Simple Question

bpage587

New to the forum* I'm in the beginning phases of studying for the CCENT and have what I assume is a relatively simple question on the topic of router implementation in regards to class C subnetting:

In answering a question posed on page 159 (in reference to figure 3.21, pg 160) of the CCENT Study Guide (Todd Lammle) I was able to understand mask values, block sizes, etc. The question at hand asks why hostA cannot communicate with hostB. After exhausting my theories, which didn't take long, I read on to find the answer that perplexes me still.
::RouterA's serial 0/0 is configured with an IP address in the hostA LAN subnet range::

**While I was able to deduce this from the given info, I was amiss as to why RouterA could not be in the same subnet as hostA.**

Anyone?

Thanks

CodeBlox

The Host A is going to likely be on Router A's (fast | gigabit)ethernet interface subnet, not the serial interfaces. That serial interface is typically point to point to another router(Within the scope of CCENT). So they can't be on the same subnet.

EDIT: You could think of it this way, each port on the router should belong do a different subnet (at the ccent level). I say "at the ccent level" because I'm not too sure if that changes. And you aren't going to have a host connected to a routers serial port.