Execute the displa interface tunnel command on a router to display the information of the GRE tunnel interface as follows:

Execute the displa interface tunnel command on a router to display the information of the GRE tunnel interface as follows:

<Router> displa interface Tunnel O

Tunnelo current state: UP

Line protocol current state: UP

Description: Tunnelo Interface

The Maximum Transmit Unit is 1476

Internet Address is 192.1.2.1/24 Primar

Encapsulation is TUNNEL , agg regation ID not set

Tunnel source 10.1.11.1 , destination 10.1.13.1

Tunnel keepalive enable , Period ( 10 s ) , Retries ( 3 )

Tunnel protocol/transport GRE/IP

GRE ke disabled

Checksumming of GRE packets disabled

Last 300 seconds input: 0 btes/sec , 0 packets/sec

Last 30 0 seconds output: 0 btes/sec , 0 packets/sec

4 packets input , 72 btes

0 input error

1 packets output , 24 btes

0 0utput error

It can be known from the above information.( Choose one or more )
A . The tunnel interface is in the UP state, and the MTU is 1476 bytes
B . The Keeplive function is enabled on the tunnel interface .Once the router does not receive the Keeplive message from the other party within 30s , the tunnel is considered unavailable.Although the tunnel interface is still in the UP state, the tunnel interface is a static route for the outgoing interface Will disappear from the routing table ;
C . tunnel channel does not start verification, verification can not start
D . tunnel channel source lP address 192.1.1.1