| When the IT staff plan for upgrades, especially a VoIP | | | | systems. |
| deployment, a lot of attention is focused on servers, | | | | 2. DNS stands for Domain Name Service. This service |
| applications, switches, routers, and network security. | | | | is what translates easy to remember names on the |
| Almost no attention is paid to the core network | | | | network, like a URL in a browser, to the IP addresses |
| services that allow users to access all these | | | | that the applications running on computers require. |
| wonderful systems, and are in fact essential for VoIP | | | | Without DNS, any network-based applications cannot |
| to even work at all! | | | | be used. DNS is usually provided centrally by |
| If users are unable to access the applications that they | | | | redundant windows servers, and externally by multiple |
| need over the network, or if customers are unable to | | | | small linux boxes running BIND. Unfortunately, |
| access the Internet-based Web services or | | | | sometimes the Windows DNS service has stability |
| applications that they need, all business transactions | | | | issues, and it is tedious and error prone to update the |
| come to an immediate screeching halt. Since | | | | BIND applications on the Linux boxes. |
| application access is so important, it is worthwhile to | | | | 3. NTP stands for Network Time Protocol. There are |
| look at how to make sure everything in the system | | | | many applications that require proper time on the |
| works reliably. | | | | servers and workstations, especially SIP-based voice |
| There are four core network services that have to be | | | | applications and network security applications. NTP is in |
| up and running for users to be able to access their | | | | many cases served from redundant windows servers. |
| applications. These are: | | | | 4. IPAM stands for IP Address Management. It is |
| 1. DHCP stands for Dynamic Host Configuration | | | | important to have an overall IP address management |
| Protocol. This service is what hands the user an IP | | | | method in order to ensure that DHCP and DNS are |
| address on the internal network when they connect. | | | | working properly. Entire new subnets are added in a |
| No network communication can take place without | | | | VoIP deployment, so this is especially important then. |
| having an IP address, as well as the other information | | | | As you can see, high availability core network services |
| that the DHCP service provides, which is a default | | | | are essential to the proper operation of everything on |
| route and the IP addresses of the DNS servers. What | | | | the network, and especially VoIP. In your next upgrade |
| most people don't know, is that usually the DHCP | | | | planning cycle, it is worthwhile to look at improving the |
| service is provided by a non-redundant Windows | | | | availability of the core network services of DHCP, |
| server, or by a router that provides little visibility into the | | | | DNS, NTP, and IPAM. |
| operation of the service. DHCP is essential for VoIP | | | | |