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TRUNKING issue between Cisco 3850 & Brocade VDX 6740.

JohnCameron
Level 1
Level 1

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.

1 Accepted Solution

Accepted Solutions

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.

View solution in original post

22 Replies 22

mattjones03
Level 1
Level 1

Hi

 

Im unable to open the attachment.

 

Could you output the contents in your reply?

 

 


@mattjones03 wrote:

Hi

 

Im unable to open the attachment.

 

Could you output the contents in your reply?

 

 


Hi MattJones,

Below are the output's as requested:

 

Cisco

3850-01#sh run int te 1/0/1
Building configuration...

Current configuration : 107 bytes
!
interface TenGigabitEthernet1/0/1
 switchport mode trunk
 channel-group 10 mode active
end

3850-01#sh run int te 2/0/1
Building configuration...

Current configuration : 144 bytes
!
interface TenGigabitEthernet2/0/1
 switchport trunk allowed vlan 2,203
 switchport mode trunk
 channel-group 10 mode active
end

3850-01#sh run int po 10
Building configuration...

Current configuration : 142 bytes
!
interface Port-channel10
 description Link to Brocade-Stack 1/0/21, 2/0/21
 switchport trunk allowed vlan 2,203
 switchport mode trunk
end

Brocade

VDX1# sh run int te 1/0/21
interface TenGigabitEthernet 1/0/21
 channel-group 10 mode active type standard
 no fabric isl enable
 no fabric trunk enable
 lacp timeout long
 no shutdown
!
VDX1# sh run int te 2/0/21
interface TenGigabitEthernet 2/0/21
 channel-group 10 mode active type standard
 no fabric isl enable
 no fabric trunk enable
 lacp timeout long
 no shutdown
!
VDX1# sh run int po 10
interface Port-channel 10
 vlag ignore-split
 switchport
 switchport mode trunk
 switchport trunk allowed vlan add 2,203
 no switchport trunk tag native-vlan
 no spanning-tree shutdown
 no shutdown
!
VDX1#

Many thanks.

Hello

Never configured a barcode switch howerver looking at the cli it simlar to cisco what I did notice on the LAG of the barcode is you have unttagged the native vlan - no switchport trunk tag native-vlan -  which okay but not specifed the native vlan. which seems to suggest that default vlan isnt specifed even though it should default to vlan 1

 

Your could try this:


interface Port-channel 10
switchport trunk native vlan 1
no switchport trunk tag native-vlan

 

 

on the cisco

interface TenGigabitEthernet1/0/1
switchport mode trunk
channel-group 10 mode active
end

interface TenGigabitEthernet2/0/1
switchport trunk allowed vlan 2,203
switchport mode trunk
channel-group 10 mode active

 

These are not correct suggest defaulting both physical interfaces and remove the PC and recreate ftom scratch:

L2 etherchannel
1) default physical interfaces (if possible)
2) configure port-channel in physical interfaces
-- port-channel will be created automatically

3)create trunking encapsulation or access port mode directly in port-channel interface
4)enable physical interfaces "no shut"

 

 

res

Paul


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul


@paul driver wrote:

Hello

Never configured a barcode switch howerver looking at the cli it simlar to cisco what I did notice on the LAG of the barcode is you have unttagged the native vlan - no switchport trunk tag native-vlan -  which okay but not specifed the native vlan. which seems to suggest that default vlan isnt specifed even though it should default to vlan 1

 

Your could try this:


interface Port-channel 10
switchport trunk native vlan 1
no switchport trunk tag native-vlan

 

 

on the cisco

interface TenGigabitEthernet1/0/1
switchport mode trunk
channel-group 10 mode active
end

interface TenGigabitEthernet2/0/1
switchport trunk allowed vlan 2,203
switchport mode trunk
channel-group 10 mode active

 

These are not correct suggest defaulting both physical interfaces and remove the PC and recreate ftom scratch:

L2 etherchannel
1) default physical interfaces (if possible)
2) configure port-channel in physical interfaces
-- port-channel will be created automatically

3)create trunking encapsulation or access port mode directly in port-channel interface
4)enable physical interfaces "no shut"

 

 

res

Paul


Hi Paul,

Thanks for your reply.

I've just ssh to the Cisco switches and I confirm that I the individual ports are configured correctly, I made a mistake when copying the text above and below is the correct config:

3850-01#sh run int te 1/0/1
Building configuration...

Current configuration : 131 bytes
!
interface TenGigabitEthernet1/0/1
 switchport trunk allowed vlan 2,203
 switchport mode trunk
 channel-group 10 mode active
end

3850-01#sh run int te 2/0/1
Building configuration...

Current configuration : 131 bytes
!
interface TenGigabitEthernet2/0/1
 switchport trunk allowed vlan 2,203
 switchport mode trunk
 channel-group 10 mode active
end

3850-01#sh run int po 10
Building configuration...

Current configuration : 142 bytes
!
interface Port-channel10
 description Link to Brocade-Stack 1/0/21, 2/0/21
 switchport trunk allowed vlan 2,203
 switchport mode trunk
end

In terms of the native-vlan, it was tagged by default and I was doing some testing and changed to not tag to see if that made any difference, but unfortunately it didn't.

 

Sure, I'll specify the native vlan on the config when I'm testing this next. Fingres crossed.

 

Kind Regards,

 

 

Don't know if it would be part of the problem, but I noticed Cisco's t1/0/1 doesn't have the allowed VLAN statement as does t2/0/1 and po10.


@Joseph W. Doherty wrote:
Don't know if it would be part of the problem, but I noticed Cisco's t1/0/1 doesn't have the allowed VLAN statement as does t2/0/1 and po10.

Hi Joseph,

Thanks for your reply.

I've just posted the new (updated) config and you can see all the port config matches.

Kind Regards,

Hi,

 

Thanks for the outputs.

 

Firstly, please could you provide the output to the following command (from the Cisco 3850);

 

'show etherchannel summary'

 

After obtaining the above output, please try updating the interfaces participating in the port-channel to the following mode (on the 3850 side only).

 

channel-group 10 mode passive

 

Please let us know if this makes a difference.


@mattjones03 wrote:

Hi,

 

Thanks for the outputs.

 

Firstly, please could you provide the output to the following command (from the Cisco 3850);

 

'show etherchannel summary'

 

After obtaining the above output, please try updating the interfaces participating in the port-channel to the following mode (on the 3850 side only).

 

channel-group 10 mode passive

 

Please let us know if this makes a difference.


Hi Matt,

Thanks for your reply.

I will add this on my to do list when I'm doing this test again. However, like I said before, I don't really think this is an etherchannel or "LAG" issue. To me it's the Trunking a.k.a Encapsulation which is the culprit here. And, the only reason that makes me believe this is, when the port-channel is in Trunk mode, all the packets are getting dropped, change it to access port and it works like a treat for that VLAN. But, I can certainly test this.

Many thanks.

Mark Malone
VIP Alumni
VIP Alumni

Hi

The config is right on the Cisco side looks good on brocade too  , is the PO forming correctly between the devices

what does the Cisco side how when you check it sports with command show interface t1/0/21 switchport

also does cisco side show it in trunk status , show int trunk  and show etherchannel summary ?

 

is the same problem there when only standalone trunk not in an ether channel ?


@Mark Malone wrote:

Hi

The config is right on the Cisco side looks good on brocade too  , is the PO forming correctly between the devices

what does the Cisco side how when you check it sports with command show interface t1/0/21 switchport

also does cisco side show it in trunk status , show int trunk  and show etherchannel summary ?

 

is the same problem there when only standalone trunk not in an ether channel ?


Hi Mark,

I believe the PO is forming correctly because the ports stays up on both end, however, I would need to double check this next time I'm doing testing on this. It is one of those things, where we have schedule a maintenance window as there's live kit on these VLANs which is not accessible when the existing link is removed. Therefore, I can double-check this during the next testing.

Again, I can gather the results from the above mentioned commands in my next testing.

 

Yes, that's right, it's the same problem with a single link between both end. Hence, this suggested me this was more of a trunking issue than the etherchannel.

 

Would it be easier if I can email you or (post here) the full running-config from both switches and see if that helps? The only weird thing I can see in the Brocade config is that this:

no vlan dot1q tag native

has been issue as the global command whereas am I right in saying that the Cisco's are using dot1q by default?

Also, the native vlan is different on both switches? However, when we originally tested this with our Nortel kit, the native vlan was the same on both (Brocade & Nortel) and it was giving us the exact same results. No traffic passes when the link is in Trunk mode. Therefore, this suggested me that there's something on the Brocade config which is possibly dropping tagged (encapsulated) packets. And, as I mentioned earlier, when the link is in access port for either VLAN, it works. So, we know that VLAN tagging is working, and the fact that when the link changes into a trunk port, then encapsulation is being a bit iffy and probably the brocade's are dropping all the packets. But, that's just what I can make of it. Your thoughts?

 

Kind Regards,

 

native vlan should not be different on both switches , this is the same as cisco as its not tagging vlan 1 by default but if you have changed native on each side you will have issues
also I'm not a dell guy but all the port-channel configs ive checked specify teh native vlan in the po ...switchport trunk native-vlan x


@Mark Malone wrote:
native vlan should not be different on both switches , this is the same as cisco as its not tagging vlan 1 by default but if you have changed native on each side you will have issues
also I'm not a dell guy but all the port-channel configs ive checked specify teh native vlan in the po ...switchport trunk native-vlan x

Hi Mark,

The reason why this is because the brocade's were bought earlier this year as part of the HCI project and they're left with the default native vlan 1 which is NOT best practice, however we have now purchased the new Cisco kit and I'm determined to not repeating this again, therefore all the Cisco kit is configured with a new native vlan.

 

You're correct, you would often see the sw tr native-vlan xx on trunk ports, however the reason why this isn't configured in this instance is because, the brocade's trunk arern't configured with the native-vlan number as well. I have seen this on a post in this Cisco forum where someone else was having a similar issue and it was suggested that you either have it or don't have it on both ends, but as long as both ends are configured the same it should work.

 

Since, I have now tested this with not specifying the native-vlan number, I'll specify this in the next test and record the outcome.

 

Kind Regards,

Hello,

 

on a side note, and I am not sure if this has already been mentioned somewhere in this thread, make sure that both switches are running the same spanning tree mode. The 3850 defaults to PVST+ which is Cisco proprietary and probably won't work well with the Brocade...


@Georg Pauwen wrote:

Hello,

 

on a side note, and I am not sure if this has already been mentioned somewhere in this thread, make sure that both switches are running the same spanning tree mode. The 3850 defaults to PVST+ which is Cisco proprietary and probably won't work well with the Brocade...


Hi Georg,

Thanks for your reply.

I've just checked this and the Cisco switches are in rapid-pvst mode.

 

3850-01#sh span sum
Switch is in rapid-pvst mode
Root bridge for: VLAN0001, VLAN0099
EtherChannel misconfig guard is enabled
Extended system ID           is enabled
Portfast Default             is disabled
PortFast BPDU Guard Default  is disabled
Portfast BPDU Filter Default is disabled
Loopguard Default            is enabled
UplinkFast                   is disabled
BackboneFast                 is disabled
Configured Pathcost method used is short


3850-01#sh span detail
VLAN0001 is executing the rstp compatible Spanning Tree protocol
VLAN0002 is executing the rstp compatible Spanning Tree protocol
VLAN0203 is executing the rstp compatible Spanning Tree protocol

3850-01#sh spanning-tree interface te 1/0/1
no spanning tree info available for TenGigabitEthernet1/0/1
!
3850-01#sh spanning-tree interface te 2/0/1
no spanning tree info available for TenGigabitEthernet2/0/1
!
3850-01#sh spanning-tree interface po 10
no spanning tree info available for Port-channel10
!

 

Whereas Brocades are not even running Spanning-Tree.     free smiley

 

 

VDX1# sh spann
% Error: Spanning-tree is not configured

VDX1# sh spann br
% Error: Spanning-tree is not configured

VDX1# sh spann int te 1/0/21
% Error: Spanning-tree is not configured
VDX1# sh spann int te 2/0/21
% Error: Spanning-tree is not configured
VDX1# sh spann int po 10
% Error: Spanning-tree is not configured

VDX1# sh spann vl 2
% Error: Bridge is not configured as PVST/RPVST
VDX1# sh spann vl 203
% Error: Bridge is not configured as PVST/RPVST
VDX1#

 

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