02-05-2009 04:53 AM - last edited on 03-25-2019 04:04 PM by ciscomoderator
I'm looking for a Best Practice guide that describes how many hosts are recommended per VLAN..
Maybe there are differences in "normal" hosts and "broadcast-intensive" hosts...
Regards,
Remco
02-05-2009 05:18 AM
"In various Cisco design documents, recommendations as to VLAN size vary: "it depends". Still, one rough set of numbers is 500 hosts in a broadcast domain, if speakers are using TCP/IP and fairly quiet"
02-05-2009 06:28 AM
Remco,
The common design is to use /24 for LANs and /30 for point-to-point WAN/LAN links.
With that said, the subnet allocation is often driven by business requirement. For instance, if you create a server Vlan and the business requires to only have 13 servers on that Vlan, you aren't going to waste a /24 on it, do you?
Same can be said if the business has 300 servers and want all servers in the same Vlan, you need something bigger than a /24.
HTH,
__
Edison.
02-05-2009 06:44 AM
Hmm. I Know that.. If you are using a private address space, it doesn't matter to use a /24 for 13 servers...
Was just wondering if there were "hard" numbers of hosts by best practice.
If you have a group of 600 student computers, are you going to create one, big /22 subnet ? I think it is better to create 3 / 24 networks, or one /23 and one /24. Broadcast domains stay small in this way...
02-05-2009 06:50 AM
Hi Remco,
I don't think that there hard numbers recommendation but it all depend on your design. You could create a /22 as you pointed out and avoid the need of routing various VLANs if they are all share the same functions.
02-05-2009 09:25 AM
As a point of reference, 1000 hosts will completely saturate a 10Mb network with nothing but control traffic.
Stick with /24 and route where necessary.
If you go above /24 implement private-vlans to control your broadcasts.
I have done work on a campus network that is a /20 and it sucks ... avoid if at all possible.
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