IP Phone Network Architecture

The CIC network architecture is built around the concept of VLANs. A VLAN (Virtual-LAN) is a network within a network which you access by tagging network traffic for that VLAN. Any network can have many VLANs and can allow for routing traffic between the VLANs as needed. VLANs serve as a way to isolate certain devices from the general network (typically called the data VLAN). They also serve to isolate the traffic from those devices from general view, whether by devices not on that specific VLAN or by malicious parties attempting to penetrate the network.

It is important to isolate all the voice traffic in a CIC system onto a separate VLAN, typically called the voice VLAN. This means that all devices that generate/pass on voice traffic need to exist on the voice VLAN. The devices includes the CIC Servers, phones, Media Servers, Gateways, and Interaction SIP Proxies.

Accessing CIC Servers, Media Servers, and Proxies from the data VLAN allows for easy remote access. Giving servers access to both VLANs complicates configuration, though, as they must have multiple NICs (Network Interface Controllers) and proper DNS/DHCP configuration on both VLANs. The configuration can become more complicated when including remote sites.

The following diagrams show the ideal configuration for the network over multiple offices, but your actual configuration can differ. For instance, although the Managed Proxy and Media Server for a remote office are shown as two distinct servers, in some cases it is appropriate to have them share the same physical device.

The following diagram shows a wide view of a typical network configuration for managed IP phones.

Each site, including the home office, needs access to the voice VLAN over the WAN, and each site needs its own DHCP and DNS servers. An exception is very small offices that can use the DNS and DHCP servers of the home office over the WAN. However, it increases WAN traffic so, if possible, you should avoid. Also, any sites that have Interaction SIP Station I and II deployed must have a DHCP server on both the voice VLAN and the data VLAN.

The following diagrams show basic home office and remote office network architecture.

DNS and DHCP servers are separate, non-CIC Servers in the CIC system network. It allows for DHCP and DNS maintenance without putting the CIC server at risk. Use a static IP address for each of the non-phone devices (CIC server, Media Server, Proxy, Gateway) so that the system can contact them in the event of a reboot without the querying device needing to refresh its data.

For phones, use dynamic IP addresses that the DHCP server assigns to them for maintenance and configuration considerations.