(4500 Quad SUP VSS) One of the Sup in 4500 chassis always in ROMMON mode ?

[vishal agavane]

Hi Team,

Hope you are doing well.

We have 2 nos of 4500 switch with 2 nos SUP in each of the chassis. We have configured VSS after doing VSS my one of SUP engine in both chassis always keep in Rommon mode,  and always need to give boot command in ROMMON mode to boot up!

If possible then please let us know can't we use Quad SUP in 4500 switches without any manual interference?

do we always need to give boot command in rommon mode or there is any other way by using that we can achieve auto switchover on other SUP in the same chassis?

Your reply will be appreciated.

Thanks,
VA

[Reza Sharifi]

Hi,

I think, for the 4500 series that is the correct behavior.  Not sure if there is a new version that support both sup in active/active mode like the 6800 series.

See link:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/15-1-2/XE_340/configuration/guide/config/vss.html#wp1204229

The Catalyst 4500 series switches support dual supervisors in a redundant chassis, which can be configured for SSO or RPR mode. However, when a chassis is running in VSS mode, it supports a second supervisor engine, but only in rommon mode. In-Chassis-Standby (ICS) can not participate in control, management, or forwarding plane functioning. This makes ports on the supervisor engine in rommon mode available for forwarding although it neither participates in any switchover nor provides protection against any failure. In VSS mode, an In-Chassis-Active (ICA) supervisor engine participates in VSS control/ management operation and manages ports on the supervisor engine in rommon mode.

HTH

[vishal agavane]

Hi Reza,

After removing Active SUP from active chassis, entire chassis reboot but alternate SUP in that chassis is remain in ROM mode and we need to give boot command then only alternate SUP engine boots and became Standaby> SUP in VSS. Please let me know does it possible to avoid manual boot command on alternate SUP and whenever chassis reboots alternate SUP also reboot and become standby> sup in the chassis after restart.

Your reply will be much appreciated.

Thanks,

VA

[Reza Sharifi]

Hi VA,

Form the document:

The supervisor engine does not takeover or boot automatically when the ICA supervisor engine fails. A manual boot up is required to make it participate in VSS; it then functions as an ICA supervisor engine.

So, I think at least up to this version (mentioned in the link) you have to manually use to boot command, which to me defeat the purpose of having 4 sups in 2 chassis. According to Cisco, this issue has been fixed in the 6800 series, but of course pending testing.  I  am not in favor of using 2 sups in a chassis if the fail over is not between sups within the same chassis and then between the chassis.

HTH

[vishal agavane]

Hi Reza,

I've observed standby chassis is not sending any Power related alarms to NMS server? i have done debug and observed if any uplink on the standby chassis went down then all related traps sent to configured NMS server but when single power supply failure happened in the standby chassis then no SNMP traps generated hence no alarm reported to NMS server? only Console message appear on the console screen.

Please let me know is this a normal behavior of 4500 switches in VSS mode?? or there is some IOS bug?

VA...

[vishal agavane]

Hi Reza,

Waiting long back for your reply on this issue, I don't know whether it's well know issue to cisco or not, but standby chassis power supply event not sending any snmp traps to cisco prime or other NMS server. Cisco need to be work on this issue and resolve it asap. if this is well know issue or any IOS bug then please suggest IOS which can resolve this issue.

To temporarily resolve this issue i have create event applet based on syslog message as shown below.

 event manager applet powersupply-1_Down
  event syslog pattern "STANDBY:Power supply 1 has failed or been turned off"
  action SNMP snmp-trap strdata ""

 event manager applet powersupply-1_Up
  event syslog pattern "STANDBY:Power supply 1 is okay"
  action SNMP snmp-trap strdata ""

After doing this i am able to received alarm on NMS server with Event Applet name in it and message like "Experimental alarm"...

in our NMS has facility to modify alarm syntax so by using that feature we have customise our alarm but in cisco prime we only receiving alarm Experimental alarms with Event applet name in it. 

I would strongly suggest if this is unknown issue then cisco must release new IOS which will resolve this issue, if that IOS would have support Quad SUP in 4500 then it's would be Awesome :)

Thanks,

[alf]

Hello,

in the meantime I found the following enhancement in the 3.8XE Release Notes:

RPR Mode for Catalyst 4500-E In-Chassis Redundant Supervisors with VSS

With Quad-Supervisor VSS, each chassis in the VSS can now support an in-chassis standby supervisor (ICS) that operates in RPR mode. (IP Base and Enterprise Services)

Did not test this so far, but I think this is a good step forward.

regards

Alfred