Interface Configuration
7750 SR OS Interface Configuration Guide Page 417
LAG Commands
lag
Syntax [no] lag [lag-id]
Context config
Description This command creates the context for configuring Link Aggregation Group (LAG) attributes.
A LAG can be used to group up to 16 ports into one logical link. The aggregation of multiple physical 
links allows for load sharing and offers seamless redundancy. If one of the links fails, traffic will be 
redistributed over the remaining links. Up to 16 links can be supported in a single LAG, up to 200 
LAGs can be configured on a node. 
NOTE: All ports in a LAG group must have autonegotiation set to Limited or Disabled.
There are three possible settings for autonegotiation:
• “on” or enabled with full port capabilities advertised
• “off” or disabled where there is no autonegotiation advertisements
• “limited” where a single speed/duplex is advertised. 
When autonegotiation is enabled on a port, the link attempts to automatically negotiate the link speed 
and duplex parameters. If autonegotiation is enabled, the configured duplex and speed parameters are 
ignored. 
When autonegotiation is disabled on a port, the port does not attempt to autonegotiate and will only 
operate at the speed and duplex settings configured for the port. Note that disabling autonegotiation 
on gigabit ports is not allowed as the IEEE 802.3 specification for gigabit Ethernet requires 
autonegotiation be enabled for far end fault indication.
If the autonegotiate limited keyword option is specified the port will autonegotate but will only 
advertise a specific speed and duplex. The speed and duplex advertised are the speed and duplex 
settings configured for the port. One use for limited mode is for multispeed gigabit ports to force 
gigabit operation while keeping autonegotiation is enabled for compliance with IEEE 801.3.
7750 SR OS requires that autonegotiation be disabled or limited for ports in a Link Aggregation 
Group to guarantee a specific port speed.
The no form of this command deletes the LAG from the configuration. Deleting a LAG can only be 
performed while the LAG is administratively shut down. Any dependencies such as IP-Interfaces 
configurations must be removed from the configuration before issuing the no lag command.
Default No LAGs are defined.
Parameters lag-id — The LAG identifier, expressed as a decimal integer.
Values 1 — 200 (7750 SR-1and 7750 SR-c12/4: 1 — 64)