VLSM Table - How do you write single IP address?

lon21

I've been reading Todd Lammle book last night and could not figure out how to write ip a single address in vlsm. I thought I'd sleep on it and re-read in the morning, to see it it helped. tbh I actually had a dream about ip address LOL... anyways and found a table which is useful for designing VLSM networks.

The table is for class C network, when using VLSM would we only use VLSM on class C network? If not I guess the table would not be worth memorising?

Also if I have a Class C 192.168.1.0 network which has 60 host and 6 host. We can see that we can use a 192 mask which gives us 60 host (62 host - 2 extra) which has a increment of 64 (block). 248 mask give us 6 host with a block of 8.

I guess the range would be, is this correct?
60 Host
192.168.1.0 - 192.168.1.63 /26

6 Host
192.168.1.64 - 192.168.1.71 /29


But when using the table how would I express this as a ip single address?


Thanks

miller811

You need to list the subnet and then reverse the mask (wild card mask)

192.168.1.0/26 (0.0.0.63) is the inverse of the real mask 255.255.255.192
192.168.1.64/29 (0.0.0.7) is the inverse of the real mask 255.255.255.248

lon21

Thanks.

So its the 1st ip address followed by the subnet.

I guess I would write the wild card in the cisco router?

Also as the table above is only for a class C network. Would there be any question which asks you to use VSLM other than a class C network?

Thanks

mallyg27

VLSM can be used for any class.

lon21

mallyg27 wrote: »

VLSM can be used for any class.

Is there a general table for vlsm like the one above?

jwashington1981

lon21 wrote: »

Is there a general table for vlsm like the one above?

Lammle has a chart under the section "Classless Inter-Domain Routing (CIDR)". That's something you definitely want to memorize. When looking at the chart, you'll also notice that it follows a pattern which will help you memorize it.