• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 439
  • Last Modified:

Speed Mismatch Cisco 2950 and Pix515

My Cisco 2950 switch is connected to a Pix 515E. The problem is that there is a speed mismatch between the two devices. My switch is set to auto and reports half-duplex and the Pix reports full duplex. If I force the the switch to full duplex the link goes down and we lose Internet connectivity. Any ideas why this would be happening.

1 Solution
Make sure the PIX is also set for auto

  interface ethernet1 auto

Or try forcing them both:
  interface ethernet1 100
Then set the switch to 100/full
If you lose connectivity, hard reboot the PIX
The the switch is set to auto and you change it to half duplex, it will become 10/half while the PIX is at 100 full. That's why the link goes down.

So either set them both to auto, or set them manually. But make sure they are set to the same SPEED, not just the same duplex. Mismatched duplex will cause lots of collisions on the half duplex side but only mismatched speed will cause the link to drop.


Featured Post

Prep for the ITIL® Foundation Certification Exam

December’s Course of the Month is now available! Enroll to learn ITIL® Foundation best practices for delivering IT services effectively and efficiently.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now