Please help

schneeman

I want to ask a question.We have got two router

R1(DTE)

---

(DCE)R2
| |
| |
---- ----
And R2 Serail interface ip address is 192.1.1.5/30 and R2 ethernet ip adress is 192.1.1.65/26 question is that Which series of command can be used for a LAN to LAN connection between R1 and R2 on R1?
a) interface ethernet 0
ip address 192.1.1.129 255.255.255.192
no shutdown
b) interface ethernet 0
ip address 192.1.1.97 255.255.255.192
c) interface serial 0
ip address 192.1.1.4 255.255.255.252
clock rate 56000
d) interface serial 0
ip address 192.1.1.6 255.255.255.252
no shutdown
e) router rip
network 192.1.1.0
network 192.1.1.128
f) router rip
version 2
network 192.1.1.0
Answer is : A D F

I am very sure about D and F because we must use version 2 rip because of VLSM and D also right because its inte same subnet of R2 serial interface in 255.255.255.252 A is okey correct. But why B is incorrect it's also in 255.255.255.192 network (64-12 if choice A (128-192) is correct then B must be correct because ip address is 192.1.1.97 97 is between 64 and 128 same as choice A (192.1.1.129 is between 128 and 192).
Why Choice B is incorrect WHY WHY please give me answer.
Thx for everything.

wildfire

You are right A is indeed correct as its in the 3rd subnet for a .192 mask (26) all I can think fir is that the no shutdown command is missing from that answer that seems to be in the other answers. Therefore the port would still be in shutdown.

Which series of commands can be used for a LAN to LAN connection

schneeman

i forgot this line in here.
Original question
b) interface ethernet 0
ip address 192.1.1.97 255.255.255.192
no shutdown

So what ? Why B is incorrect in here.
Why why why ?.answer is : A D F
Why B is incorrrrrreeeeeccccttt ?.

forbesl

schneeman wrote:

i forgot this line in here.
Original question
b) interface ethernet 0
ip address 192.1.1.97 255.255.255.192
no shutdown

So what ? Why B is incorrect in here.
Why why why ?.answer is : A D F
Why B is incorrrrrreeeeeccccttt ?.

B in incorrect because that IP address falls within the subnet range assigned to the ethernet segment on R2.

If you notice, R2's ethernet address is 192.1.1.65/26. That means the available host range for that subnet is 192.1.1.66 through 192.1.1.126 (127 is broadcast). You cannot assign 192.1.1.97 to e0 on R1 because that host is part of the subnet assigned to R2's LAN.

rossonieri#1

good one...

schneeman

That's correct.
Thank you my friend.
I understand it now.

wildfire

And R2 Serail interface ip address is 192.1.1.5/30 and R2 ethernet ip adress is 192.1.1.65/26 question is that Which series of command can be used for a LAN to LAN connection between R1 and R2 on R1?

The lan to lan connection means that the two ether net ports connected together would have to be on the same subnet! so b would indeed be correct for a lan to lan connection would it not?

forbesl

The lan to lan connection means that the two ether net ports connected together would have to be on the same subnet! so b would indeed be correct for a lan to lan connection would it not?

Look at the question again. The ethernet interfaces are not connected together. The routers are separated by a serial interface connection. The scenerio is about setting up the routers so that the LANs connected to the ethernet interfaces on the two routers can "talk" to each other over the serial connection.

It is possible for hosts on two completely different interfaces separated by another connection to share the same network/subnet, but you would have to set up bridge irb on both routers. That is beyond the scope of CCNA, and not what this question is about.

wildfire

Ok get you now I had a similar question for BSCI which asked about connecitng lan to lan with routers toghether on two 3620.