Lacp Parameters - Cisco WS-C2948G-GE-TX Configuration Manual

Chapter 6 Configuring Fast EtherChannel and Gigabit EtherChannel
Table 6-2
Mode
passive
(Default)
active

LACP Parameters

LACP uses the following parameters:
•
•
•
When enabled, LACP always tries to configure the maximum number of compatible ports in a channel,
up to the maximum that is allowed by the hardware (eight ports). If LACP is not able to aggregate all the
ports that are compatible (for example, the remote system might have more restrictive hardware
limitations), then the system places all the ports that cannot be actively included in the channel in hot
standby state and uses them only if one of the channeled ports fails.
You can configure different channels with ports that have been assigned the same administrative key. For
example, if you assign eight ports to the same administrative key, you may configure four ports in a
channel using LACP active mode and the remaining four ports in a manually configured channel using
the on mode. An administrative key is meaningful only in the context of the switch that allocates it; there
is no global significance to administrative key values.
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
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EtherChannel Modes That Use LACP (continued)
Description
LACP mode that places a port into a passive negotiating state in which the port responds
to LACP packets that it receives but does not initiate LACP packet negotiation.
LACP mode that places a port into an active negotiating state, in which the port initiates
negotiations with other ports by sending LACP packets.
System priority
Each switch running LACP must have a system priority. You can specify the system priority
automatically or through the CLI (see the
The switch uses the MAC address and the system priority to form the system ID. This system ID is
used during negotiation with other systems.
Port priority
Each port in the switch must have a port priority. You can specify the port priority automatically or
through the CLI (see the "Specifying the Port Priority" section on page
the port number form the port identifier. The switch uses the port priority to decide which ports to
put in standby mode when a hardware limitation prevents all compatible ports from aggregating.
Administrative key
Each port in the switch must have an administrative key value. You can specify the administrative
key value automatically or through the CLI (see the
section on page 6-19). The administrative key defines the ability of a port to aggregate with other
ports. The following factors determine a port's ability to aggregate with other ports:
Port physical characteristics, such as data rate, duplex capability, and point-to-point or shared
–
medium
– Configuration constraints that you establish
"Specifying the System Priority" section on page
"Specifying an Administrative Key Value"
Understanding LACP
6-19).
6-19). The port priority and
6-17