Cisco 79xx Phone Stuck with 3.1(x) Load, Will Not Connect to CallManager [Cisco Unified IP Phones 7900 Series]

Document ID: 5278

Introduction
Prerequisites
      Requirements
      Components Used
      Conventions
Problem
Solutions
Related Information

Introduction

In order to understand this problem, it is important to understand what a phone load is.

Cisco IP Phones run their own operating system which is stored locally in Flash. This copy of the operating system loaded into the phone’s Flash is known as a phone load. Cisco IP phone loads are typically geared to work with a particular version of Cisco CallManager. Cisco CallManager has a built in method to automatically upgrade the version of the phone load on phones whenever the phone registers to the CallManager server. Unfortunately, there is no automatic downgrade function.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

This document is not restricted to specific software and hardware versions.

Conventions

For more information on document conventions, refer to the Cisco Technical Tips Conventions.

Problem

A Cisco 79xx phone is stuck with 3.1(x) load and will not connect to Cisco CallManager 3.0(x).

Here are two ways the phone can get into this state:

The Cisco CallManager server has been downgraded, and the phones registering to that server still have the load from the later version of Cisco CallManager.
A Cisco 79xx phone running 3.0(x) firmware is connected to a network running both 3.0(x) and 3.1(x). Cisco CallManager servers with the DHCP boot server point the phones to the 3.1 TFTP server, and auto registration is enabled.

The phone starts up and broadcasts for a DHCP server. The DHCP server responds and gives the IP phone the TFTP address of the 3.1 server. The phone is automatically upgraded with the latest 3.1 load for its model, as would be expected in an upgrade situation. Configurations on the phone, however, direct it to try and register itself to the 3.0 Cisco CallManager. This is where the problem shows up.

Solutions

There are several workarounds for this problem.

If possible, downgrade to 3.0-based phone loads before downgrading the Cisco CallManager server to 3.0(x).

Note: Make sure that the 3.0 load exists in the 3.1 TFTP path.
If Cisco CallManager has already been downgraded, edit the SEPXXXXXXXXXXXX.cnf.xml file replacing the Xs with the phone’s MAC address (UPPER CASE) and place on the TFTP path. Repeat this for each phone.
Reset the phone and it should downgrade the load to the version you specified.

Note: If multiple Cisco CallManager servers are on the network and if DHCP for your segment points the phone to a 3.1(x) TFTP server, you will need to manually configure the phone’s TFTP address to point to your 3.0(x) TFTP server.

Related Information

Updated: Feb 02, 2006

Document ID: 5278

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Cisco Unified IP Phones 7900 Series