> # E PortChannels

> An E PortChannel refers to the aggregation of multiple E ports into one logical interface to provide higher aggregated bandwidth, load balancing, and link redundancy. PortChannels can connect to interfaces across switching modules, so a failure of a switching module cannot bring down the PortChannel link.

> A PortChannel has the following features and restrictions:

> - Provides a point-to-point connection over ISL (E ports) or EISL (TE ports). Multiple links can be combined into a PortChannel.
> - Increases the aggregate bandwidth on an ISL by distributing traffic among all functional links in the channel.
> - Load balances across multiple links and maintains optimum bandwidth utilization. Load balancing is based on the source ID, destination ID, and exchange ID (OX ID).
> - Provides high availability on an ISL. If one link fails, traffic previously carried on this link is switched to the remaining links. If a link goes down in a PortChannel, the upper protocol is not aware of it. To the upper protocol, the link is still there, although the bandwidth is diminished. The routing tables are not affected by link failure. PortChannels may contain up to 16 physical links and may span multiple modules for added high availability.

> Note See the Cisco MDS 9000 Family NX-OS Fabric Configuration Guide for information about failover scenarios for PortChannels and FSPF links.

> Copyright 2010-2013, Cisco Systems, Inc. All rights reserved.