Cisco Catalyst 2960 Series, Configuration Manual

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Switch Stack and PAgP
With PAgP, if the active switch fails or leaves the stack, the standby switch becomes the new active switch.
The new active switch synchronizes the configuration of the stack members to that of the active switch. The
PAgP configuration is not affected after an active switch change unless the EtherChannel has ports residing
on the old active switch.
Switch Stacks and LACP
With LACP, the system ID uses the stack MAC address from the active switch, and if the active switch
changes, the LACP system ID can change. If the LACP system ID changes, the entire EtherChannel will flap,
and there will be an STP reconvergence. Use the
stack-mac persistent timer command to control whether
or not the stack MAC address changes during a active switch failover.
Default EtherChannel Configuration
The default EtherChannel configuration is described in this table.
Table 38: Default EtherChannel Configuration
Default Setting Feature
None assigned. Channel groups
None defined. Port-channel logical interface
No default. PAgP mode
Aggregate-port learning on all ports. PAgP learn method
128 on all ports. PAgP priority
No default. LACP mode
Aggregate-port learning on all ports. LACP learn method
32768 on all ports. LACP port priority
32768. LACP system priority
LACP system priority and the switch or stack MAC
address. LACP system ID
Load distribution on the switch is based on the
source-MAC address of the incoming packet. Load-balancing
Related Topics
Configuring Layer 2 EtherChannels , on page 342
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
337
Information About EtherChannels