网络报文格式

一、802.3报文RFC（1516）报文头定义HeaderFormatHeader...--------+--------+--------+MACHeader|802.{3/4/5}MAC...--------+--------+--------++--------+--------+--------+|DSAP=K1|SSAP=K1|Control|802.2LLC+--------+--------+--------++--------+--------+---------+--------+--------+|ProtocolIdorOrgCode=K2|EtherType|802.2SNAP+--------+--------+---------+--------+--------+ThetotallengthoftheLLCHeaderandtheSNAPheaderis8-octets,makingthe802.2protocoloverheadcomeoutonanniceboundary.TheK1valueis170(decimal).TheK2valueis0(zero).Thecontrolvalueis3(UnnumberedInformation).报文样例二、AH报文RFC2402IPV4加入AHBEFOREAPPLYINGAH----------------------------IPv4|origIPhdr||||(anyoptions)|TCP|Data|----------------------------AFTERAPPLYINGAH---------------------------------IPv4|origIPhdr|||||(anyoptions)|AH|TCP|Data|---------------------------------|-------authenticated-------|exceptformutablefields报文样例IPV6AH报文RFC2402BEFOREAPPLYINGAH---------------------------------------IPv6||exthdrs||||origIPhdr|ifpresent|TCP|Data|---------------------------------------AFTERAPPLYINGAH------------------------------------------------------------IPv6||hop-by-hop,dest*,||dest||||origIPhdr|routing,fragment.|AH|opt*|TCP|Data|------------------------------------------------------------|----authenticatedexceptformutablefields-----------|报文样例AH隧道报文------------------------------------------------IPv4|newIPhdr*||origIPhdr*||||(anyoptions)|AH|(anyoptions)|TCP|Data|------------------------------------------------|-authenticatedexceptformutablefields--||inthenewIPhdr|--------------------------------------------------------------IPv6||exthdrs*|||exthdrs*||||newIPhdr*|ifpresent|AH|origIPhdr*|ifpresent|TCP|Data|--------------------------------------------------------------|--authenticatedexceptformutablefieldsinnewIPhdr-|*=constructionofouterIPhdr/extensionsandmodificationofinnerIPhdr/extensionsisdiscussedbelow.样例三、L2TPRFC2661报文样例四、PPTP报文样例五、TEREDO