Hello
When doing IP planning for your data vlans (pc access vlan), do you account for address that will be taken by Cisco phones (DHCP request) in the data vlan before they are switched to the correct voice vlan by CDP ?
I heard some people disable spanning-tree portfast configuration to give time for CDP to switch the phone in the voice vlan and avoid exhausting the DATA vlan ip address. This seems like a half assed solution.
In the event of a complete campus shutdown/restart, Cisco phones will create dhcp exhaustion of your data vlan if this is not taken into consideration.
Accounting for cisco-phone make the number of available address for PCs quite limited.
Is this me or this kind of topic is overlooked/not talked about to CCNA/CCNP R&S students, yet necessary for correct enterprise operation ?
The networks I've been operating/learning on do not take this into consideration. When campus would reboot (very rare occasion) The address taken by the phone int the data vlan had to be cleared manually in the DHCP server to give some space to the PCs. By that time, the DHCP request process would have ended and the PC would have obtained an Apipa address since none were available from the DHCP, pc would end need to be restarted or ipconfig /release /renew, once the the required addresses would be freed.
I was wondering how you handle this in the networks you manage ? Is there something I'm missing ?
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