01-15-2018 11:43 AM - edited 03-01-2019 01:24 PM
Hello Guys,
In a scenario with two different switching domains and I need to connected a UCS to both of them, normally I would use vlan-manager to trunk only specific vlans to each uplink.... Nevertheless I have the following questions:
1. what happens to "vlan 1" ?
2. I know that vlan-1 is mapped to both uplinks, but what uplink gets elected to process broadcasts ?
Thanks in advance,
Bruno Fernandes
Solved! Go to Solution.
01-17-2018 10:18 PM - edited 01-17-2018 10:23 PM
Since Vlan 1 is automatically assign on all Uplinks it is not usable for productive traffic in a disjoint Layer 2 configuration. The DR election is random and there is no preemption in case of a link failure.
01-16-2018 09:03 AM
The link below should help to clarify this:
So the answers in order would be:
1) VLAN 1 is implicitly present on all uplinks.
2) VLAN 1 will be assigned a designated receiver (DR) in an identical manner to all other VLANs present. The DR is the port that will handle all broad/multicast traffic. If you wish to view the DR for any given VLAN the command below is what you'll need to run from with NXOS of each FI.
show platform software enm internal info vlandb id <uint>
Thanks!
01-16-2018 10:57 PM
That's why we preach since decades not to use Vlan 1 (nor Vsan 1) for production.
01-17-2018 01:21 AM
01-17-2018 01:26 AM
01-17-2018 10:18 PM - edited 01-17-2018 10:23 PM
Since Vlan 1 is automatically assign on all Uplinks it is not usable for productive traffic in a disjoint Layer 2 configuration. The DR election is random and there is no preemption in case of a link failure.
01-18-2018 02:45 AM
Hi Lukas,
That's what I was suspecting, that fact is not very clear on documentation at least for vlan-1
Thanks,
Regards,
Bruno Fernandes
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