Chapter 14 Configuring Portchannels; Portchannel Examples - Cisco DS-C9216I-K9 Configuration Manual

Configuring PortChannels
PortChannels refer to the aggregation of multiple physical interfaces 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. Specifically, a PortChannel has the following functionality:
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Cisco MDS 9000 Family of switches support 128 PortChannels with 16 interfaces per PortChannel.
This chapter discusses the PortChannel feature provided in the switch.
This chapter contains the following topics:
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PortChannel Examples

PortChannels on Cisco MDS 9000 Family switches allow flexibility in configuration. illustrates three
possible PortChannel configurations:
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OL-7753-01
Provides a point-to-point connection over an 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.
PortChannel Examples, page 14-1
About PortChanneling and Trunking, page 14-3
About Load Balancing, page 14-5
Considerations for PortChannel Configurations, page 14-6
Default Settings, page 14-7
PortChannel A aggregates two links on two interfaces on the same switching module at each end of
a connection.
PortChannel B also aggregates two links, but each link is connected to a different switching module.
If the switching module goes down, traffic is not affected.
C H A P T E R
Cisco MDS 9000 Fabric Manager Switch Configuration Guide
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