good voice subnet ?

razamrazam Member Posts: 39 ■■□□□□□□□□
Hello all,

i have a small question regarding voice implementation.

about to start a voice project, have around 2000 phones.. what is recommended voice subnet ?

1 single subunet of /16 ? which will cover ip address for all the phones ?


have 8 subnets of /24 ? each subnet for around 250 phones ?

which one is a good practice ?

thank you


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    azaghulazaghul Member Posts: 569 ■■■■□□□□□□
    A /16 subnet....eek!

    In our environment (multi-site, government) we usually marry up the voice subnet size with the data subnet, as there are typically a similar number of devices in each. So if you have a data subnet of /24, do the same for voice...worst I've found in our network is /23.
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    aaron0011aaron0011 Member Posts: 330
    /24 and I typically use class b range for voice VLAN with third octet matching data subnet.
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    shodownshodown Member Posts: 2,271
    Create a large class b subet. Break each closet into its own smaller. Keep them small as too much voice traffic in a subnet can get chatty.
    Currently Reading

    CUCM SRND 9x/10, UCCX SRND 10x, QOS SRND, SIP Trunking Guide, anything contact center related
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    swildswild Member Posts: 828
    With 3500 phones on our primary cluster, we have a /16 network broken up by site with most sites being a /25 or /26 with a few /24 or /27 and 2 sites being a /23. We try to minimize the number of "wasted" ip addresses while keeping in mind possible future growth. If this is for a single large campus, I would try to segment by building or floor or functional group, depending on the size of each, with the ideal max of a /24 subnet.

    Our voice and our data are worked by two different groups so there really isn't any correlation between the 2. Most sites have much more data than phones once you consider public use computers, employees without phones (contracted programmers mostly), printers, badge access, ip cameras, digital signage, servers, routers, switches, and probably more that I am not thinking of right now.
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    JollycorkJollycork Member Posts: 149
    Don't forget that many businesses will want Intergrated systems between voice, email, video, IM, and even a CRM system.
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    razamrazam Member Posts: 39 ■■□□□□□□□□
    thank you all for your valuable suggestions.

    going with /24 voice subnets. will need around 10 subnets for /24 to cover 2500 phones
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