Hi,

Can you private message me the service tags, so we can get some additional information? Is spanning-tree enabled on the upstream switch? It sounds like there is a loop somewhere. Did you use the mlag configuration guide? http://downloads.dell.com/manuals/common/powerconnect_nx00-usingmlag-whtppr_en-us.pdf Is there any multicast traffic?

Hi Josh,

I will send you the service tags.

Spanning Tree (RSTP) is enabled on everything upstream.

I agree about the loop, but it would have to be somewhere in the two tier MLAGs. Those are the only additions. Everything works fine until I connect it to the upstream, and then it grinds the network to a hault without triggering a RSTP recalculation. 

I did follow the guide, with some modifications for our environment.

There is some limited multicast traffic on the network, but nothing that should be coming into play here. 

Here is the show vpc brief with the upstream disconnected.

I ran the same thing earlier when the upstream was connected, and it was identical other than both VPCs being operational and both local and peer Gi1/0/3 being Up. 

CORE-SWITCH-01#show vpc brief

VPC Domain ID.................................. 1
VPC admin status............................... Enabled
Keep-alive admin status........................ Enabled
VPC operational status......................... Enabled
Self role...................................... Primary
Peer role...................................... Secondary
Peer detection admin status.................... Peer detected, VPC Operational
Operational VPC MAC............................ ECF4.BBF4.2401
Operational VPC system priority................ 32767

Peer-Link details
-----------------

Interface...................................... Po1
Peer-link admin status......................... Enabled
Peer-link STP admin status..................... Enabled
Configured VLANs............................... 1,10,15,20,25,30,40,45,50,99
Egress tagged VLANs............................ 10,15,20,25,30,40,45,50,99

VPC Details
-----------

Number of VPCs configured...................... 2
Number of VPCs operational..................... 1


VPC id# 11
-----------
Interface...................................... Po11
Configured VLANs............................... 1,10,15,20,25,30,40,45,50,99
VPC interface state............................ Inactive

Local Members        Status
-----------------    ------
Gi1/0/3              DOWN

Peer Members         Status
----------------     ------
Gi1/0/3              DOWN

VPC id# 60
-----------
Interface...................................... Po60
Configured VLANs............................... 1,10,15,20,25,30,40,45,50,99
VPC interface state............................ Active

Local Members        Status
-----------------    ------
Te1/0/1              Up
Te1/0/2              Up

Peer Members         Status
----------------     ------
Te1/0/1              Up
Te1/0/2              Up


CORE-SWITCH-01#

Can you do a pastebin of the output from show vpc brief? If you do show interfaces are any of them shutdown due to the broadcast storm? We can try enabling BPDU guard and storm-control broadcast to see if that helps.