Core issue
EtherChannel aggregates the bandwidth of up to eight compatibly-configured ports into a single logical link. All Ethernet ports on all modules, including those on a standby supervisor engine, support EtherChannel with no requirement that ports be contiguous or on the same module. All ports in each EtherChannel must be the same speed. Fast EtherChannel and Gigabit EtherChannel port bundles allow you to group multiple Fast or Gigabit Ethernet ports into a single logical transmission path between the switch and a router, host, or another switch.
Port Aggregation Control Protocol (PAgP) and Link Aggregation Control Protocol (LACP) are two protocols that allow ports with similar characteristics to form a channel through dynamic negotiation with adjoining switches. PAgP is a Cisco-proprietary protocol that can be run only on Cisco switches and those switches released by licensed vendors. LACP, which is defined in IEEE 802.3ad, allows Cisco switches to manage Ethernet channeling with devices that conform to the 802.3ad specification.
Note: Make sure to read the workstation or server Network Interface Card (NIC) documentation for any guidelines that apply to interoperation with Cisco switches.
Resolution
Perform these general configuration tasks on the Cisco Catalyst switch Ethernet ports:
- Issue the set vlan command to assign a VLAN to the Ethernet ports.
- Issue the set trunk mod/port off command to disable trunking on the Ethernet ports (highly recommended).
- Issue the set spantree portfast mod/port enable command to enable spanning tree portfast on the Ethernet ports (highly recommended).
- Issue the set port channel command to set EtherChannel modes on the Ethernet ports.
- Issue the set port channel all distribution command to configure an EtherChannel load-balance distribution algorithm.
For more configuration details, refer to Configuring EtherChannel Between a Catalyst Switch Running CatOS and a Workstation or Server.
