ISCW Hotspot: EIGRP over GRE Tunnels

Topology:



Q1. What is the reason for the ping failure between the CiscoSims-HQ router and the 192.168.1 193 interface on the Branch2 router?

A. The default route is missing from the Branch2 router.
B. When running EIGRP over GRE tunnels, you must manually configure the neighbor address using the eigrp neighbor ipaddress command.
C. The tunnel numbers for the tunnel between the HQ router and the Branch2 router do not match.
D. The tunnel source is incorrect on the Branch2 router. It should be serial 2/0.
E. The AS number for the EIGRP process on Branch2 should be 1 and not 11.


Explanations:-

Branch2#sh run
HQ#sh run



- The default route of Branch2 is normal and points at the outbound GRE-channel can be used to deliver dynamic routing information and no special configuration is necessary for routing protocols. The exhibit shows that the tunnel source of Branch2 is serial2/0. So as to enable route delivery, the AS number of EIGRP must be the same in the whole EIGRP area. So we choose E.

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Q2. For the following statements, what is preventing a successful ping between the CiscoSims-HQ router and the 192.168.1.10 interface on the Branch3 router?

A. The default route is missing from the Branch3 router.
B. The tunnel interface numbers for the tunnel between the HQ router and the Branch3 router do not match.
C. The tunnel source is incorrect on the Branch3 router. It should be serial 2/0.
D. The IP address on the tunnel interface for the Branch3 router has wrong IP mask. It should be 255.255.255.252
E. The network statement under router EIGRP on the Branch3 router is incorrect. It should be network 192.168.2.0 0.0.0.255


Explanations:-



- The default route of Branch3 is missing , which can not transmit data correctly, so A is right.
- Tunnel numbers only have local significance and routers at both ends do not need to match, so B is wrong.
- The tunnel source on the Branch3 router is serial2/0, so C is wrong.
- The IP address on the tunnel interface has no function and only needs to be on the same network segment, so D is wrong.
- The network statement under router EIGRP is right. It should be network 192.168.1.0/24, so E is wrong.

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Q3. What is preventing the CiscoSims-HQ router and the Branch1 router from building up an EIGRP neighbor relationship?

A. When running EIGRP over GRE tunnels, you must manually configure the neighbor address using the eigrp neighbor ipaddress command.
B. The tunnel destination address is incorrect on the HQ router. It should be 10.2.1.1 to match the interface address of the Branch1 router.
C. The tunnel source is incorrect on the Branch1 router. It should be serial 2/0.
D. The default route is missing from the Branch1 router.
E. The tunnel interface numbers for the tunnel between the HQ router and Branch1 router do not match.


Explanations:-



- The dynamic routing protocol running over GRE tunnels does not need a particular configuration, so A is wrong.
- The tunnel destination address of center router should point to the interface address of Branch1 router, so B is right.
- The tunnel source on the Branch1 router is right, so C is wrong.
- The default route on the Branch1 router is operational, so D is wrong.
- The interface numbers of tunnel between the CiscoSims-HQ router and Branch1 router do not need to match , which only have the local significance, so E is wrong.

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Q4. What is the reason that tunnel 5 on the CiscoSims-HQ router is down when its companion tunnel on the Branch5 router is up?

A. The IP address on the tunnel interface on Branch5 is incorrect. It should be 192.168.1.16
255.255.255.252
B. The tunnel source for tunnel 5 is incorrect on the HQ router. It should be serial 2/0.
C. The tunnel numbers for tunnel between the HQ router and the Branch5 router do not match.
D. The tunnel destination address for tunnel 5 is incorrect on the HQ router. It should be 10.2.5.1 to match the interface address of the Branch5 router.
E. The tunnel interface for tunnel 5 on the HQ router is in the administrative down state.


Explanations:-

HQ# sh run


- The IP address on the tunnel interface has no function and only needs to be on the same network segment, so A is wrong.
- The tunnel source for tunnel 5 on the CiscoSims-HQ router is serial 1/0. It should be interface serial 2/0 connected to the other side, so B is right.
- The interface numbers of tunnel between the CiscoSims-HQ router and Branch 1 router do not need to match , which only have the local significance, so C is wrong.
- The tunnel destination address for tunnel 5 on CiscoSims-HQ is 10.2.5.1 matching with the peer, so D is wrong.
- The tunnel interface for tunnel 5 on the CiscoSims-HQ router has not the shutdown command, thus, the interface can be enabled normally, so E is wrong.

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Q5. What is preventing the 192 168.1.150 network from appearing in the CiscoSims-HQ router's routing table?

A. The default route is missing from the Branch4 router.
B. The IP address on the E0/0 interface for the Branch4 router has the wrong IP mask. It should be 255.255.255.252
C. The network statement under router EIGRP on the Branch4 router is incorrect. It should be network 192.168.1.0 0.0.0.255
D. When running EIGRP over GRE tunnels, you must manually configure the neighbor address using the eigrp neighbor ipaddress command.
E. The IP address on the tunnel interface on Branch4 is incorrect. It should be 192.168.1.12 255.255.255.252


Explanations:-



- The default route of the Branch4 router is operational, so A is wrong.
- The e0/0 interface on the Branch4 router is the internal network interface. The subnet mask is correct, so B is wrong.
- EIGRP should advertise the entire network 192.168.1.0 instead of a single IP address, so C is right.
- The dynamic routing protocol running over GRE tunnels does not need a particular configuration, so D is wrong.
- Generally, the IP addresses on the tunnel interface have no real significance, which only need to be able to communicate with each other on the same network segment, so E is wrong.

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