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C7960 connecting @ 100meg/half duplex?

Hi all,

I have about 8 phones that negotiate at half duplex even though switchport and phone are configured to auto.

This is 8 phones in about 1000 - if I force them to connect at 100 meg by unlocking the phone and forcing the configuration to 100F it connects at 100 meg full duplex.

Why would I have to manually configure these phones when all others work fine?

Thanks in advance!


Re: C7960 connecting @ 100meg/half duplex?

Autonegotiation issues may result from nonconforming implementation, hardware incapabilities, or software defects. When NICs or vendor switches do not conform exactly to the IEEE specification 802.3u, problems may result. Hardware incompatibility and other issues may also exist as a result of vendor-specific advanced features, such as autopolarity or cabling integrity, which are not described in IEEE 802.3u for 10/100 Mbps autonegotiation. Generally, if both the NIC and the switch adhere to IEEE 802.3u autonegotiation specifications and all additional features are disabled, autonegotiation should properly negotiate speed and duplex, and no operational issues should exist.

New Member

Re: C7960 connecting @ 100meg/half duplex?


I had a similar issue where the switch ports were set on autonegotiate and the switchports of the Ip phone also.Unfortunately,some PC's were configured at 100/full (settings could not be changed for some reason) and although my PC port on the ip phone was also set on 100/full,the real status of the port was 100/half.

For some NIC's this was not an issue but for those who did had a problem we had to force the PC port of the phone to autonegiate.

I asked Cisco and they came up with a very nice document were states that the PC port and the switchport,both of the phone,must be equal configured.

My initial configuration (switchport autoneg and PC port 100/full) is not supported by Cisco.

Hope this is helpfull to you.

Kind regards,

Kurt De Neef

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