Concept Guide

Port Channel Benets
A port channel interface provides many benets, including easy management, link redundancy, and sharing.
Port channels are transparent to network congurations and can be modied and managed as one interface. For example, you congure
one IP address for the group and that IP address is used for all routed trac on the port channel.
With this feature, you can create larger-capacity interfaces by utilizing a group of lower-speed links. For example, you can build a 40-Gigabit
interface by aggregating four 10-Gigabit Ethernet interfaces together. If one of the ve interfaces fails, trac is redistributed across the
three remaining interfaces.
Port Channel Implementation
The Dell Networking OS supports static and dynamic port channels.
• Static — Port channels that are statically congured.
• Dynamic — Port channels that are dynamically congured using the link aggregation control protocol (LACP). For details, refer to Link
Aggregation Control Protocol (LACP).
There are 128 port-channels with 16 members per channel.
As soon as you congure a port channel, the system 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 the hardware in a predictable order based on the port ID, instead of in the order in
which the ports come up. With this implementation, load balancing yields predictable results across line card resets and chassis reloads.
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 100, 1000, or 10000 Mbps Ethernet interfaces and TenGigabit Ethernet interfaces. The interface speed
(100, 1000, or 10000 Mbps) the port channel uses is determined by the rst port channel member that is physically up. The system disables
the interfaces that do match the interface speed that the rst channel member sets. That rst interface may be the rst interface that is
physically brought up or was physically operating when interfaces were added to the port channel. For example, if the rst operational
interface in the port channel is a Gigabit Ethernet interface, all interfaces at 1000 Mbps are kept up, and all 100/1000/10000 interfaces that
are not set to 1000 speed or auto negotiate are disabled.
100/1000/10000 Mbps Interfaces in Port Channels
When both 100/1000/10000 interfaces and TenGigabitEthernet interfaces are added to a port channel, the interfaces must share a
common speed. When interfaces have a congured speed dierent from the port channel speed, the software disables those interfaces.
The common speed is determined when the port channel is rst enabled. At that time, the software checks the rst interface listed in the
port channel conguration. If you enabled that interface, its speed conguration becomes the common speed of the port channel. If the
other interfaces congured in that port channel are congured with a dierent speed, the system disables them.
For example, if four interfaces (TenGig 0/0, 0/1, 0/2, and 0/3) in which TenGig 0/0 and TenGig 0/3 are set to speed 100 Mb/s and the
others are set to 10000 Mb/s, with all interfaces enabled, and you add them to a port channel by entering channel-member
tengigabitethernet 0/0-3
while in port channel interface mode, and the system determines if the rst interface specied (TenGig
0/0) is up. After it is up, the common speed of the port channel is 100 Mb/s. The system disables those interfaces congured with speed
1000 Mb/s or whose speed is 1000 Mb/s as a result of auto-negotiation.
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Interfaces