Is there a valid way to have a port "a0a" with MTU 9000 and tagged VLAN 50 with MTU 9000... then have the a0a port in the default broadcast domain with MTU 1500? It does complain a lot when you do it, but is there a way to do this?
"error: Cannot change the MTU of port "a0a" to be less than the MTU of any VLAN it hosts."... I don't think there is a way arround this, but just asking... maybe I have overseen something... And BTW... would it be terrible to set a CIFS lif to 9000 ? Even though the clients have 1500 set? 😉
#Broadcast domain issue... can it be fixed?
void plume
tranquil flame
Hrmm. Reading into this you may have this configured in a way it shouldn’t be.
You should never be using the native vlan as a tagged vlan at the same time. All switch vendors have known and unfixable bugs relating. Worst cases I think the switch reboots?
You should change the native vlan on a0a to something not used (999?, make sure it’s defined on the switch).
I tend to place all ifgrps into the same broadcast domain and rename it: DoNotUse
Then use tagged vlans for everything
What’s your end goal?
Setting to 9000 should not affect for cifs so long as the Netapp switch connection is already set to 9000(which it is).
Are you simply trying to do mgmt over a0a?
tulip shadow
You can have VLANs with smaller MTU than the physical ports (native VLAN) but not the other way round. e.g. a0a with MTU9000 and a0a-1234 with MTU 1500 works
void plume
Hrmm. Reading into this you may have this configured in a way it shouldn’t be.
...
I am totally aware that it's not great 🙂 It's just that for some reason the customer is tagging vlan 1 on some devices... and also running the default vlan as vlan 1... For some reason their old HPE Aruba switch seems OK with it.. but when connecting their new Nexus switches, it's another matter... its like "either/or"... you can change the default vlan to something else on the Nexus., but I cannot get it to work with both tagged vlan 1 and vlan 1 as default vlan.. it's a mess 🙂 I am now in the process of changing this, so that everywhere they tag vlan 1, we change it... But regarding the issue described I think I will just run with jumbo frames for CIFS... I guess you are right that as long as the client isn't using larger frames than the switch/netapp can handle we should be OK... 🙂
void plume
You can have VLANs with smaller MTU than the physical ports (native VLAN) but no...
Yep we do that alot.. and works fine.. just not the other way arround 😉
charred tartan
I am totally aware that it's not great 🙂 It's just that for some reason the cu...
Can you post the config of the nexus switch for the NetApp ?
void plume
interface port-channel14 description ** a20-02 e4c switchport mode trunk switchport trunk allowed vlan 1,50,600 spanning-tree port type edge trunk mtu 9216 vpc 14
same on the other switch ofcause... and the "sh vpc" shows it's up...
charred tartan
`interface port-channel14
description ** a20-02 e4c
switchport mode trunk
...
Cool, on that config native would be 1, and as it's allowed in the trunk list it will also accept tagged vlan 1 from what ever is plugged into it.
*On your NetApp, leave a0a with mtu 9000.
*Create a broadcast domain with mtu 1500 i.e. vlan1-broadcast-domain
*Create vlan 1 on a0a which will be a0a-1 and assign the broadcast-domain from above.
*Do the same steps for your vlan 50 but use MTU 9000
If you have all the Default-* broadcast domains that the system creates, you need to remove the ports first for the setup above.
As you mentioned above, if the tagged vlan is not working, change the port-channel to an unused native vlan.
tulip shadow
hmm I'm not sure this is how it works, as that would mean that incoming packets to VLAN 1 would have to be sent twice, once with VLAN Tag 1 and once without... 🤔
charred tartan
hmm I'm not sure this is how it works, as that would mean that incoming packets ...
Yeah I would change the port-channel to switchport trunk native <some unused vlan> and keep vlan 1 tagged
tulip shadow
yeah that would be better I agree