How does VLAN trunking operate over mixed networks?

johnifanx98

I understand that VLAN trunking uses trunk port to send updates. In a mixed network, it means connect a trunk port of a switch in a FDDI network to a trunk port of another switch in ether net. If this is the case, I guess, at least a converter is needed to fill up the physical layer between two switches. And anything else?

Forsaken_GA

johnifanx98 wrote: »

I understand that VLAN trunking uses trunk port to send updates. In a mixed network, it means connect a trunk port of a switch in a FDDI network to a trunk port of another switch in ether net. If this is the case, I guess, at least a converter is needed to fill up the physical layer between two switches. And anything else?

This is not an easy question. Basically, you can't connect a FDDI port to an ethernet port and expect them to trunk, no converter will do it, as the layer 2 frames are entirely different (for exampe, FDDI supports frame sizes that ethernet does not). You can bridge the two networks together with a device (which is essentially what anything labelled a converter will do), but trunking gets more complicated, and the solution depends on your topology, available equipment, and addressing scheme (addressing scheme because I wouldn't trunk if at all possible, I'd route between two different layer 2 types, it's far less of a headache)

johnifanx98

Forsaken_GA wrote: »

This is not an easy question. Basically, you can't connect a FDDI port to an ethernet port and expect them to trunk, no converter will do it, as the layer 2 frames are entirely different (for exampe, FDDI supports frame sizes that ethernet does not). You can bridge the two networks together with a device (which is essentially what anything labelled a converter will do), but trunking gets more complicated, and the solution depends on your topology, available equipment, and addressing scheme (addressing scheme because I wouldn't trunk if at all possible, I'd route between two different layer 2 types, it's far less of a headache)

I'm just quoting Lammel's "CCNA fast pass". It says,

Here is a list of some of the benefits VTP has to offer:
VLAN trunking over mixed networks, such as Ethernet to ATM LANE or even FDDI.

From the VTP definition I cannot figure out how this benefit is offered. So I thought I missed a lot to fill this gap...