API Guide

eth1/1/9 Aggressive 22 Err-disabled
eth1/1/10 Normal 22 Unknown
Supported
Releases
10.4.3.0 or later
Link Aggregation Control Protocol
Group Ethernet interfaces to form a single link layer interface called a LAG or port channel. Aggregating multiple links between
physical interfaces creates a single logical LAG, which balances traffic across the member links within an aggregated Ethernet
bundle and increases the uplink bandwidth. If one member link fails, the LAG continues to carry traffic over the remaining links.
For information about LAG load balancing and hashing, see Load balancing.
You can use LACP to create dynamic LAGs exchanging information between two systems (also called Partner Systems) and
automatically establishing the LAG between the systems. LACP permits the exchange of messages on a link to:
● Agree on the identity of the LAG to which the link belongs.
● Move the link to that LAG.
● Enable the transmission and reception functions.
LACP functions by constantly exchanging custom MAC PDUs across LAN Ethernet links. The protocol only exchanges packets
between ports you configure as LACP-capable.
Modes
A LAG includes three configuration modes—on, active, and passive.
On
Sets the Channeling mode to Static. The interface acts as a member of the static LAG.
Active Sets the interface in the Active Negotiating state. LACP runs on any link that is configured in this mode. A
port in Active mode automatically initiates negotiations with other ports by using LACP packets. A port in
Active mode can set up a port channel with another port in Active mode or Passive mode.
Passive Sets the interface in an Inactive Negotiating state, but LACP runs on the link. A port in Passive mode also
responds to negotiation requests (from ports in Active mode). Ports in Passive mode respond to LACP
packets. A port in Passive mode cannot set up a LAG with another port in Passive mode.
● There is no dual-membership in static and dynamic LAGs:
○ If a physical interface is a part of a static LAG, the channel-group id mode {active | passive} command is
rejected on that interface.
○ If a physical interface is a part of a dynamic LAG, the channel-group id command is rejected on that interface.
● You cannot add static and dynamic members to the same LAG.
● There is a difference between the shutdown and no interface port-channel commands:
○ The shutdown command on LAG xyz disables the LAG and retains the user commands.
○ The no interface port-channel channel-number command deletes the specified LAG, including a dynamically
created LAG. The interfaces restore and are ready for configuration.
● A maximum of 128 port channels with up to 32 members per port channel are allowed.
Configuration
LACP is enabled globally by default. You can configure aggregated ports with compatible active and passive LACP modes to
automatically link them.
1. Configure the system priority in CONFIGURATION mode (1 to 65535; the higher the number, the lower the priority; default
32768).
lacp system-priority priority-value
Layer 2
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