Cisco CCNA mock exam questions sample test – Question 387

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You apply the following commands to a router named R2:
R2(config)# interface Tunnel1
R2(config-if)# ip address 172.16.1.2 255.255.255.0
R2(config-if)# ip mtu 1400
R2(config-if)# ip tcp adjust-mss 1360
R2(config-if)# tunnel source 2.2.2.2
R2(config-if)# tunnel destination 1.1.1.1
Which statement is NOT true with regard to this configuration?

A. The physical IP address of R2 is 2.2.2.2
B. The connection will operate in IP mode
C. The configuration will increase packet fragmentation
D. The configuration alters the maximum segment size


Correct Answer: C

Explanation:
The configuration will not increase packet fragmentation. Conversely, it will reduce it by lowering the maximum transmission unit to 1400 and the maximum segment size to 1360
bytes.
Most transport MTUs are 1500 bytes. Simply reducing the MTU will account for the extra overhead added by GRE. Setting the MTU to a value of 1400 is a common practice, and it will
ensure unnecessary packet fragmentation is kept to a minimum.
The other statements are true. The physical address of R2 is 2.2.2.2, while the tunnel interface address is 172.16.1.2.
Because you have not issued any command that changes the connection, it will operate in the default mode of IP.
The configuration does alter the maximum segment size with the ip tcp adjust-mss 1360 command.
Objective:
WAN Technologies
Sub-Objective:
Configure, verify, and troubleshoot GRE tunnel connectivity
References:
Home > Network Infrastructure > WAN, Routing and Switching > How to configure a GRE tunnel