Cisco GRE （隧道协议）

CHENYI-R1 (config)#do sh int tunnel 1　　
Tunnel1 is up, line protocol is up
　　
Hardware is Tunnel
　　
Internet address is 1.1.1.1/24
　　
MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,
　　
reliability 255/255, txload 1/255, rxload 1/255
　　
Encapsulation TUNNEL, loopback not set
　　
Keepalive not set
　　
Tunnel source 202.1.1.1, destination 61.1.1.1
　　
Tunnel protocol/transport GRE/IP
　　
Key disabled, sequencing disabled
　　
Checksumming of packets disabled
　　
Tunnel TTL 255
　　
Fast tunneling enabled
　　
Tunnel transmit bandwidth 8000 (kbps)
　　
Tunnel receive bandwidth 8000 (kbps)
　　
Last input never, output never, output hang never
　　
Last clearing of "show interface" counters never
　　
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
　　
Queueing strategy: fifo
　　
Output queue: 0/0 (size/max)
　　
5 minute input rate 0 bits/sec, 0 packets/sec
　　
5 minute output rate 0 bits/sec, 0 packets/sec
　　
0 packets input, 0 bytes, 0 no buffer
　　
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
　　
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
　　
0 packets output, 0 bytes, 0 underruns
　　
0 output errors, 0 collisions, 0 interface resets
　　
0 output buffer failures, 0 output buffers swapped out