When the IT staff plan for upgrades, especially a VoIP deployment, a lot of attention is focused on servers, applications, switches, routers, and network security. Almost no attention is paid to the core network services that allow users to access all these wonderful systems, and are in fact essential for VoIP to even work at all!

If users are unable to access the applications that they need over the network, or if customers are unable to access the Internet-based Web services or applications that they need, all business transactions come to an immediate screeching halt. Since application access is so important, it is worthwhile to look at how to make sure everything in the system works reliably.

There are four core network services that have to be up and running for users to be able to access their applications. These are:

1. DHCP stands for Dynamic Host Configuration Protocol. This service is what hands the user an IP address on the internal network when they connect. No network communication can take place without having an IP address, as well as the other information that the DHCP service provides, which is a default route and the IP addresses of the DNS servers. What most people don’t know, is that usually the DHCP service is provided by a non-redundant Windows server, or by a router that provides little visibility into the operation of the service. DHCP is essential for VoIP systems.

2. DNS stands for Domain Name Service. This service is what translates easy to remember names on the network, like a URL in a browser, to the IP addresses that the applications running on computers require. Without DNS, any network-based applications cannot be used. DNS is usually provided centrally by redundant windows servers, and externally by multiple small linux boxes running BIND. Unfortunately, sometimes the Windows DNS service has stability issues, and it is tedious and error prone to update the BIND applications on the Linux boxes.

3. NTP stands for Network Time Protocol. There are many applications that require proper time on the servers and workstations, especially SIP-based voice applications and network security applications. NTP is in many cases served from redundant windows servers.

4. IPAM stands for IP Address Management. It is important to have an overall IP address management method in order to ensure that DHCP and DNS are working properly. Entire new subnets are added in a VoIP deployment, so this is especially important then.

As you can see, high availability core network services are essential to the proper operation of everything on the network, and especially VoIP. In your next upgrade planning cycle, it is worthwhile to look at improving the availability of the core network services of DHCP, DNS, NTP, and IPAM.

Find out more about VoIP and Networking.

Great articles from voice, security, and network engineers that are in the field doing designs and deployments on a daily basis.