Chapter 8 Troubleshooting and Maintenance

Cisco Unified IP Phone Resets Unexpectedly

Identifying Intermittent Network Outages

Intermittent network outages affect data and voice traffic differently. Your network might have been experiencing intermittent outages without detection. If so, data traffic can resend lost packets and verify that packets are received and transmitted. However, voice traffic cannot recapture lost packets. Rather than retransmitting a lost network connection, the phone resets and attempts to reconnect its network connection.

If you are experiencing problems with the voice network, you should investigate whether an existing problem is simply being exposed.

Verifying DHCP Settings

The following suggestions can help you determine if the phone has been properly configured to use DHCP:

1.Verify that you have properly configured the phone to use DHCP. See the “Network Configuration Menu” section on page 4-4for more information.

2.Verify that the DHCP server has been set up properly.

3.Verify the DHCP lease duration. Cisco recommends that you set it to 8 days.

Cisco Unified IP Phones send messages with request type 151 to renew their DHCP address leases. If the DHCP server expects messages with request type 150, the lease will be denied, forcing the phone to restart and request a new IP address from the DHCP server.

Checking Static IP Address Settings

If the phone has been assigned a static IP address, verify that you have entered the correct settings. See the “Network Configuration Menu” section on page 4-4for more information.

Verifying Voice VLAN Configuration

If the Cisco Unified IP Phone appears to reset during heavy network usage (for example, following extensive web surfing on a computer connected to same switch as phone), it is likely that you do not have a voice VLAN configured.

Isolating the phones on a separate auxiliary VLAN increases the quality of the voice traffic. See the “Understanding How the Cisco Unified IP Phone Interacts with the VLAN” section on page 2-3for details.

Cisco Unified IP Phone 7960G/7940G Administration Guide for Cisco Unified Communications Manager 7.0 (SCCP)

 

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Cisco Systems 7940G Identifying Intermittent Network Outages, Verifying Dhcp Settings, Checking Static IP Address Settings
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7960G, 7940G specifications

Cisco Systems has long been a leader in creating innovative networking and communication solutions. Among their range of Voice over IP (VoIP) phones, the Cisco 7960G and 7940G stand out as robust, versatile devices that cater to the needs of modern businesses. Released in the early 2000s, these models respectively combine functionality, ease of use, and key features tailored for effective communication.

The Cisco 7960G is a high-end model designed for users who demand advanced features and functionalities. It comes with a large backlit LCD display that not only enhances visibility but also provides easy navigation through various options. The phone supports up to six lines, allowing users to manage multiple calls effortlessly. Its user-friendly interface includes programmable feature buttons and a 10/100 Ethernet switch, enabling seamless integration into existing networks.

On the other hand, the Cisco 7940G is a more basic model designed for users who require essential features for their business communications. It includes a monochrome LCD screen and supports a maximum of two lines. Despite its simplicity, the 7940G is equipped with several key features such as integrated speakerphone and mute options, making it ideal for day-to-day communication needs. Both models support Power over Ethernet (PoE), eliminating the need for separate power adapters and ensuring a cleaner, more organized workspace.

In terms of technologies, both the 7960G and 7940G leverage the Session Initiation Protocol (SIP) for signaling and media exchange. They also support secure communication through protocols like Secure Real-time Transport Protocol (SRTP) and Transport Layer Security (TLS). This ensures that businesses can engage in confidential conversations without the risk of interception.

The characteristics that make these models appealing include durability, ease of configuration, and reliability. Organizations can benefit from Cisco’s reliable support and regular updates, ensuring that their communication infrastructure remains robust and secure. With features designed for scalability, both phones can easily integrate into larger systems while maintaining high call quality.

In summary, Cisco’s 7960G and 7940G VoIP phones are exemplary devices that cater to a variety of business communication scenarios. With their blend of functionality, support for essential technologies, and reliable performance, they continue to serve organizations effectively in an increasingly interconnected world. Whether used in a bustling office or as part of a dynamic telecommunications strategy, these models offer excellent value and performance.
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