Preview Tool

Cisco Bug: CSCub21489 - Duplex Mismatch on PC-Port of IP Phone causes slow speed

Last Modified

Sep 22, 2020

Products (34)

  • Cisco IP Phone 8800 Series
  • Cisco Unified IP Phone 7945G
  • Cisco Unified IP Phone Expansion Module 7914
  • Cisco Unified IP Phone 7971G-GE
  • Cisco Unified Wireless IP Phone 7920
  • Cisco Unified IP Phone 9951
  • Cisco Unified IP Phone 7962G
  • Cisco Unified Wireless IP Phone 7925G
  • Cisco Unified IP Phone 7941G
  • Cisco Unified IP Phone 7961G-GE
View all products in Bug Search Tool Login Required

Known Affected Releases


Description (partial)

Duplex mismatch on the link between the PC and the PC port of the 6945 IP phone resulting in low throughput in direction PC -> IP phone. 
The link establishes to 100Full on PC port of IP phone, whereas it is 100Half on the PC, creating duplex mismatch.

Load is SIP 9-3-1-5.

Cat_4510 - IP phone - PC

Cat_4510 is set with Auto 10/100.
PC is set with Auto 10/100/1000. 

IP phone related settings for failing scenarios:
1) Automatic Port Synchronization - ENABLED, Switch port remote config - AUTO, PC Port remote config - AUTO
2) APS - ENABLED, SW port - DISABLED, PC port - AUTO
3) APS - ENABLED, SW port - AUTO, PC port - DISABLED

Related Community Discussions

<key>CSCub21489</key> - Duplex Mismatch on PC-Port of IP Phone causes slow speed
Hello Is it possible this bug is also present in 7962G model with  SCCP42.9-3-1SR2-1S? I have same kind of behavior with that phone type.
Latest activity: Dec 09, 2013
Bug details contain sensitive information and therefore require a account to be viewed.

Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
  • Number of Related Support Cases
Bug information is viewable for customers and partners who have a service contract. Registered users can view up to 200 bugs per month without a service contract.