RSPAN Issues after replacing core switch with 3850

[mitchell helton]

Good morning!

I have a case open w/TAC and have not made any progress.  It's being escalated by our account manager due to lack of a resolution, but that's neither here nor there.  I figured I'd post here in case it was something simple that we're overlooking.

Our environment consists mostly of 3750 and 2960 switches.  RSPAN worked perfectly until last Summer when replacing our core (3750x) with a 3850.  Since then, RSPAN traffic seems to be dropped by the 3850.  I've done all sorts of troubleshooting with TAC, but so far they've been unable to tell me what the problem is.  They say it works in their lab.

Are there any known issues with the 3850 platform doing RSPAN with 2960/3750?  Is this a bug?  Working as intended?  Any thoughts?  This is on a WS-C3850-48P running 16.3.7.  Thanks so much!

[Mark Malone]

Hi
i dont see any rspan bugs in your version that are known about anyway , link below , one in earlier version
did TAC test with the same version IOS-XE , unless theres a specifc reason you cant you could try a different version , your on the latest and if its a bug it may not have been discovered yet until its passed to the BU to check

is it intermittently dropping traffic or its dropping all traffic ? TAC confirmed config is ok yes and the vlans are definitely forwarded between the switches on the trunks etc

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/16-3/release_notes/ol-16-3-3850.html

[mitchell helton]

Thanks for the reply!

We started on 16.3.6 and upgraded to 16.3.7 due to a bug that was causing reloads when VLANs were modified.  So, the RSPAN has not worked on either of those versions.

We have done packet captures and see the mirrored traffic coming into the switch, but it never egresses to the destination port.  They've looked over my config numerous times and didn't see an issue. They said they tried 3 different versions of code (including the one I'm currently on) and were unable to reproduce.

[Reza Sharifi · Accepted solution]

If they have gone over your config and they cannot reproduce it in their lab and you have tried different software versions than you may have a hardware issue.  Ask TAC to send you a replacement.

HTH 

[mitchell helton]

Thanks for the feedback guys.  My account manager reached out to an engineer colleague of his and suggested we upgrade to the newest version of code.  TAC has not been able to provide me with information showing this is an open caveat, so I have low expectations but am hoping for the best.  I plan on doing the upgrade in a couple of weeks and will post back here with my findings.

Thanks!

[mitchell helton]

I finally did the TAC recommended upgrade and it did not fix my issue.  According to the feature navigator, this should work.  I'm going to open another case w/Cisco and see if I have better luck.  Any other ideas?  Thanks!

[mitchell helton]

This is finally resolved.  Turns out there must've been a hardware defect.  After doing an RMA for the switch, RSPAN is now working as intended.