Troubleshooting High Availability
A trunk (also called LAG or port channel) can be configured automatically or can be defined manually with or without the LACP protocol.
Due to their resiliency and traffic load balancing, trunks can be used for inter-switch communication within a cluster (auto-LAG) or for general network connectivity (user-configured LAG).
You can verify a trunk (LAG) status with the command trunk-show:
CLI network-admin@switch > trunk-show format switch,name,ports,speed,lacp-mode,status
switch name ports speed lacp-mode status
--------- -------------------- ----- ------- --------- ------
pnswitch1 ports1-4 1-4 10g off up
pnswitch1 ports5-8 5-8 10g off up
pnswitch1 ports9-12 9-12 10g off up
pnswitch1 ports13-16 13-16 10g off up
Trunks can be configured with or without LACP. The following example shows the LACP options available when creating a trunk:
CLI network-admin@switch > trunk-create name port1-4 ports 1,4 lacp-mode
L ACP is off
LACP passive mode
LACP active mode
When LACP is set to active or passive mode it helps detect link and configuration changes, whereas in off mode it is up to the network admin to deal with the trunk bring up process and to avoid configuration mistakes/oversights (such as asymmetries in the configuration).
Clusters and vLAGs provide the underlying redundancy structure for network communications. You can check that a cluster and a vLAG are functioning properly with the following commands. First verify the cluster status (online or offline) with the command cluster-show:
CLI network-admin@switch > cluster-show
name state cluster-node-1 cluster-node-2 tid ports remote-ports
------------- ------ ------------- ------------ --- -------- ------------ pnclusterodd online pnswitch1 pnswitch3 15 4,36,128 4,36,129
pnclustereven online pnswitch2 pnswitch4 0 4,8,128 4,8,129
Then verify the vLAG status(es) with the command vlag-show:
CLI (network-admin@pnswitch1) > vlag-show
name cluster mode switch port peer-switch peer-port statu local-state lacp-mode
----------------------- ------------ ------------- --------- ------------- ----------- ------------- ----- --------- ---------
pnvlag1 pnclusterodd active-active pnswitch1 trunk-to-plus pnswitch3 trunk-to-plus norma enabled,up off
pnvlag2 pnclustereven active-active pnswitch2 49 pnswitch4 18 norma enabled,up active
A vLAG is a logical entity that relies upon its port members (physical ports with an operational Layer 1 status) and upon the underlying cluster.
Therefore, first check that the vLAG status is normal and the state is “enabled,up”. If there are problems with the vLAG, work back through the objects it depends on: the cluster, and ultimately the physical ports and the cables.