Subnetting Question! Please Help.

Swaswaswa

Hello world.

I purchased my ICND1 100-101 exam not too long ago, I am scheduled for August 17th! That being said, I need help...

Subnetting/VLSM has been making my head spin for the past couple of days...

The scenario is:

Routers A, B, C, and D.

Router A needs 60 hosts on one interface and 75 hosts on another interface.
Router B needs 300 hosts.
Router C needs 40 hosts.
Router D needs 10 hosts.
Plus 3 serial connections, so 6 hosts.

I need to accommodate the largest network which is 300. So my first range should look like -
192.168.1.0/23
N 192.168.1.0
1 192.168.1.1
L 192.168. 254
B 192.168.255

So that means the 192.168.1.0 block is full, and this is where I am stuck. I know the next address block is 192.168.2.0 but if I add the other hosts, they will not be able to communicate, right? Or am I looking at this the wrong way?

alias454

You're adding networks to the routers. Routers route packets between different networks. Perform the VLSM subnetting and trust your numbers.

regards,

Simrid

As above.

To be able to talk between networks you need a layer 3 device, a router happens to be one - So you're in luck.

If it's spanning across multiple routers like in this example, a routing protocol such as OSPF, EIGRP or RIP could be used to advertise those routes. OSPF and RIP are in the scope of the CCENT so if you nail them, things should start to click.

Note: RIPv2 and upwards can support VSLM.

Any questions, drop me a PM.

Swaswaswa

Thanks a lot Alias and Simrid. I don't know why I did not think of the routing protocols. Well it's safe to say I no longer have any problems with VLSM.