voip network subnet problem

[dmao]

I was told that cisco callmanager max arp table was 1024, so the voip subnet should be within 24(255.255.255.0). if I put all uc parts in a big subnet as 16(255.255.0.0) to avoid layer3 routing issue, is it ok in performance in real?

 

[jeter]

How could that statement be true when you can much more phones per server. The actual amount will be determine by the actual MCS. Refer to Cisco Call Managers SRND

Go Army!
Tek-TIP Member 19,650
CCNA, CCNA Voice, CCNP, CCVP
Avaya IP Office 500, CS1000

 

[dmao]

thanks for your help!

 

[dmao]

I found some articles about my question in cisco SRND. it is said that UC network will become problem if subnet is beyond 1024 devices.
=======================================================

The recommendation to limit the number of devices in a single Unified Communications VLAN to
approximately 512 is not solely due to the need to control the amount of VLAN broadcast traffic. For
Linux-based Unified CM server platforms, the ARP cache has a hard limit of 1024 devices. Installing
Unified CM in a VLAN with a IP subnet containing more than 1024 devices can cause the Unified CM
server ARP cache to fill up quickly, which can seriously affect communications between the Unified CM
server and other Unified Communications endpoints. Even though the ARP cache size on
Windows-based Unified CM server platforms expands dynamically, Cisco strongly recommends a limit
of 512 devices in any VLAN regardless of the operating system used by the Unified CM server platform