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Network Services
Network services are included because they are critical to the overall functionality of IP telephony environments. The major services are Domain Name Service (DNS), Dynamic Host Configuration Protocol (DHCP) and Network Time Protocol (NTP). This section looks at the configuration and resiliency of these services for high availability, overall manageability, and functionality requirements in the IP telephony environment.
DNS
DNS is an important network service. Table B-22 provides a list of questions that you should ask customers to evaluate configuration and resiliency of DNS in terms of network devices.
| No. | Question | Answer |
|---|---|---|
| 1 | Does the organization have a resilient DNS architecture with primary and secondary DNS servers? |  Yes No |
| 2 | Provide the DNS server IP addresses and your fully qualified domain name. | DNS 1__________________ DNS 2__________________ FQDN__________________ |
Notes/Comments
DNS is not mandatory for deployment of IPT. However, it provides load balancing and redundancy for accessing IPT XML services.
DHCP
DHCP is an important network service for large-scale IP telephone provisioning. All IP telephony implementations should implement DHCP for phone provisioning otherwise, manual phone configuration is required. The DHCP service should support option 150 (to support Cisco IPT implementations), which is one of the custom options that can be configured in the DHCP servers. These custom options allow the DHCP servers to provide additional information to the DHCP clients and, in case of IPT networks, the IP phones and the gateways. Option 150 in Cisco IPT networks provides the TFTP server information to the IPT endpoints. Use the questions in Table B-23 to get information about customer DHCP implementation.
| No. | Question | Answer |
|---|---|---|
| 1 | Does the organization use DHCP services to provide the IP addressing for clients? | Yes No |
| 2 | What DHCP software (including version number) is in use? | MS DHCP Lucent QIP Other Specify |
| 3 | Will the DHCP server support the configuration of customized options? (IP phones accept the TFTP server information in DHCP option 150 or 66.) | Yes No |
| 4 | If the answer to question 3 is yes, can the IPT network use your existing DHCP server to provide the IP addresses to IPT endpoints such as IP Phones and voice gateways? | Yes No |
| 5 | Is the DHCP service resilient with configuration backups and disk mirroring? | Yes No |
| 6 | Do you use a centralized DHCP server for the entire organization? | Yes No |
| 7 | If you have distributed DHCP services at the remote branches, does the router provide the DHCP services, or do you have a separate DHCP server for each branch office? | Provide details in the "Notes/Comments" section. |
Notes/Comments
Add any additional information about the customer's DHCP implementation.
Network Time Protocol
The use of NTP services in the network ensures that all the devices in the network use the same time source to synchronize their clocks. Use Table B-24 to evaluate the existing NTP configuration and setup in the customer's network.
| No. | Question | Answer |
|---|---|---|
| 1 | Does the organization currently use NTP? | Yes No |
| 2 | If the answer to question 1 is yes, what are the NTP IP addresses of the NTP sources? | Source 1_________________ Source 2_________________ |
| 3 | Do you want to configure the IPT devices to synchronize their clocks with NTP servers? | Yes No |
Notes/Comments
Understand how NTP is implemented today in the network and use the information gathered in Table B-24 to implement NTP in the voice devices, such as CallManager servers, IPT application servers, and gateways.
Directories
Organizations use directories to store employee-related information such as e-mail ID, phone numbers, location, user ID, authentication information, etc. Table B-25 provides the list of questions that you should ask the customer to understand the currently deployed directory.
| No. | Question | Answer |
|---|---|---|
| 1 | What directory service is currently deployed in the organization? | Microsoft AD Netscape Sun One iPlanet Version_______________ |
| 2 | Is there a requirement to integrate the IPT applications with your existing corporate directory? | Yes No |
| 3 | If directory integration is not a requirement, are you looking at providing the corporate directory access lookup from IP Phones? | Yes No |
Notes/Comments
Cisco IPT applications such as Cisco CallManager use an embedded directory (DC Directory) to store user information such as password, PIN number, phone number, speed dials, and so forth. If the customer's organization has deployed a directory, Cisco IPT applications can integrate with it, without the embedded directory. This reduces the administrative overhead and provides a single repository for all the applications. Careful planning is required for the successful integration of IPT applications with the existing corporate directory.
Messaging System
Use Table B-26 to gather the information about customer's current existing messaging system.
| No. | Question | Answer |
|---|---|---|
| 1 | What is the current e-mail messaging environment used in the organization? | MS Exchange Lotus Domino Other Version_______________ |
| 2 | Does the organization intend to deploy unified messaging along with the IP telephony deployment? | Yes No |
Notes/Comments
If the customer decides to use unified messaging, you should obtain some preliminary information on its messaging architecture. You can collect detailed information using the Voice-Mail Design Questionnaire in Appendix G.
