Network Addresses and Subnets

[romiti]

I’m planning a network with network addresses of 10.20.30.x & 10.20.31.x and the subnet mask of 255.255.0.0. I believe that if you have IP address, say 10.20.30.111, you can PING address, say 10.20.31.222. The network is 10.20.x.x, so I should be able to PING any host from any station, does that sound right? I’ve been told that I will need a router (or gateway) between the 10.20.30.x & the 10.20.31.x address?? I believe since they are all the same network this should not be the case. I agree if the subnet mask was 255.255.255.0 this would be the case, but not here. I may also need to add other segments- e.g. 10.20.32.x, etc. in the future.

I will have some switches on the network. If I set up separate VLAN’s, will the switch route between the different VLAN’s? Maybe more informtion is needed, but this will be using Cisco 4500 series switches.

This is all in the design and planning phase, so recommendations welcome!

[DWAM_2 · Accepted solution]

Hello,

if you have network 10.20.x.x and subnet 255.255.0.0 (/16) : all hosts in this subnet can ping each others (exemple : 10.20.30.111 can ping 10.20.31.222).

Yours hosts are located in the same subnet and so in the same vlan.

10.20.x.x <-> 10.20.y.y : OK

You don't need router to communicate.

If you have 10.20.30.x with 255.255.255.0(/24) in one vlan and 10.20.31.x with 255.255.255.0(/24) in another vlan.

10.20.30.x(/24) <-> 10.20.30.y(/24) : OK

10.20.31.x(/24) <-> 10.20.31.y(/24) : OK

10.20.30.x(/24) <-> 10.20.31.x(/24) : OK if you have a router/KO if you don't have a router.

To communicate between vlan you need a router.

4500 with layer 3 do that.

A switch is used to level 2 of Osi.

A router is used to level 3 of Osi.

I think you will find lot of documentations on Internet.

Regards.