Stacking strange behavior

[Julian_Eble]

Hello,

I've 2 X670G2-48x-4q with version 16.1.3.6 patch1-7 and they're stacked each other.

There're two QSFP cables connected in the ports 57 and port 61 ( suppose to be 80G), but after checking the stack-ports some really strange thing comes up.

Stack Topology is a RingSlot Port Select Node MAC Address Port State Flags Speed
---- ---- ------ ----------------- ----------- ----- -----
*1 1 Native 00:04:96:9a:8d:2f Operational CB 20G
*1 2 Native 00:04:96:9a:8d:2f Operational C- 20G
2 2 Native 00:04:96:9a:74:1f Operational C- 20G
2 1 Native 00:04:96:9a:74:1f Operational CB 20G
* - Indicates this node
Flags: (C) Control path is active, (B) Port is Blocked

Why they're connected by 20G?
Why is there blocked ports?

Thanks,

[Henrique]

There is a stack protocol that identify the ring topology and block one stack-port link regardless of any traffic on that.

That blocked port behavior is to avoid broadcast and multicast (blocked by mcast group)

[davidj_cogliane]

Stack port 1:1 should connect to 2:2, at least we always go 2 - 1 through the stack.

[davidj_cogliane]

80/4 is 20gig.

There is a blocked port to prevent a loop, this is normal is all stacks.