The following example shows how to configure tunnel entropy
calculation for GRE mode of the tunnel interface:
Device> enable
Device# configure terminal
Device(config)# interface tunnel 21
Device(config-if)# tunnel source 10.1.1.1
Device(config-if)# tunnel destination 172.168.2.1
Device(config-if)# tunnel mode gre ip
Device(config-if)# tunnel key 4683
Device(config-if)# tunnel entropy
Device(config-if)# end
The following is sample output from the
show interfaces tunnel command, which
displays that tunnel entropy calculation is enabled with a 24-bit key:
Device# show interfaces tunnel 21
Tunnel21 is up, line protocol is up
Hardware is Tunnel
MTU 17864 bytes, BW 100 Kbit/sec, DLY 50000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive not set
Tunnel source 10.1.1.1, destination 172.168.2.1
Tunnel protocol/transport GRE/IP
Key 0x124B, sequencing disabled
Checksumming of packets disabled
Tunnel Entropy Calculation Enabled (24-bit Key)
Tunnel TTL 255, Fast tunneling enabled
Tunnel transport MTU 1472 bytes
Tunnel transmit bandwidth 8000 (kbps)
Tunnel receive bandwidth 8000 (kbps)
Last input never, output never, output hang never
Last clearing of "show interface" counters 00:03:07
Input queue: 0/375/0/0 (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 IP multicasts)
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 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out