[j-nsp] Juniper M7i & Cisco 3650 vlan configuration difficulties

Kenneth Mix kmix at transaria.com
Tue Jan 17 12:20:03 EST 2006


Hello Chris,

If this turns out to be the issue, Cisco now allows tagging of the
native VLAN.  Just use the global config command:

vlan dot1q tag native

According to Cisco, the switch will still accept untagged packets, but
will send only tagged packets.

Ken 

-----Original Message-----
From: juniper-nsp-bounces at puck.nether.net
[mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Eric Van Tol
Sent: Tuesday, January 17, 2006 10:11 AM
To: Chris Davies
Cc: juniper-nsp at puck.nether.net
Subject: RE: [j-nsp] Juniper M7i & Cisco 3650 vlan configuration
difficulties

Chris,
I hate these kinds of replies, but it may help nonetheless...

I've not worked with the Cisco 3650, but in my experience with other
Catalyst platforms, such as the 29xx and 35xx, the 'native' VLAN had to
be modified on the Cisco side to some non-extistent VLAN, thanks to
Cisco's VLAN1 designation of 'untagged'.  In Juniper-world (and pretty
much everyone else), there's no concept of an 'untagged' VLAN:

interface GigabitEthernet0/1
 switchport
 no ip address
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 1000
 switchport mode trunk
!

The VLAN1000 is a VLAN that exists solely on the Cisco switch and is not
used for anything at all.  It could possibly be used for a back-end
management VLAN, of course, but cannot be trunked to
non-Cisco-"compliant" devices, AFAIK.

-evt

-----Original Message-----
From: juniper-nsp-bounces at puck.nether.net
[mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Hyunseog Ryu
Sent: Tuesday, January 17, 2006 10:10 AM
To: Chris Davies
Cc: juniper-nsp at puck.nether.net
Subject: Re: [j-nsp] Juniper M7i & Cisco 3650 vlan configuration
difficulties


Since you configured Juniper side as dot1q, you should configure Cisco 
port as dot1q.

Here is the example for Cisco 3650 configuration.

interface GigabitEthernet0/1
  switchport
  no ip adress
  switchport trunk encap dot1q
  switchport trunk encapsulation dot1q
  switchport mode trunk
exit
interface vlan2
   ip address x.x.195.250 255.255.255.252

This will do it.

Hyun


Chris Davies wrote:
> I've got a Juniper M7i and a Cisco 3650.  I need to run vlan-tagging
on
> the interface that connects the two due to another piece of hardware 
> which requires it.
>
> Juniper:
>
>      ge-1/3/0 {
>          description "Aggregate LAN";
>          vlan-tagging;
>          link-mode full-duplex;
>          unit 0 {
>              vlan-id 2;
>              family inet {
>                  address xx.xx.195.249/30;
>              }
>          }
>      }
>
> Cisco:
>
> interface GigabitEthernet0/1
>   no switchport
>   ip address x.x.195.250 255.255.255.252
>
> As soon as I add the vlan-tagging to the gigE port on the Juniper, the
> two units cannot communicate.
>
> I also tried to configure the GigE port on the cisco as
>
> interface vlan 2
>    ip address x.x.195.250 255.255.255.252
> interface GigabitEthernet0/1
>    switchport access vlan 2
>
> However, that also does not work.  Cisco's vlan is an internal 
> designation, not 802.1q.
>
> If I try to turn on 802.1q encapsulation:
>
> #switchport trunk encapsulation dot1q
> Command rejected: Gi0/1 not a switching port.
>
> #switchport encapsulation dot1q
> Command rejected: Gi0/1 not a switching port.
>
> Is there a way to configure a port so that the primary interface
doesn't 
> require vlan tagging, but a secondary interface does?  Or, is there a 
> way to assign two other IPs as VLANS that are not attached to an 
> interface but are able to be reached through a direct IP address?
>
> Thank you.
> _______________________________________________
> juniper-nsp mailing list juniper-nsp at puck.nether.net
> http://puck.nether.net/mailman/listinfo/juniper-nsp
>
>
>
>   


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