IP Phone deployments, the power of DHCP and auto config

In my 3rd company blog article, I talked about DHCP and auto configuration via DHCP. There are fifteen different feature groups (IP Deskphones Fundamentals, NN43001-368, Appendix B: Provisioning the IP Phones) and 100+ different settings configurable via DHCP (I didn’t count them, I’m estimating). Some of the gotchas I’ve learned over the years are as follows:

• As noted in the 3rd blog post, Stickiness can cause deployment issues for refurb phones– Always add a factory reset to your troubleshooting efforts (**RENEW[MAC]##), which was introduced in UNIStim 3.0, otherwise your refurb phone may not operate as expected when first deployed.
• When you have multiple Signaling Servers– Always make sure that both Sig Servers are using the same IP Phone firmware, otherwise your phones may “upgrade” to an earlier firmware release when they failover, resulting on extended and unexpected downtime.
• Know your current UNIStim firmware. There have been issues in the past where newer IP Phone hardware requires a minimum firmware level, which means that all IP Phones in the environment must be upgraded in order to deploy new phones.
• Learn how to use PRT TNB commands in LD 20 and STAT IP commands in LD 117 (I’m actually planning on doing a future blog post on this topic, since the LD 117 commands can be used to also inventory your IP phones)–
  • Make sure that the TNB is programmed, otherwise you’ll get SRPT062/SRPT0062 – Request to register TN rejected. Reason = UNEQUIPPED.
  • Make sure the set isn’t deployed elsewhere, otherwise you’ll get SRPT062/SRPT0062 – Request to register TN rejected. Reason = DUPLICATE.
  • Make sure the set is the right TYPE, otherwise you’ll get SRPT062/SRPT0062 – Request to register TN rejected. Reason = WRONGTYPE.
  • Make sure the set is of the right TN_TYPE (covered in part 2 of the company series), otherwise you’ll get SRPT062/SRPT0062 – Request to register TN rejected. Reason = CANNOTCONVERT
    • 2004P1, 2004P2, 2210, 2211, 2007, 1140, 2050PC, 2050MC, 6140
    • 2002P1, 2002P2, 1120, 1220, 6120
    • 2001P2, 2033, 1110, 1210
    • 1230
    • 1150
• Know how to troubleshoot your data network– Always make sure that your provisioning method is supported in the subnet where the IP phone is being deployed and know how to check the data network configuration, otherwise your phone might get stuck at “Starting DHCP…” or “Connecting to S1…” (or “Connecting to S2…”)
  • I can’t tell you how many times I’ve seen a telecom tech install an IP Phone into a brand new subnet which has no DHCP configuration options, or a new data switch without correct VLAN settings, and then request help– only to be landed with a bill for not setting up the new subnet correctly.

Another thing that I find extremely helpful is learning the provisioning cycle and the status messages which display on the IP Phone during boot up:

This way, if you get stuck at a particular phase, you know where and can use that to determine your next troubleshooting step. For example;

• If you get stuck at “Starting DHCP…” then you should check (a) is your DHCP server still running, (b) are you in a subnet that provides the DHCP options you need, (c) can your IP phone reach the DHCP server, (d) does the IP Phone firmware support the features you’re trying to push to it?
• If you get stuck at “Attempting TFTP…”, (a) is your TFTP server still running, (b) can you IP Phone reach your TFTP server, (c) are your PRV files correctly configured?
• If you get stuck at “Connecting to S1″ (or S2), (a) is your IP Phone in the right VLAN, (b) Can the IP Phone reach the signaling server, (c) is the signaling server still running?
• If you get stuck at “Connect Svc Forwarding…” then there is something wrong with your signaling server– it’s responded to the initial connect request, and it’s forwarded the request to the signaling server but the signaling server isn’t responding correctly to complete the registration process.