Information Technology Reference
In-Depth Information
hand, a switch-to-switch link that has been allowed to negotiate its behavior could end up operating at
10 Mb half-duplex. A nonfunctional link is usually easier to discover than a link that is operational but
not operating at the expected speed or mode.
One of the most common causes of performance issues on 10/100-Mb Ethernet links is one port on the
link operating at half-duplex mode while the other port is operating at full-duplex mode. This
occasionally happens when one or both ports on a link are reset and the autonegotiation process doesn't
result in the same configuration for both link partners. It also happens when users reconfigure one side
of a link and forget to reconfigure the other side. Many performance-related support calls will be avoided
by creating a policy that requires ports for all nontransient devices to be configured for their required
behavior and enforcing the policy with adequate change control measures.
Troubleshooting Ethernet Autonegotiation Between Network Infrastructure
Devices
Figure 23-2 show the process you should follow in troubleshooting Ethernet autonegotiation between
network infrastructure devices.
