multi-VLAN access port

aocferreira

Hello,

I was trying to know a little bit more about this concept, but couldn't find any good info.

What's the real purpose of this multi-VLAN access port ? In what situations is this used ?
What's the difference on having a multi-VLAN access port with vlans 10,20 and having a trunk link with allowed vlans 10,20 ?

In case you have any good documentation on this, please let me know.

Thanks,
André.

lrb

You can have a voice and a data VLAN associated with a switch port if you are connecting to a Cisco IP phone (which in turn has a PC connected to it) and use CDP or LLDP-MED with the network policy TLV to tell the phone how to handle voice and data traffic over the same link (including QoS)

OfWolfAndMan

Like Lrb said, you can configure a VLAN for a computer and a VoIP phone and they will both run fine off of one link from the wall port, you connect it to the phone with the label "sw" on the back and from the phone one the port labeled "PC" you connect the cable to the PC. If the switch coming off of your devices supports PoE (Power over Ethernet) they can support power on the phone without having to plug up an AC adapter.

As for the second question, you know what a trunk link is I'd hope. Allowed vlan allows only those specified VLANs over the link, while preventing any traffic from other VLANs over that trunk (Except for the Native VLAN, assuming you didn't suspend it). It's really just a security measure to prevent people from exploiting a compromised local segment of the network.

aocferreira

Hi,

thanks both for your feedback. it makes sense to me now