Solved: TRUNKING issue between Cisco 3850 & Brocade VDX 6740. - Page 2

JohnCameron · ‎10-17-2017

Hi to all the Cisco Experts & Geniuses,

Can I please pick your brains on this slightly frustrating issue I have been having for months which has even been escalated to Brocade support but no one is able to find anything wrong with it at all.

The issue seems to with setting up a TRUNK between the Cisco 3850 stack and a Brocade VDX 6470 stack. A simple TRUNK is causing a major issue and placed the whole project ON-HOLD.

The issue is, when I'm trying to setup a trunk between these 2 switches so that it can carry traffic for 2 or more VLANs, NO TRAFFIC passes. When the Cisco port is configured as an access port for VLAN A, it works and vice versa for VLAN B. I can switch between both VLAN A & B in access port on the Cisco switch, both works but only 1 at a time and NOT simultaneously. Change the port to TRUNK port, both VLANs stop working.

Now, this is very criticial project but it has came to an hault as we are unable to talk to both VLANs therefore, I was hoping to see if anyone can shed some light on this or share any past experiences? Surely, this cannot be that hard?

Attached is the port config from both Cisco & Brocade switches. The way it stands right now, this config doesn't work meaning, we are unable to communicate to host/nodes/servers in both VLANs. However, like I mentioned before, if I change the port on the Cisco switch as an Access Port for either VLAN, we are able to communicate to that VLAN.

I hope, I'd be able to find a solution for this problem. As this has now been on-going for months with no resolution whatsoever and even Brocade support have looked at the Brocade config and unable to find anything wrong with it.

Many thanks.

Georg Pauwen · ‎11-07-2017

That is a problem obviously. Use PVST on both sides and check if that makes a difference...

JohnCameron · ‎11-14-2017

@Georg Pauwen wrote:

That is a problem obviously. Use PVST on both sides and check if that makes a difference...

Hi Georg,

Thanks for your reply.

I understand that the Brocade's are not running STP, however, to me this doesn't matter "in this situtation" because we're unable to setup a trunk between the two stacks, STP isn't blocking the links or putting them in err-disabled mode. The link stays up. Hope this make sense?

Kind Regards,

Matt Delony · ‎11-07-2017

The STP state on 3850 side doesn't look good. It's a little concerning that there is no STP info available for these ports. Po10 needs to have vlans 2 and 203 in a forwarding state before communication between cisco and brocade devices can occur. If Brocade side is not running STP at all, then I would expect 3850 side to be in designated forwarding state for those vlans.

Let's check the following on 3850 side:
Layer 1

what is the status of the physical interfaces?
- show interface T1/0/1
- show interface T2/0/1
- show interface po10

Layer 2

Are VLAN's 2 and 203 defined in VLAN database?
- show vlan
Are member interfaces bundled into port-channel 10 properly?
- show etherchannel 10 summary
What is the layer 2 status of Po10 member interfaces?
- show interface T1/0/1 switchport
- show interface T2/0/1 switchport
What is status of Po10 as a trunk port?
- show interface Po10 trunk

JohnCameron · ‎11-14-2017

@Matt Delony wrote:

The STP state on 3850 side doesn't look good. It's a little concerning that there is no STP info available for these ports. Po10 needs to have vlans 2 and 203 in a forwarding state before communication between cisco and brocade devices can occur. If Brocade side is not running STP at all, then I would expect 3850 side to be in designated forwarding state for those vlans.

Let's check the following on 3850 side:
Layer 1

what is the status of the physical interfaces?

show interface T1/0/1

show interface T2/0/1

show interface po10

Layer 2

Are VLAN's 2 and 203 defined in VLAN database?

show vlan

Are member interfaces bundled into port-channel 10 properly?

show etherchannel 10 summary

What is the layer 2 status of Po10 member interfaces?

show interface T1/0/1 switchport

show interface T2/0/1 switchport

What is status of Po10 as a trunk port?

show interface Po10 trunk

Hi Matt,

Thanks for your reply.

The reason why this isn't looking good right now is because, this isn't a live "link". The Brocade's are talking to the Nortel stack for now until we get this issue resolved and then the "uplink/downlink" will be moved to the Cisco's.

Layer 1

It'll be all down/down for now, since this kit isn't in use.

Layer 2

The VLANs are defined properly and the port-channel is correctly formed with right ports.

I'll post the output of the member interfaces and trunk ports when I'm testing this again.

However, like I mentioned earlier, When the ports, port-channel, ether-channel, LAG, whatever you wanna call it, is in access-port on the Cisco side, it works for that VLAN, whether it is VLAN 2 or VLAN 203. The issue seems to be when we change the port into an "TRUNK" port, neither VLAN works.

Many thanks for your reply. :)

Diana Karolina Rojas · ‎11-07-2017

Hello John,

Did you try this configuration with only one cable? without the port channel?

Regards,

JohnCameron · ‎11-14-2017

@Diana Karolina Rojas wrote:

Hello John,

Did you try this configuration with only one cable? without the port channel?

Regards,

Hi Diana,

Thanks for your reply.

I did indeed, and it's the same result. Therefore, that's why I've been keep saying above that to me it is more of a Trunking issue than a Port-Channel. Hope this make sense?

Kind Regards,

aous.salloum · ‎07-11-2018

Hi,

did you get this to work? I am having the same problem :(

thanks

JohnCameron · ‎07-29-2018

Hi Aous,
I did indeed, turns out there wasn't any issue with the trunks whatsoever. The VX-Rail's configured on the other end of the brocade were not tagging hence when they were receiving the tagged packets they were just getting dropped. Once the change was made on the VX-Rail's everything started working. No changes had to be made either on Brocade or on Cisco switches.
Hope this helps.