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New Member

cisco switch trunk to Nortel switch


any one know how to configure dot1q trunk between cisco switche 3560 and nortel bay staxk 5510. kindly help me specially configuration required on Nortel


New Member

Re: cisco switch trunk to Nortel switch

this may not be the best forum for configs on Nortel switches as most of us work on Cisco more than any other vendor.

From Cisco end, you would need something like this:

interface fastE x/y

switchport trunk encap dot1q

switchport mode trunk

switchport nonegotiate

Basically, set the encap to dot1q, enable the port as trunk port and disable DTP negotiations.

New Member

Re: cisco switch trunk to Nortel switch


All you need to do on the nortel end is click on the port you want to use as trunk, go the the vlan tab, select trunk, this will use 802.1q tagging, you must make sure you add the port to all vlans you are using under the vlans config, as they dont all get automatically added like Cisco



New Member

Re: cisco switch trunk to Nortel switch

Don't do, PLEASE don't do it. Been there, done that. One issue you will run into is that Nortel does not support PVST, meaning you need to change your WHOLE LAN spanning-tree setup.

If you are installing a Nortel VOIP system, tell them to take their switches away and install a 3750 stack to run thier VOIP system on.

If you want, reply to this and I will be more then happy to give you a long list of reasons why you do not want to try to hook up a Nortel VOIP phone system to Nortel switches in a Cisco shop. In fact, mention my name to your Nortel tech person and they may even give up there and then (note that I am NOT KIDDING).

New Member

Re: cisco switch trunk to Nortel switch


many thanks for help

i will tell you the case: We have old Nortel network solution ( Switches,Firewalls,IP Telephony) we will migrate Switches only to Cisco 4507R and edges 3560 and we will use the old nortel switches as edges also so we want to configure 802.1q on all switches because we have many VLANS

i wait for your reply


Re: cisco switch trunk to Nortel switch

According to the Cisco documentation this should be possible and supported. See the following link:

STP and IEEE 802.1Q Trunks

The IEEE 802.1Q standard for VLAN trunks imposes some limitations on the spanning-tree strategy for a network. The standard requires only one spanning-tree instance for all VLANs allowed on the trunks. However, in a network of Cisco switches connected through 802.1Q trunks, the switches maintain one spanning-tree instance for each VLAN allowed on the trunks.

When you connect a Cisco switch to a non-Cisco device through an 802.1Q trunk, the Cisco switch uses PVST+ to provide spanning-tree interoperability. If rapid PVST+ is enabled, the switch uses it instead of PVST+. The switch combines the spanning-tree instance of the 802.1Q VLAN of the trunk with the spanning-tree instance of the non-Cisco 802.1Q switch.

However, all PVST+ or rapid-PVST+ information is maintained by Cisco switches separated by a cloud of non-Cisco 802.1Q switches. The non-Cisco 802.1Q cloud separating the Cisco switches is treated as a single trunk link between the switches.

PVST+ is automatically enabled on 802.1Q trunks, and no user configuration is required. The external spanning-tree behavior on access ports and Inter-Switch Link (ISL) trunk ports is not affected by PVST+.

So, this means it should be possible, right? I never tried it though, but if I where you I would give it a go.

One thing you have to ensure is that all 802.1q trunks use vlan 1 as the native vlan for this to work. As said, I never really tested it, so I advise to first test this in a controlled lab environment before trying anything in your live production network.