Recommended number of hosts per subnet

joch2joch · ‎10-03-2005

Hi all,

I came across some text in the CCNA material long ago that says the recommended size of an IP network/segment should not exceed 500 hosts.

Does anyone know if this recommendation is still valid?

Thanks!

J

andrew.butterworth · ‎10-03-2005

On a project I did a couple of years ago the TAC engineer that was involved specifically said to use nothing higher than a /23 subnet for IP-only VLAN'ss and no more than a /24 for multiprotcol VLAN's (IPX). I never actually found any documentation detailing these recommendations but have used them ever since as the TAC guy was very (very) good.....

It also depends on the topology of your network. Cisco recommend a single VLAN/Subnet per access switch (2 VLAN's where voice is deployed) so it is highly likely on a 24-port switch you would have two /27 VLAN's/Subnets. Obviously this concept is blown away a bit with the stacking technology of the 3750's though....

HTH

Andy

Georg Pauwen · ‎10-03-2005

Hello,

I guess it depends on the traffic patterns, and the amount of traffic. The old rule used to be 80-20, meaning that 80% of the traffic would stay local within the subnet, and 20% would go to the destinations. That rule now has been reversed...

500 hosts seems a lot and is probably an upper limit. If possible, I would not make a subnet bigger than a class C network, that is, 254 hosts. But you would have to look at your network over time and check with the users, to verify if they experience slow response times.

HTH,

GP

joch2joch · ‎10-06-2005

Hi folks, thanks for the info!

Joe