Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide ...

LACP trunking 4• When you enable SuperSpan globally, and then create a new VLAN, the new VLAN inherits theglobal SuperSpan state.• In many cases, generic debugging is not useful. If multiple STP instances are configured, it canbe difficult to identify content for a specific instance from the extensive output that may begenerated. Use the debug spanning-tree port and debug spanning-tree vlan commands todefine specific instances for debugging.Common diagnostic scenarios• Spanning Tree loops.• Spanning Tree reacts to topology changes and port flapping.• Port flapping can trigger a new Spanning Tree learning process.LACP trunkingThe Link Aggregation Control Protocol (LACP) allows ports on both sides of a redundant link toautomatically configure themselves into a trunk link (aggregate link), eliminating the need formanual configuration. LACP has two modes:• Active mode – When active link aggregation is enabled, the Brocade port can exchangestandard LACP Data Unit (LACPDU) messages to negotiate trunk group configuration with theport on the other side of the link. In addition, the Brocade port actively sends LACPDUmessages on the link to search for a link aggregation partner at the other end of the link, andcan initiate an LACPDU exchange to negotiate link aggregation parameters with anappropriately configured remote port.• Passive mode – In passive link aggregation, the Brocade port can exchange LACPDU messageswith the port at the remote end of the link, but this port cannot search for a link aggregationport or initiate negotiation of an aggregate link. In passive mode, the port at the remote end ofthe link must initiate the LACPDU exchange.When you enable link aggregation on a group of Brocade ports, the Brocade ports can negotiatewith the ports at the remote ends of the links to establish trunk groups.Trunk show commandsThe following show commands display information about trunking configurations.show lagSyntax: show lagThis command displays trunk information for the ports managed by the CPU. The CPU assigns thehash values evenly to the trunk ports managed by the CPU.Brocade# show lagMax number of trunks: 128Available: 127Configured number of server trunks: 1Configured trunks:Trunk ID: 1Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide 9353-1002426-02