Aggregating switch links

Об Etherchannel

EtherChannel is a term used to describe bundling or aggregating 2-8 parallel links. EtherChannel provides a level of link redundancy. If one link in the bundle fails, traffic sent through that link is automatically moved to an adjacent link in the bundle. Normally multiple links between switches creates the potential for bridging loops, but because an EtherChannel bundle is treated as a single logical link by both switches, it avoids the problem. Spanning Tree sees the bundle as a single link so individual ports will not be placed in a blocked STP state, allowing greater bandwidth utilization. If there are two redundant EtherChannel bundles, one entire EtherChannel will be blocked by STP to prevent a loop. Any changes made to an interface after the EtherChannel has been created will be automatically make the same change to all other ports in that bundle. Also – bundles cannot form if any of the assigned ports are SPAN ports. EtherChannel links can be either access or trunk links, but if they are trunked (usually the case), they require the following the be the same on all connected interfaces:

• VLANs
• Trunking Mode
• Native VLAN
• Speed
• Duplex