PAgP EtherChannel: Desirable/Auto Negotiation

Bundle lab · $29.99

Build a Layer-2 PAgP EtherChannel between two ioll2-xe switches (SW1 and SW2) using a desirable/auto pairing on two parallel links. Bundle Ethernet0/0 and Ethernet0/1 into Port-channel 3, make the port-channel a VLAN 30 access interface on both switches, and verify with show etherchannel summary, show pagp neighbor, show pagp counters, and end-to-end host pings in VLAN 30.

Learning objectives

• Configure a Layer-2 EtherChannel using PAgP with desirable/auto negotiation
• Create and verify a Port-channel interface as an access port in a user VLAN
• Validate PAgP neighbors, bundle status, and counters
• Confirm host-to-host reachability across an aggregated link

Troubleshooting focus

• Mode compatibility: PAgP requires desirable/desirable or desirable/auto; mixing with LACP (active/passive) or static on breaks bundling.
• Member consistency: All member interfaces must share identical Layer-2 parameters (switchport mode, access VLAN, speed/duplex).
• Logical vs physical settings: Apply the final switching mode/VLAN on the Port-channel interface; ensure members inherit and remain consistent.
• Operational state: Check err-disable, STP blocking, or suspended states if bundling fails.
• Verification depth: Use show etherchannel summary, show pagp neighbor, and show pagp counters to isolate negotiation vs consistency faults.