Connect S5248F to Cisco Catalyst 3850

Question

Hi, thanks for reading.

We are mostly Cisco shop but we recently acquired an S5248F for our new VSAN. At this point I am just trying to link the two switches but for some reason they are not communicating. Any help is appreciated. Currently they are connected via a single Cisco SFP+ DAC cable and the links appears to be up at 10gb on both ends (lights are up, both recognizing the SFP+ cable on show interface). On the S5248F I had to put a port-group to drop the speed to 10gb which was working fine. Usually with Cisco I just set the port as trunk and they connect just fine. Below are snippets of the config on each device's respective interface:

CISCO:
interface TenGigabitEthernet1/1/3
switchport mode trunk

DELL:
interface ethernet1/1/1:1
no shutdown
switchport mode trunk
switchport access vlan 1 <-- can't remove this
flowcontrol receive off

I probably just missed something dumb on my end but this is my first Dell switch so I hope you understand Thanks for your help!

Dell-DylanJ · Answer

Hello,

VLAN 1 would be the native VLAN from trunk mode to catch untagged traffic. I believe you can change it with "switchport trunk native vlan XXX", but not outright remove. Linked below is the documentation page for the switch. It's got a bunch of resources that you may find useful as reference material. If you're switch is running OS10, you might give page 257 a look. It's going through setting up in a way that may help.

https://dell.to/3m7g80T

viswhiz · Answer

Hi,

Thanks for your reply. The switchport trunk native vlan XXX is not really my question, I was just pointing out that on Cisco it can be removed but not on OS10. I believe that config is ignored anyway when on trunk mode, as it is on Cisco (but I'm not sure on Dell). You mentioned page 257 but there are a lot of PDFs in there I'm not sure which one you were referring to. I have gone through this documentation before a bit on my search for solution but I could not find anything helpful other than I already did what it says I should do and it should work but it still doesn't.

Regards,

DELL-Erman O · Answer

Hi,

I did research but could not find an article that I can cite as a direct example. I'm not an advanced network expert, but while researching, I noticed this video. it looked pretty good to me https://dell.to/3gAhakP I think it might help you with this explanation. By the way, this is the document that Dylan points to https://dell.to/377HDmq pg 257 pg 258

Apart from these, I came across this topic at https://dell.to/3naQ06n; "Keep in mind Cisco can exchange stp service information between different vendor switches only over vlan 1 when it's configured as native."
There are usually some requirements between switches that must match in terms of MST:
1) MST name
2) MST configuration revision number
3) VLANs mapped to samples

To make both switches part of a common MST zone, a group of switches must share the same configuration attributes.
Understanding Multiple Spanning Tree Protocol https://dell.to/2IJXwX6

Let us know if this helps!

viswhiz · Answer

Hi,

Thanks for your help. We called around a bit and we figured it out. It may have been written somewhere in the manual but we may have missed it, that the Dell defaults to deny all vlan when "allow vlan" is not specified, unlike Cisco. I am not sure but it may also be caused by not using LACP / port-channel. Currently we have port-channel up with the allow vlan xx configured on it, and traffic is finally flowing between the switches in the proper vlans. We intended to use the allow vlan config anyway, we just thought that we did not have to configure it while testing.

I did not touch the MST / STP stuff, both switches are on RSTP as the default I think.

Thanks again for your help.

Networking General

Connect S5248F to Cisco Catalyst 3850

Was this post helpful?