Layer 3 Etherchannels - Cisco Catalyst 2000 Configuration Handbook

74 Cisco LAN Switching Configuration Handbook
Distribution_Switch_A (config-if)# end
Distribution_Switch_A # copy running-config startup-config

5-3: Layer 3 EtherChannels

An EtherChannel is the aggregation of multiple physical channels into a single logi-
■
cal connection.
■ The single logical connection is referred to as a port channel.
You can configure the port channel to operate as a Layer 3 interface on some switches.
■
When assigned with an IP address, the port channel becomes the logical Layer 3
■
interface.
If any single link of the channel fails, the port channel interface is still accessible
■
through the other links.
■ Layer 3 EtherChannel operation is the same as Layer 2 EtherChannels for traffic dis-
tribution and channel establishment.
Configuration
An EtherChannel offers the capability to bond multiple physical connections for greater
throughput for links that carry traffic for multiple hosts. Because EtherChannel operates
at an almost physical layer, multiple Layer 3 interfaces can be bonded into a single chan-
nel. After the channel has been formed, a virtual interface known as a port channel inter-
face acts as the Layer 3 conduit for all the members of the channel. To configure a Layer
3 EtherChannel, use the following steps:
Create a logical port channel:
1.
(global) interface port-channel number
In global configuration mode, use this command to create the logical port channel
interface. This acts as the Layer 3 interface for all the members of the channel. The
PCs in 192.168.10.0 Subnet
with 192.168.10.1 as Gateway
Access_Switch_A
Figure 5-1 Network Topology for Layer 3 Interface
Configuration
G 1/1
192.168.10.1
Si
Distribution_Switch_A