Help compatible between vlan 1 on juniper and cisco wwith spanningtree

[tran trong nghia]

Dear Cisco!

so we have a situation about configuration between cisco and juniper.

Cisco we use: WS-C4506

Juniper we use: EX8208

we have to connect 2 switches to do CORE layer for our network.

so we use 2 function on this switches:

+  Spanning Tree: we use VSTP on Juniper and Rapid pvst on Cisco 4506

And we see on vlan 1; if we set vlan 1 on juniper EX8208 is root bride ( vlan unit 1) then cisco 4506 can't see root bridge on Juniper and C4506 is still root bridge for vlan 1 on its

Then we change C4506 is root bridge for vlan 1 then okie: juniper EX8208 can see C4506 is root bridge vlan 1

+ VRRP: We set C4506 is master vrrp for vlan 1

With these configuration, we see:

+ switch layer 2 in this network using vlan 1 to manage, then go to C4506.

+ we have to create route 0.0.0.0/0 on C4506 to EX8208 then we can ping all switch.layer 2

  If we delete this route then we can't ping all swicth layer 2

WE don't know why Ex8208 can't work with C4506 on vlan 1?

Could you please help us solve this situation?

Thanks!

[Georg Pauwen]

Hello,

the issue is caused by the fact that (R)PVST is Cisco propietary, and the Juniper EX switch does not process the BPDUs correctly, causing the root bridge to flap between the Cisco and the Juniper.

Check the link below, I cannot access the Juniper website for  PR683829, but the issue seems to be resolved in 10.4R7; 11.1R6; 11.2R3; 11.3R2:

https://kb.juniper.net/InfoCenter/index?page=content&id=KB22111

[tran trong nghia]

Dear Paul!

Thanks for updating information!

So with VLAN 1 i'm using command "native vlan 1" on Juniper to vlan 1 on juniper then we can ping vlan 1 on Cisco

Same you said we should upgrade Juniper to fix this error?

So you think we can create new vlan id  to manage all switch on this sytem?

Thanks!

See you soon!

[paul driver]

Hello

From a Cisco perspective the connection to a Non Cisco switch would be seen by stp as a CST and vlan 1 should be allowed across 

On the Juniper what's the native vlan and do you have the same vlan added to the trunk interconnected to the Cisco?

Res

paul