Reference Guide

422 | Interfaces
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Port channel benefits
Port channels are transparent to network configurations and can be modified and managed as one interface.
For example, you configure one IP address for the group and that IP address is used for all routed traffic on
the port channel.
With this feature, the user can create larger-capacity interfaces by utilizing a group of lower-speed links.
For example, the user can build a 5-Gigabit interface by aggregating five 10-Gigabit Ethernet interfaces
together. If one of the five interfaces fails, traffic is redistributed across the four remaining interfaces.
Port channel implementation
FTOS supports two types of port channels:
• Static—Port channels that are statically configured
• Dynamic—Port channels that are dynamically configured using Link Aggregation Control Protocol
(LACP). For details, see Link Aggregation Control Protocol (LACP)
The S5000 supports 128 port-channels and 8 members per LAG.
As soon as a port channel is configured, FTOS treats it like a physical interface. For example, IEEE
802.1Q tagging is maintained while the physical interface is in the port channel.
Member ports of a LAG are added and programmed into hardware in a predictable order based on the port
ID, instead of in the order in which the ports come up.
A physical interface can belong to only one port channel at a time.
Each port channel must contain interfaces of the same interface type/speed.
Port channels can contain a mix of 1G/10G Ethernet interfaces, and the interface speed used by the port
channel is determined by the first port channel member that is physically up. FTOS disables the interfaces
that do match the interface speed set by the first channel member. That first interface may be the first
interface that is physically brought up or was physically operating when interfaces were added to the port
channel. For example, if the first operational interface in the port channel is a Gigabit Ethernet interface,
all interfaces at 1-Gigabit are kept up, and all 10-Gigabit interfaces that are not set to 1-Gigabit speed or
auto-negotiate are disabled.
FTOS brings up 1G/10G interfaces that are set to auto negotiate so that their speed is identical to the speed
of the first channel member in the port channel.
1G/10G interfaces in port channels
When both 1G/10G interfaces and GigE interfaces are added to a port channel, the interfaces must share a
common speed. When interfaces have a configured speed different from the port channel speed, the
software disables those interfaces.