Link to home
Start Free TrialLog in
Avatar of publicvoid
publicvoidFlag for United States of America

asked on

Reducing a /16 network to a /24

I have a live network that is in the 10.10.0.0/16 range.  I am creating VLANS and subnets and moving most of the nodes out of the range all together.  I was wondering though, is there a way to create a vlan/subnet in the 10.10.1.0/24 range and keep communications up until I can change the grandfathered network to the /24 range?  Right now I'm going to have to take the network down, change the masks change the grandfathered range to a 24 and then create the VLAN that I need.

Anyway to do this with a live network?  Working with a Cisco 6509...
ASKER CERTIFIED SOLUTION
Avatar of SIM50
SIM50
Flag of United States of America image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Avatar of publicvoid

ASKER

Thought so but I though maybe there was some ninja solution I didn't know about.
Avatar of bbao
> a way to create a vlan/subnet in the 10.10.1.0/24 range and keep communications up

there is NO problem for hosts with /16 mask to communicate with others with /24 mask, IF:

1. they are in the same phsicsl network, VLAN or broadcast domain

AND

2. the /16 mask hosts are actually in the range of 10.10.1.0/24.

e.g. 10.10.1.100/16 can talk with. 10.10.1.200/24, but 10.10.2.100 cannot talk to 10.10.1.100/24 (technically the latter can receive the former's packets but will reply to other subsets if a default gateway is available).

does it make sense?

therefore if you carefully plan the IPs, new hosts can communicate with SOME hosts on the grandfathered network, though not all of them.