EIGRP configuration

hi guys

recently, i have an assignment to do, and it is abt the routing protocol configuration on a router. as the requirement, i need to assign each of the router with a loopback address to represent a campus' network, because there are 10 campuses need to be created. Also, 15 networks of 130hosts for each of the campus.

hence, my solution is to subnet the given class B network "134.115.0.0".

what i do first is that i borrow 4 bits to create 14 usable network to meet the campus network requirement.

2ndly, since we need to provide 15 networks for each of the campuses, i further divided on each of the campus subnet network address. therefore, i borrow another 4 bits upon the subnet network.

finally, i try to configure the router based on the addressing scheme above. however, i got stuck on the process and i would like any one of you could have idea for me........

before i configure the router, i picked up a subnetwork for a campus which is "134.115.16.0 /20 ", also, i assigned the address 134.115.16.1 as the loopback1 address to represent the network.
based on the requirement of the campus, there must be 15 netwoks under the "134.115.16.0 /20". therefore, i tried to subnet the 134.115.16.0 network into a /30 mask network for all the serial connections. however, i got a problem on configuring the serial interface with the problem " network 134.115.16.4 (hostaddress 134.115.16.5) overlapped with the loopback 1 address which is the /20 mask address. :evil: Yet, as we all know, the EIGRP routing protocol support VLSM and CIDR. the two interface are actually assigned with address in different mask, but why the router could not differentiate from each other instead of dropping error message like that!!!!!!

I know i wrote somthing on the top, but if u r reading up till here, i really really thanks for your time and hope you could give me an idea!!! thanks you so much!!!

if you've already assigned an interface (including the loopback) of the router as 134.115.16.1/20, then you can't also use 134.115.16.5/30, because that address is technically part of the /20 you assigned to the loopback - i.e. you're trying to assign IP addresses that share part of the same space to two different interfaces.

If you were going to break the networks down to /30's, you'd need to assign the loopback with something like 134.115.16.1/30 instead of using the entire /20 mask, then you would be able to use 134.115.16.5/30 for a different interface.

Thnx tiamat for ur idea, , i will try on it!!!

Hi ccnx,
Yes EIGRP routing protocol support VLSM and CIDR, subnet mask is include in the EIGRP update packet.
But it doesn’t mean that you can use ip address that share the part of same space to two different interfaces.
No two interface of router should share part of the same space i.e. every interface should be part of different network.

In your design you are trying to use IP addresses that share part of the same space to two different interfaces.
For your network requirement you can follow what tiamat said.

I hop this will clear your dougt why your router dropping error message like that!!!!!! so don't blame to router......

not to be rude but can someone say duh?

Well you succeeded in being rude. People come here to ask questions if we said DUH after every post then the community would die out.