6. EtherChannel

6. EtherChannel

1. EtherChannel Operation

   • LAN switch-to-switch technique of grouping several Fast Ethernet or Gigabit Ethernet ports into one logical channel
   • When an EtherChannel is configured, the resulting virtual interface is called a port channel
   • EtherChannel vs STP
     • EtherChannel is a link aggregation technology that allows redundant links between devices that will not be blocked by STP
   • Provides
     • fault-tolerance
     • load sharing
     • increase bandwidth
     • redundancy between switches, routers and servers

2. Francisco Vaca Silva

3. Configure EtherChannel

   • EtherChannel support
     • All Ethernet interfaces on all modules must support EtherChannel with no requirement that interfaces be physically contiguous, or on the same module
   • Speed and duplex
     • Configure all interfaces in an EtherChannel to operate at the same speed and in the same duplex mode
   • VLAN match
     • All interfaces in the EtherChannel bundle must be assigned to the same VLAN or be configured as a trunk
   • Range of VLANs
     • An EtherChannel supports the same allowed range of VLANs on all the interfaces in a trunking EtherChannel
   • Configuring EtherChannel with LACP
     • 1. Specify the interfaces that compose the EtherChannel group
     • 2. Create the port channel interface
     • 3. Change Layer 2 settings on the port channel interface

4. Verify and troubleshoot EtherChannel

   • common commands
     • show interfaces port-channel
     • show etherchannel summary
     • show etherchannel port-channel
     • show interfaces etherchannel
   • common issues
     • Ports with different native VLANs cannot form an EtherChannel.
     • Trunking was configured on some of the ports that make up the EtherChannel, but not all of them.
     • If the allowed range of VLANs is not the same
     • The dynamic negotiation options for PAgP and LACP are not compatibly configured on both ends of the EtherChannel