VDX Spanning Tree with VCS and Cisco Config Check

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I have two VDX 6740 switches I inherited when I started here.  They have VCS configured between them.  I'm not exactly sure how VCS works with Spanning Tree but I assume Spanning-tree doesn't need to happen over the VCS enable links.  Right?  The person who originally set these up did not enable spanning-tree according to "show spanning-tree" so I cannot see what spanning-tree looks like on these two vcs links.

But I need to connect these two up to a Cisco Switch that will be running spanning-tree, RSTP to be exact.  I've been looking through docs, but I think I have this correct.  Does this look right?  Seems straightforward except the spanning-tree bpdu mac.  That is kinda funny.  The two links in the config are not the VCS links.  They are some extra 40G ports I have.

# Enable RSTP
protocol spanning-tree rstp
exit

# Setup Interfaces
interface FortyGigabitEthernet 1/0/49
  description Cisco-Switch
  switchport
  switchport mode trunk
  spanning-tree bpdu-mac 0100.0ccc.cccd
  no shutdown
interface FortyGigabitEthernet 1/0/49
  description Cisco-Switch
  switchport
  switchport mode trunk
  spanning-tree bpdu-mac 0100.0ccc.cccd
  no shutdown

Sorry for the kind of newb question.  I don't normally need to administer these switches, they are some oddball corner ones used for storage traffic and I don't have any ones to test on. 
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Keith Wirch

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Posted 1 month ago

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Erik Auerswald, Embassador

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Hi,

the BPDU MAC address is that used by Cisco's Per VLAN Spanning Tree. The name RSTP usually means the proprietary Rapid-PVST+ with Cisco. Depending on the port configuration Cisco will send different BPDUs, some to the standard BPDU destination MAC, some to the Cisco PVST+ MAC.

I cannot tell you the exact configuration you need for your network, because it depends on quite a few details.

I have tested Rapid-PVST+ compatibility between ExtremeXOS and Cisco IOS, and documented that at https://www.unix-ag.uni-kl.de/~auerswal/exos-cisco-rapid-pvstp/. That might help you understand what you need in your network.

Thanks,
Erik

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Yulia Abitbul, Employee

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Hi Keith,

That is correct that ISL links between nodes in VCS cluster should not have spanning-tree configured, VCS cluster has his own loop prevention mechanism 

Best Regards,
Yulia