This whitepaper describes the mechanism for using multiple VLANs with Polycom® SoundPoint IP telephones as well as several cases for why they might be used.
By segregating IP phones into their own VLAN(s), security filters can be implemented in the network to block all unnecessary traffic to or from those devices. This helps prevent disruption due to DoS attacks or attempts to compromise the devices. It also allows locking down access to configuration
and signaling servers to only allow access from phones.