Connectrix MDS-Series Cisco: ISL Bounce Does Not Change Time on the iInterface but on the Logical Port Channel

This article explains how to interpret link events on an ISL that is a member of a Port-Channel.

An ISL interface that is part of logical port-channel does not update the "last changed" timestamp after a flap or reset.

ISL port fc3/1 is part of Port-channel 200 with the following "last changed" timestamp.

mds9513(config-if)# show interface fc3/1
fc3/1 is trunking
  Hardware is Fibre Channel, SFP is short wave laser w/o OFC (SN)
    Port WWN is xx:xx:xx:xx:xx:xx:xx:xx
    Peer port WWN is xx:xx:xx:xx:xx:xx:xx:xx
    Admin port mode is auto, trunk mode is on
    snmp link state traps are enabled
    Port mode is TE
    Port vsan is 10
    Speed is 4 Gbps
<Snip>
 Belongs to port-channel 200
    Trunk vsans (admin allowed and active) (10)
    Trunk vsans (up)                       (10)
    Trunk vsans (isolated)                 ()
    Trunk vsans (initializing)             ()
<Snip>
 Interface last changed at Sun Jul 19 20:24:36 2015

The port-channel 200 output:

mds9513(config-if)# sh int po200
port-channel 200 is trunking
    Hardware is Fibre Channel
    Port WWN is xx:xx:xx:xx:xx:xx:xx:xx
    Admin port mode is auto, trunk mode is on
    snmp link state traps are enabled
    Port mode is TE
    Port vsan is 10
<Snip>
Member[1] : fc3/1
    Interface last changed at Sun Jul 19 20:24:36 2015

mds9513(config-if)# show clock
23:02:18.026 JST Mon Jul 20 2015

The ISL interface link was shut down and reset as shown below:

mds9513(config-if)# sh log last 10
2015 Jul 20 23:04:04 mds9513 %PORT-5-IF_TRUNK_DOWN: %$VSAN 10%$ Interface port-channel 200, vsan 10 is down (Gracefully shutdown)
2015 Jul 20 23:04:04 mds9513 %PORT-5-IF_DOWN_NONE: %$VSAN 10%$ Interface port-channel 200 is down (None)
2015 Jul 20 23:04:04 mds9513 %PORT-5-IF_DOWN_PORT_CHANNEL_MEMBERS_DOWN: %$VSAN 10%$ Interface port-channel 200 is down (No operational members)

The "last changed" timestamp on the individual ISL port is not updated:

mds9513(config-if)# sh int fc3/1
fc3/1 is trunking
    Hardware is Fibre Channel, SFP is short wave laser w/o OFC (SN)
    Port WWN is xx:xx:xx:xx:xx:xx:xx:xx
    Peer port WWN is xx:xx:xx:xx:xx:xx:xx:xx
    Admin port mode is auto, trunk mode is on
    snmp link state traps are enabled
    Port mode is TE
    Port vsan is 10
<Snip>
    Belongs to port-channel 200
 Trunk vsans (admin allowed and active) (10)
    Trunk vsans (up)                       (10)
    Trunk vsans (isolated)                 ()
   Interface last changed at Sun Jul 19 20:24:36 2015   ++++ No time change updated.

However, the logical port-channel 200 "last changed" timestamp is updated:

mds9513(config-if)# sh int po200
port-channel 200 is trunking
    Hardware is Fibre Channel
    Port WWN is xx:xx:xx:xx:xx:xx:xx:xx
    Admin port mode is auto, trunk mode is on
    snmp link state traps are enabled
    Port mode is TE
    Port vsan is 10
    Speed is 4 Gbps
Trunk vsans (admin allowed and active) (10)
    Trunk vsans (up)                       (10)
    Trunk vsans (isolated)                 ()
Member[1] : fc3/1
    Interface last changed at Mon Jul 20 23:04:10 2015 ++++ Updated Last changed time.

This is by design.

Cisco confirmed that once an interface is added to the port-channel, it becomes part of the port-channel and is combined into one aggregate logical link entity. Therefore, the "last change" timestamp should be checked on the logical link (port-channel) entity, not on the physical FC interface.

The individual port flaps are documented only in the "show logging log" output.