IBM L2/3 Common Spanning Tree configuration Ieee 802.1D and Pvst, Verify the Lacp trunk status

Configure the Cisco Core1 and Core2 for tagged LACP trunks

In the configuration mode, access the interface level for G0/11 and G0/12:

conf t

interface range G0/11-12

Enable IEEE 802.1Q tagging with VLAN 5 untagged and allow only the VLANs which should be carried over the LACP trunk:

switchport trunk encapsulation dot1q switchport trunk native vlan 5 switchport trunk allowed vlan 5,10,20,99 switchport mode trunk

Disable the Cisco proprietary dynamic trunk protocol DTP:

switchport nonegotiate

Enable LACP by choosing a channel-group number and use active mode:

channel-group 2 mode active

That creates virtual interface called Port-channel2 (or short Po2).

For the port range G0/1-2, there should be already a static trunk configured (see 7.6.1, “Layer 2 configuration with 802.1Q tagging and trunk failover” on page 70). If not, the above steps must be repeated with G0/11-12 replaced by G0/1-2. Consequently only the aggregation mode must be changed for ports G0/1 and G0/2 (could be done for the virtual interface Po1 instead):

interface range G0/1-2 channel-group 1 mode active end

Remember that the ports are still shut down.

Verify the LACP trunk status

Before enabling the configured ports to get the LACP trunk up, Spanning Tree must be activated. After that and re-enabling the ports, the status of the LACP trunks can be checked with:

￿/i/l2/lacp/dump on the GbESM

￿show lacp int and show lacp nei on the Cisco switch

Important: Do not enable the configured ports at this time to avoid a Layer 2 loop, what could be deadly for the whole network. Spanning Tree has to be configured and activated before. See 7.7.2, “Common Spanning Tree configuration - IEEE 802.1D and PVST” on page 84 and 7.7.3, “Rapid Spanning Tree IEEE 802.1w” on page 95.

7.7.2 Common Spanning Tree configuration - IEEE 802.1D and PVST

The GbESM interoperates with Cisco Per VLAN Spanning Tree (PVST) protocol using up to 16 Spanning Tree groups. This section shows how to configure separate Spanning Tree Groups (STG) for each VLAN using Cisco’s proprietary PVST and IEEE 802.1D (Common/Mono Spanning Tree).

84Nortel Networks L2/3 Ethernet Switch Module for IBM Eserver BladeCenter