{"id":8280,"date":"2024-01-03T18:04:24","date_gmt":"2024-01-03T10:04:24","guid":{"rendered":"https:\/\/egonlin.com\/?p=8280"},"modified":"2024-05-03T11:22:24","modified_gmt":"2024-05-03T03:22:24","slug":"gre%e4%b8%8evxlan","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=8280","title":{"rendered":"GRE\u4e0eVXLAN"},"content":{"rendered":"

\u4e00 GRE<\/h1>\n

1.1 \u6982\u5ff5<\/h2>\n

GRE\u5168\u79f0\u662fGeneric Routing Encapsulation\uff0c\u662f\u4e00\u79cd\u534f\u8bae\u5c01\u88c5\u7684\u683c\u5f0f\uff0c\u5177\u4f53\u683c\u5f0f\u5185\u5bb9\u89c1\uff1ahttps:\/\/tools.ietf.org\/html\/rfc2784<\/a><\/p>\n

\u534f\u8bae\u5c01\u88c5\u6307\u7684\u662f\u7528\u4e00\u79cd\u683c\u5f0f\u7684\u534f\u8bae\u5c01\u88c5\u53e6\u4e00\u79cd\u683c\u5f0f\u7684\u534f\u8bae\u3002\u5982<\/p>\n

    \n
  1. TCP\/IP\u534f\u8bae\u53ef\u4ee5\u770b\u6210\u662f\u4e00\u79cd\u5c01\u88c5\uff1aTCP\u4f20\u8f93\u5c42\u534f\u8bae\u88ab\u7f51\u7edc\u5c42\u7684IP\u534f\u8bae\u5c01\u88c5\uff0c\u901a\u8fc7IP\u534f\u8bae\u6765\u8fdb\u884c\u4f20\u8f93\u3002\uff08\u8fd9\u79cd\u5c01\u88c5\u7684\u76ee\u7684\u4e3b\u8981\u662f\u901a\u8fc7\u5206\u5c42\u6765\u4e25\u683c\u7684\u533a\u5206\u534f\u8bae\u7684\u8bbe\u8ba1\uff0c\u4f7f\u5f97\u5177\u4f53\u7684\u534f\u8bae\u8bbe\u8ba1\u7684\u65f6\u5019\u53ef\u4ee5\u66f4\u52a0\u7684\u6e05\u6670\uff09<\/li>\n
  2. IP SAN\uff0c\u5c31\u662f\u901a\u8fc7IP\u534f\u8bae\u5c01\u88c5scsi\u534f\u8bae\uff0c\u4f7f\u5f97\u6211\u4eec\u53ef\u4ee5\u76f4\u63a5\u901a\u8fc7IP\u7f51\u7edc\u6765\u8fdb\u884c\u78c1\u76d8\u6570\u636e\u7684\u4f20\u8f93\u3002\uff08\u8fd9\u79cd\u5c01\u88c5\u4e3b\u8981\u662f\u4e3a\u4e86\u4f7f\u7528\u73b0\u6709\u7684\u8bbe\u65bd\uff0c\u65b9\u4fbf\u5382\u5546\u63a8\u5e7f\u81ea\u5df1\u7684\u4ea7\u54c1\uff0c\u540c\u65f6\u901a\u8fc7\u4e24\u79cd\u534f\u8bae\u7684\u7ed3\u5408\u4ea7\u751f\u66f4\u591a\u7684\u529f\u80fd\u3002\u5bf9\u4e8eGRE\u6765\u8bf4\uff0c\u66f4\u8d8b\u5411\u4e8e\u8fd9\u79cd\u5c01\u88c5\uff09<\/li>\n<\/ol>\n

    \u5f3a\u8c03\uff1a<\/p>\n

    1\u3001\u4f46\u51e1\u4f60\u60f3\u589e\u52a0\u4e00\u79cd\u65b0\u534f\u8bae\uff0c\u90fd\u5fc5\u987b\u6709\u7f51\u7edc\u8bbe\u5907\u6765\u8d1f\u8d23\u5c01\u5305\u89e3\u5305<\/span><\/p>\n

    2\u3001\u4e92\u8054\u7f51\u5df2\u7ecf\u6784\u5efa\u5b8c\u6bd5\uff0c\u5404\u4e2a\u7f51\u7edc\u8bbe\u5907\u80fd\u8bc6\u522b\u7684\u534f\u8bae\u90fd\u56fa\u5b9a\u4e0b\u6765\u4e86\uff0c\u4f60\u65b0\u589e\u7684\u534f\u8bae\u60f3\u8981\u88ab\u76f4\u63a5\u8bc6\u522b\u662f\u4e0d\u53ef\u80fd\u7684<\/span><\/p>\n

    \u90a3\u5982\u4f55\u80fd\u5728\u73b0\u6709\u7684\u4e92\u8054\u7f51\u4e16\u754c\u91cc\u8dd1\u6211\u4eec\u7684\u65b0\u534f\u8bae\u5305\u5462\uff1f\u7b54\u6848\u5c31\u662f\u534f\u8bae\u5c01\u88c5\uff0c\u7528\u5df2\u77e5\u7684\u3001\u53ef\u4ee5\u88ab\u8bc6\u522b\u7684\u534f\u8bae\u628a\u4f60\u7684\u65b0\u534f\u8bae\u5305\u5728\u5185\u5c42<\/span><\/p>\n

    \u7b49\u5305\u9001\u8fbe\u5bf9\u7aef\u65f6\uff0c\u518d\u7528\u4e13\u95e8\u4e13\u95e8\u4e13\u95e8\u5904\u7406\u65b0\u534f\u8bae\u7684\u7f51\u7edc\u8bbe\u5907\uff08\u53ef\u80fd\u662f\u865a\u62df\u8bbe\u5907\uff09\u6765\u89e3\u6790\u65b0\u534f\u8bae\u5373\u53ef\u3002\u53d1\u5305\u8fc7\u7a0b\u4e5f\u662f\u5982\u6b64<\/span><\/p>\n

    1.2 GRE\u5c01\u88c5\u683c\u5f0f<\/h2>\n

    GRE\u7684\u76ee\u7684\u662f\u8bbe\u8ba1\u4e00\u79cd\u901a\u7528\u7684\u5c01\u88c5\u683c\u5f0f\uff0c\u6240\u4ee5\u5982\u679c\u5c06\u5b83\u4e0e\u4e00\u4e9b\u4e3a\u7279\u5b9a\u76ee\u7684\u8fdb\u884c\u8bbe\u8ba1\u7684\u5c01\u88c5\u534f\u8bae\u6bd4\u8f83\uff0c\u90a3\u4e48GRE\u662f\u6ca1\u6709\u592a\u591a\u4f18\u52bf\u7684\u3002<\/p>\n

    A GRE encapsulated packet has the form:
    \n

    \"file\"<\/div><\/p>\n
      \n
    1. Delivery Header: \u5728GRE\u4e2d\uff0c\u9700\u8981\u88ab\u4f20\u8f93\u548c\u5c01\u88c5\u7684\u62a5\u6587\u79f0\u4e4b\u4e3apayload packet\uff0c\u800c\u7528\u4e8e\u5c01\u88c5\u548c\u4f20\u8f93\u7684\u534f\u8bae\u5219\u6210\u4e3adelivery protocol\u3002<\/li>\n<\/ol>\n
        \n
      1. GRE header: GRE\u5728\u5c01\u88c5\u7684\u65f6\u5019\uff0c\u9664\u4e86payload packet\u5916\uff0c\u4f1a\u751f\u6210\u4e00\u4e2aGRE header\u3002<\/li>\n
      2. payload packet: \u6211\u4eec\u771f\u5b9e\u8981\u53d1\u9001\u7684\u6570\u636e\u5305GRE header + payload\u4e00\u8d77\u88abdelivery\u534f\u8bae\u5c01\u88c5\u7528\u4e8e\u4f20\u8f93\uff0cGRE header\u4f1a\u5305\u542bpayload\u7684\u4e00\u4e9b\u4fe1\u606f\uff0c\u5305\u62ecchecksum\u3001version\u3001payload\u7684\u534f\u8bae\u7c7b\u578b\u7b49\u3002\u53ef\u4ee5\u770b\u5230\uff0c\u901a\u8fc7\u8fd9\u4e2aGRE header\u7684\u534f\u8bae\u7c7b\u578b\u5b57\u6bb5\uff0c\u6211\u4eec\u53ef\u4ee5\u505a\u5f88\u591a\u7684\u4e8b\u60c5\u3002\u65e2\u7136\u5e95\u5c42\u7684delivery\u534f\u8bae\u662f\u7528\u4e8e\u4f20\u8f93\u7684\uff0c\u90a3\u4e48A\u548cB\u901a\u4fe1\u7684\u65f6\u5019delivery\u534f\u8bae\u53ef\u4ee5\u770b\u6210\u662f\u4e2a\u90ae\u5c40\u9001\u4fe1\u706b\u8f66\uff0c\u867d\u7136\u5f88\u91cd\u8981\uff0c\u4f46\u662f\u5bf9\u4e8e\u4e1a\u52a1\u7406\u89e3\u6765\u8bf4\u6ca1\u6709\u5176\u8fd0\u9001\u7684\u4fe1\u91cd\u8981\u3002\u5f53\u8131\u53d6\u8fd9\u4e00\u5c42delivery\u5c42\u540e\uff0c\u6211\u4eec\u600e\u4e48\u77e5\u9053\u4fe1\u7684\u683c\u5f0f\u5462\uff1f\u901a\u8fc7GRE header\u4e2d\u7684\u534f\u8bae\u7c7b\u578b\u6211\u4eec\u5c31\u80fd\u77e5\u9053\u534f\u8bae\u7c7b\u578b\u4e86\uff0c\u65e2\u7136\u77e5\u9053\u4e86\u534f\u8bae\u7c7b\u578b\uff0c\u90a3\u4e48\u5c31\u6709\u80fd\u529b\u89e3\u6790\u4e86\u3002\u7531\u4e8eGRE\u662f\u4e00\u79cd\u901a\u7528\u7684\u683c\u5f0f\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528GRE\u8fdb\u884c\u5f88\u591a\u4e0d\u540c\u79cd\u7c7b\u7684\u5c01\u88c5\u3002\u6bd4\u5982\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528PPTP\u534f\u8bae\u6765\u8fdb\u884cVPN\uff0c\u53ef\u4ee5\u4f7f\u7528IPv4\u6765\u5305\u88f9IPv6\u3002\u6bd4\u8f83\u5e38\u89c1\u7684delivery\u534f\u8bae\u4e00\u822c\u662fIP\u534f\u8bae\u3002\u4e0d\u8fc7GRE\u5728\u8bbe\u8ba1\u7684\u65f6\u5019\u6709\u4e00\u4e2a\u95ee\u9898\uff0c\u90a3\u5c31\u662f\u6ca1\u6709\u8003\u8651\u52a0\u5bc6\u3002\u56e0\u6b64\u73b0\u5728\u5e38\u89c1\u7684\u9700\u8981\u52a0\u5bc6\u7684\u5c01\u88c5\u4e00\u822c\u662f\u7528\u7684IPsec\u534f\u8bae\u3002\u4f8b\uff1aA\u4e3b\u673a\u662f\u5728\u516c\u53f8\uff0cB\u4e3b\u673a\u662f\u5728\u5bb6\uff0cA\u7f51\u7edc\u7684\u5730\u5740\u4e3a192.168.1.1\uff0cB\u7f51\u7edc\u7684\u5730\u5740\u4e3a192.168.2.1\uff0cA\u5982\u679c\u8981\u548cB\u901a\u4fe1\uff0c\u5219\u9700\u8981\u901a\u8fc7\u4e92\u8054\u7f51\uff0c\u6240\u4ee5\u5728A\u8fde\u63a5\u7684\u8def\u7531\u5668RA\u4e0a\uff0c\u4f1a\u914d\u7f6e\u4e00\u4e2atunnel\u53e3\uff0ctunnel\u53e3\u7684\u4fe1\u606f\u662f\uff081.1.1.1 -> 2.2.2.2\uff09\uff0c\u5728B\u8fde\u63a5\u7684\u8def\u7531\u5668RB\u4e0a\u4e5f\u4f1a\u914d\u7f6e\u4e00\u4e2atunnel\u53e3\uff0ctunnel\u53e3\u7684\u4fe1\u606f\u662f\uff082.2.2.2 -> 1.1.1.1\uff09\u3002\u540c\u65f6\u5728\u8bbe\u7f6e\u597d\u8def\u7531\u7684\u60c5\u51b5\u4e0b\uff0cA\u53d1\u9001\u4e00\u4e2a\u62a5\u6587\u7ed9B\uff0c\u62a5\u6587\u4f1a\u9996\u5148\u5230RA\uff0cRA\u53d1\u73b0\u62a5\u6587\u9700\u8981\u8d70\u4e92\u8054\u7f51\uff0c\u4e8e\u662f\u901a\u8fc7tunnel\u53e3\u5c01\u88c5\uff0c\u5c01\u88c5\u7684delivery\u534f\u8bae\u7684\u76ee\u7684\u5730\u5740\u5199\u7684\u662f\u914d\u7f6e\u7684RB\u7684\u5730\u57402.2.2.2\u3002\u62a5\u6587\u5230\u4e86RB\u540edelivery\u534f\u8bae\u88ab\u8131\u53bb\uff0c\u7136\u540eRB\u6839\u636e\u8def\u7531\u4fe1\u606f\u8f6c\u53d1\u7ed9B\u3002
        \n\uff08        http:\/\/assafmuller.com\/2013\/10\/10\/gre-tunnels\/<\/a>\uff09
        \n
        \"file\"<\/div>
        \n\u5f53A\uff08192.168.1.1\uff09 ping B\uff08192.168.2.1\uff09\u65f6\uff0c\u62a5\u6587\u662f\u5982\u4e0b\u5f62\u5f0f\u7684\uff1a
        \n
        \"file\"<\/div>
        \n
        \"file\"<\/div><\/li>\n<\/ol>\n

        1.2 Neutron\u4e2d\u7684GRE
        \n\uff08        http:\/\/assafmuller.com\/2013\/10\/14\/gre-tunnels-in-openstack-neutron\/<\/a>\uff09<\/p>\n

        br-tun\u7f51\u6865\u4fe1\u606f\uff1a<\/p>\n

        [root@NextGen1 ~]# ovs-vsctl show\r\n911ff1ca-590a-4efd-a066-568fbac8c6fb\r\n[... Bridge br-int omitted ...]\r\n    Bridge br-tun\r\n        Port patch-int\r\n            Interface patch-int\r\n                type: patch\r\n                options: {peer=patch-tun}\r\n        Port br-tun\r\n            Interface br-tun\r\n                type: internal\r\n        Port \"gre-2\"\r\n            Interface \"gre-2\"\r\n                type: gre\r\n                options: {in_key=flow, local_ip=\"192.168.1.100\", out_key=flow, remote_ip=\"192.168.1.101\"}\r\n        Port \"gre-1\"\r\n            Interface \"gre-1\"\r\n                type: gre\r\n                options: {in_key=flow, local_ip=\"192.168.1.100\", out_key=flow, remote_ip=\"192.168.1.102\"}<\/code><\/pre>\n
        VM1(10.0.0.1) pings VM2(10.0.0.2) in different nodes :
        \nBefore VM1 can create an ICMP echo request message, VM1 must send out an ARP request for VM2\u2019s MAC address. A quick reminder about ARP encapsulation \u2013 It is encapsulated directly in an Ethernet frame \u2013 No IP involved (There exists a base assumption that states that ARP requests never leave a broadcast domain therefor IP packets are not needed). The Ethernet frame leaves VM1\u2019s tap device into the host\u2019s br-int. br-int, acting as a normal switch, sees that the destination MAC address in the Ethernet frame is FF:FF:FF:FF:FF:FF \u2013 The broadcast address. Because of that it floods it out all ports, including the patch cable linked to br-tun. br-tun receives the frame from the patch cable port and sees that the destination MAC address is the broadcast address. Because of that it will send the message out all GRE tunnels (Essentially flooding the message). But before that, it will encapsulate the message in a GRE header and an IP packet. In fact, two new packets are created: One from 192.168.1.100 to 192.168.1.101, and the other from 192.168.1.100 to 192.168.1.102. The encapsulation over the GRE tunnels looks like this:<\/p>\n
        \"file\"<\/div><\/p>\n
        To summarize, we can conclude that the flow logic on br-tun implements a learning switch but with a GRE twist. If the message is to a multicast, broadcast, or unknown unicast address it is forwarded out all GRE tunnels. Otherwise if it learned the destination MAC address via earlier messages (By observing the source MAC address, tunnel ID and incoming GRE port) then it forwards it to the correct GRE tunnel.<\/p>\n
        br-tun\u6d41\u8868\uff1a<\/p>\n
        [root@NextGen1 ~]# ovs-ofctl dump-flows br-tun\r\nNXST_FLOW reply (xid=0x4):\r\n cookie=0x0, duration=182369.287s, table=0, n_packets=5996, n_bytes=1481720, idle_age=52, hard_age=65534, priority=1,in_port=3 actions=resubmit(,2)\r\n cookie=0x0, duration=182374.574s, table=0, n_packets=14172, n_bytes=3908726, idle_age=5, hard_age=65534, priority=1,in_port=1 actions=resubmit(,1)\r\n cookie=0x0, duration=182370.094s, table=0, n_packets=0, n_bytes=0, idle_age=65534, hard_age=65534, priority=1,in_port=2 actions=resubmit(,2)\r\n cookie=0x0, duration=182374.078s, table=0, n_packets=3, n_bytes=230, idle_age=65534, hard_age=65534, priority=0 actions=drop\r\n cookie=0x0, duration=182373.435s, table=1, n_packets=3917, n_bytes=797884, idle_age=52, hard_age=65534, priority=0,dl_dst=00:00:00:00:00:00\/01:00:00:00:00:00 actions=resubmit(,20)\r\n cookie=0x0, duration=182372.888s, table=1, n_packets=10255, n_bytes=3110842, idle_age=5, hard_age=65534, priority=0,dl_dst=01:00:00:00:00:00\/01:00:00:00:00:00 actions=resubmit(,21)\r\n cookie=0x0, duration=182103.664s, table=2, n_packets=5982, n_bytes=1479916, idle_age=52, hard_age=65534, priority=1,tun_id=0x1388 actions=mod_vlan_vid:1,resubmit(,10)\r\n cookie=0x0, duration=182372.476s, table=2, n_packets=14, n_bytes=1804, idle_age=65534, hard_age=65534, priority=0 actions=drop\r\n cookie=0x0, duration=182372.099s, table=3, n_packets=0, n_bytes=0, idle_age=65534, hard_age=65534, priority=0 actions=drop\r\n cookie=0x0, duration=182371.777s, table=10, n_packets=5982, n_bytes=1479916, idle_age=52, hard_age=65534, priority=1 actions=learn(table=20,hard_timeout=300,priority=1,NXM_OF_VLAN_TCI[0..11],NXM_OF_ETH_DST[]=NXM_OF_ETH_SRC[],load:0->NXM_OF_VLAN_TCI[],load:NXM_NX_TUN_ID[]->NXM_NX_TUN_ID[],output:NXM_OF_IN_PORT[]),output:1\r\n cookie=0x0, duration=116255.067s, table=20, n_packets=3917, n_bytes=797884, hard_timeout=300, idle_age=52, hard_age=52, priority=1,vlan_tci=0x0001\/0x0fff,dl_dst=fa:16:3e:1f:19:55 actions=load:0->NXM_OF_VLAN_TCI[],load:0x1388->NXM_NX_TUN_ID[],output:3\r\n cookie=0x0, duration=182371.623s, table=20, n_packets=0, n_bytes=0, idle_age=65534, hard_age=65534, priority=0 actions=resubmit(,21)\r\n cookie=0x0, duration=182103.777s, table=21, n_packets=10235, n_bytes=3109310, idle_age=5, hard_age=65534, priority=1,dl_vlan=1 actions=strip_vlan,set_tunnel:0x1388,output:3,output:2\r\n cookie=0x0, duration=182371.507s, table=21, n_packets=20, n_bytes=1532, idle_age=65534, hard_age=65534, priority=0 actions=drop<\/code><\/pre>\n
        table\u8868\u6d41\u7a0b
        \n
        \"file\"<\/div>
        \n\u5728openstack\u4e2d\u4e3b\u8981\u662f\u901a\u8fc7ovs\uff0covs\u652f\u6301GRE\u3002\u901a\u8fc7GRE\uff0cVM\u4e4b\u95f4\u7684ARP\u3001IP\u62a5\u6587\u90fd\u80fd\u5728GRE\u7684\u5c01\u88c5\u4e0b\u901a\u8fc7IP\u7f51\u7edc\u8fdb\u884c\u4f20\u9012\u3002\u4e0d\u540c\u7684\u7f51\u7edc\u901a\u8fc7GRE header\u4e2d\u7684tunnel id\u53f7\u533a\u522b\u3002\u7531\u4e8eovs\u652f\u6301openflow\u534f\u8bae\uff0c\u4e3a\u4e86\u6548\u7387\u548c\u6027\u80fd\uff0cmac\u548cGRE\u7684\u8def\u7531\u5173\u7cfb\u4f1a\u5b58\u653e\u5728ovs\u7684\u6d41\u8868\u4e2d\u3002\u4ece\u94fe\u63a5\u4e2d\u7684\u6587\u7ae0\u53ef\u4ee5\u770b\u51fa\uff0cGRE\u6709\u4e00\u4e2a\u7f3a\u70b9\uff0c\u90a3\u5c31\u662f\u6bcf\u65b0\u589e\u4e00\u4e2a\u8ba1\u7b97\u8282\u70b9\uff0c\u90fd\u9700\u8981\u5176\u548c\u6240\u6709\u5176\u4ed6\u8ba1\u7b97\u8282\u70b9\u4ee5\u53canetwork\u63a7\u5236\u5668\u5efa\u7acbGRE\u94fe\u63a5\u3002\u5728\u8ba1\u7b97\u8282\u70b9\u5f88\u591a\u7684\u65f6\u5019\u4f1a\u6709\u6027\u80fd\u95ee\u9898\u3002
        \nGRE \u6280\u672f\u672c\u8eab\u8fd8\u662f\u5b58\u5728\u4e00\u4e9b\u4e0d\u8db3\u4e4b\u5904\uff1a<\/p>\n
        \uff081\uff09Tunnel \u7684\u6570\u91cf\u95ee\u9898<\/p>\n
        GRE \u662f\u4e00\u79cd\u70b9\u5bf9\u70b9\uff08point to point\uff09\u6807\u51c6\u3002Neutron \u4e2d\uff0c\u6240\u6709\u8ba1\u7b97\u548c\u7f51\u7edc\u8282\u70b9\u4e4b\u95f4\u90fd\u4f1a\u5efa\u7acb GRE Tunnel\u3002\u5f53\u8282\u70b9\u4e0d\u591a\u7684\u65f6\u5019\uff0c\u8fd9\u79cd\u7ec4\u7f51\u65b9\u6cd5\u6ca1\u4ec0\u4e48\u95ee\u9898\u3002\u4f46\u662f\uff0c\u5f53\u4f60\u5728\u4f60\u7684\u5f88\u5927\u7684\u6570\u636e\u4e2d\u5fc3\u4e2d\u6709 40000 \u4e2a\u8282\u70b9\u7684\u65f6\u5019\uff0c\u53c8\u4f1a\u662f\u600e\u6837\u4e00\u79cd\u60c5\u5f62\u5462\uff1f\u4f7f\u7528\u6807\u51c6 GRE\u7684\u8bdd\uff0c\u5c06\u4f1a\u6709 780 millions \u4e2a tunnels\u3002<\/code><\/pre>\n
        \uff082\uff09\u6269\u5927\u7684\u5e7f\u64ad\u57df<\/p>\n
        GRE \u4e0d\u652f\u6301\u7ec4\u64ad\uff0c\u56e0\u6b64\u4e00\u4e2a\u7f51\u7edc\uff08\u540c\u4e00\u4e2a GRE Tunnel ID\uff09\u4e2d\u7684\u4e00\u4e2a\u865a\u673a\u53d1\u51fa\u4e00\u4e2a\u5e7f\u64ad\u5e27\u540e\uff0cGRE \u4f1a\u5c06\u5176\u5e7f\u64ad\u5230\u6240\u6709\u4e0e\u8be5\u8282\u70b9\u6709\u96a7\u9053\u8fde\u63a5\u7684\u8282\u70b9\u3002<\/p>\n
        \uff083\uff09GRE \u5c01\u88c5\u7684IP\u5305\u7684\u8fc7\u6ee4\u548c\u8d1f\u8f7d\u5747\u8861\u95ee\u9898<\/p>\n
        \u76ee\u524d\u8fd8\u662f\u6709\u5f88\u591a\u7684\u9632\u706b\u5899\u548c\u4e09\u5c42\u7f51\u7edc\u8bbe\u5907\u65e0\u6cd5\u89e3\u6790 GRE Header\uff0c\u56e0\u6b64\u5b83\u4eec\u65e0\u6cd5\u5bf9 GRE \u5c01\u88c5\u5305\u505a\u5408\u9002\u7684\u8fc7\u6ee4\u548c\u8d1f\u8f7d\u5747\u8861\u3002 <\/code><\/pre>\n
        \u4e8c vxlan<\/h1>\n