EtherChannel & Link Aggregation

Build a two-link LACP EtherChannel between SW1 and SW2 using an active/passive pairing. The logical Port-channel2 carries VLAN 20 as an access link so two hosts on opposite switches can communicate. Verify with show etherchannel summary, show lacp neighbor, and host-to-host pings.

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.

Build a two-link LACP EtherChannel between SW1 and SW2 and convert the Port-channel into an 802.1Q trunk that explicitly carries VLANs 40 and 41. Validate end-to-end host reachability across VLAN 40 and confirm the trunk’s allowed VLAN list and switchport mode on the logical port-channel. Emphasis: deterministic EtherChannel configuration on member interfaces, correct trunking on the Port-channel, and verification with IOS show commands.

Build a Layer-3 EtherChannel between two IOS XE routers using LACP active/active. Two parallel router links are bundled into Port-channel5, which carries a /30 transit. R2 hosts a loopback; R1 installs a static route to reach it. Validate that the Port-channel holds the IP (members do not), that the bundle is up and uses both links, and that pings across the /30 and to the loopback succeed. Emphasis: deterministic EtherChannel configuration and Layer-3 port-channel practices.

Build a two-link LACP EtherChannel between two layer-2 switches as an access port for VLAN 60, then tune the global load-balancing algorithm to src-dst-ip so traffic distributes more evenly. Verify Po6 status, the hashing method, and end-to-end host reachability.

Build an LACP Layer-2 EtherChannel between SW1 and SW2 so Rapid-PVST+ treats two parallel links as one logical Port-channel 7. Without EtherChannel, STP will block one of the two access links. With LACP active on both members and Port-channel 7 as an access port in VLAN 70, STP shows a single forwarding interface (Po7) and both physical links forward as one logical channel. Two hosts in VLAN 70 verify end-to-end connectivity.

Build a routed LACP EtherChannel (Port-channel 8) between two iol-xe routers and route real inter-LAN traffic using static routes. Two parallel physical links (Ethernet0/0 and Ethernet0/1) on each router are bundled into a single Layer-3 Port-channel with a /30 transit. Each router serves a local /24 LAN with an alpine host. Validate that Po8 is up/up, static routes are present, and end-to-end host pings succeed across the aggregated uplink.

Advanced CCNP troubleshooting lab: a pair of Layer-2 switches are connected by a two-link EtherChannel intended to carry VLAN 90 between access hosts. The starter configuration ships broken on purpose: the inter-switch bundle won’t form due to incompatible aggregation modes, and a trunk allow-list drift on one side prunes VLAN 90. Diagnose with IOS show commands, correct the EtherChannel mode so LACP forms the Port-channel, and restore trunk policy so same-VLAN hosts can communicate.

Advanced EtherChannel capstone, run as a fault hunt. The uplink bundle between two access switches is not passing traffic and the hosts either side cannot reach each other. Some members are up, the bundle is not, and nothing was recorded. You get symptoms and the required end state — no fault list. Both ends of a bundle have to agree about several things at once, and only one end was touched during the change — so comparing them is the exercise.