HEADER + 4 PPP_HEADER ) = 1452 B<\/code><\/div>\n
so L2TP over PPTP MTU\/MRU = 1444 ( PPTP MTU\/MRU ) - 40 ( 20 IP_HEADER +8 UDP_HEADER + 8 L2TP_HEADER + 4 PPP_HEADER ) = 1404 B<\/code><\/div>\n
so L2TP over L2TP MTU\/MRU = 1460 ( L2TP MTU\/MRU ) - 40 ( 20 IP_HEADER +8 UDP_HEADER + 8 L2TP_HEADER + 4 PPP_HEADER ) = 1420 B<\/code><\/div>\n<\/div>\n

 <\/p>\n

PPTP over PPPoE\u7684\u6e96\u78baMTU\u503c\u662f 1436\uff0cL2TP over PPPoE\u7684\u6e96\u78baMTU\u662f1452\u3002\u5225\u4eba\u8aaa\u7684 1400 \u504f\u4fdd\u5b88\u4e86\u9ede\u3002<\/p>\n

\u5982\u679c\u4f60\u7528 ADSL \u4e0a\u7db2\uff0c\u7136\u5f8c\u7528 PPTP \u4f86\u7ffbWall\uff0c\u90a3\u9ebc\uff0c\u4f60\u5be6\u969b\u4e0a\u662f PPP \u5354\u8b70\u8dd1\u5728 TCP \u5354\u8b70\u4e0a\u518d\u8dd1\u5728 IP \u5354\u8b70\u4e0a\u518d\u8dd1\u5728
\nPPP \u5354\u8b70\u4e0a\u518d\u8dd1\u5728 IP \u5354\u8b70\u4e0a\u518d\u8dd1\u5728\u4ee5\u592a\u7db2\u5354\u8b70\u4e0a\u30021518 \u5b57\u7bc0\u7684\u6700\u5927\u4ee5\u592a\u7db2 frame\uff0c\u6263\u4f86\u6263\u53bb\uff0c\u5c31\u5269\u4e0b
\n1436\u3002\u540c\u7406L2TP\u8dd1\u5728PPP\u93c8\u8def\u4e0a\uff0c\u6263\u4f86\u6263\u53bb\u4e5f\u5c31\u53ea\u52691452B\u4e86\uff0c\u96e3\u602a\u7b46\u8005\u4e4b\u524dVPN\u4e0a\u4e0d\u53bb\u7db2\uff0c\u539f\u4f86\u662f\u5168\u628a\u6578\u64da\u5305\u4e1f\u6389\u4e86\u3002<\/p>\n

\u5982\u679c\u8b80\u8005\u770b\u660e\u767d\u4e86\u4e0a\u9762\u7684\u89e3\u91cb\uff0c\u90a3\u9ebc\u8003\u616e\u4f60\u7528 pptp \u9023\u516c\u53f8\u7684 vpn\uff0c\u516c\u53f8\u53c8 pppoe(adsl\u64a5\u865f)\uff0c\u7136\u5f8c\u4f60\u518d pptp \u4f86\u7ffb\u529f\u592b\u7db2\uff0c\u90a3\u9ebc\uff0c\u4f60\u7684 MTU \u53ea\u80fd\u8a2d\u70ba 1518-18-8-56-56=1380 \u5b57\u7bc0\u3002<\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

\n
Ethernet MinSize = 512bit = 64 Byte<\/code><\/div>\n
Ethernet MaxSize = 1518 Byte<\/code><\/div>\n
so Ethernet IP MTU = 1518 - 18 ( 6 SRCMAC+ 6 DSTMAC+ 2 TYPE+ 4 CRC) = 1500 B<\/code><\/div>\n
so Ethernet IP TCP MSS = 1500 - 40 ( 20 IP_HEADER + 20 TCP_HEADER) = 1460 B<\/code><\/div>\n
so Ethernet IP UDP MTU\/MRU = 1500 - 28 ( 20 IP_HEADER + 8 UDP_HEADER ) = 1472 B<\/code><\/div>\n
so PPPoE MTU\/MRU = 1500 - 8 ( 6 PPPoE_SESSION + 2 PPP_HEADER ) = 1492 B<\/code><\/div>\n
so TCP over PPPoE MSS = 1492 ( PPPoE MTU\/MRU ) - 40 ( 20 IP_HEADER + 20 TCP_HEADER) = 1452<\/code><\/div>\n
so PPTP MTU\/MRU = 1500 - 56 ( 20 IP_HEADER + 20 TCP_HEADER + 12 GRE_HEADER + 4 PPP_HEADER ) = 1444 B<\/code><\/div>\n
so TCP over PPTP MSS = 1444 ( PPTP MTU\/MRU ) -...<\/code><\/div>\n<\/div>\n

\u7ee7\u7eed\u9605\u8bfb →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[283],"tags":[],"class_list":["post-537","post","type-post","status-publish","format-standard","hentry","category-technologys"],"_links":{"self":[{"href":"https:\/\/www.xiaobo.li\/notes\/wp-json\/wp\/v2\/posts\/537","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.xiaobo.li\/notes\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xiaobo.li\/notes\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xiaobo.li\/notes\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xiaobo.li\/notes\/wp-json\/wp\/v2\/comments?post=537"}],"version-history":[{"count":0,"href":"https:\/\/www.xiaobo.li\/notes\/wp-json\/wp\/v2\/posts\/537\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.xiaobo.li\/notes\/wp-json\/wp\/v2\/media?parent=537"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xiaobo.li\/notes\/wp-json\/wp\/v2\/categories?post=537"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xiaobo.li\/notes\/wp-json\/wp\/v2\/tags?post=537"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}