IP Telephony Design Question

[MarkMonteleone]

I am helping to design a IP telephony setup that will end up encompassing 3000 thousand phones. In the campus designs that I have done in the past, if the ammount of phones/Pc's exceeded the switches capacity, I'd stack a couple and feed a Core switch, 4500 or 6500 remotely on Gig fiber.

Question here is(with gig fiber links to buildings), how many phones is too many when we are talking about stacking switches to cover a particular branch or campus? I know that the

3750-48PS says it can handle 32G-bps but at a 700 phone site that would be 15 switches not including redundancy. I know that I could probably trunk the ports but would be worried about quality. So would I install a more robust switch rather than stacking 15 3750's? What about redundacy?

[bigbhai]

hi,

the quality of voice will not be a worry if you are trying any qos in it and by stacking 15 switches i dont think there should be any issues regarding redudency.

[MarkMonteleone]

Thanks for your response. What about trunking the ports and using some existing 3524's? In reference to having maximun uptime percentages, what about the redundacy factor, does that mean 30 switches?

[ovanegas]

Mark:

keep in mind that there is a limit of nine(9) Cat3750 per stack.

see:

http://www.cisco.com/en/US/customer/about/ac123/ac114/ac173/ac224/cisco_packet_enterprise_solution0900aecd800b19a1.html

there is a limit of nine(9) Cat3750 per stack.

Also check your phone power requirements. if using class 3, you might need to use c3750-24ps instead of the 48ps. good luck,