I am learning about Cisco BGP networking now and came across an interesting situation. In my examples, there was one which suggested that two VLANs were configured on Layer 3 in order to run two BGP sessions. This was done in order to segregate the traffic so the client can run two distinct networks (IP prefixes) off of this ISP.
One of the guys here tried to explain it like this but I feel like I am missing something still:
"A L3 VLAN is a local VLAN only on the port side, whereas the Layer 2 VLAN "spans" an ISP's network, and if bundled together the two VLANs = a hybrid port which can carry L3 and L2 traffic."
I understand inherently VLANs are Layer 2 as they deal with MAC address transparency especially when considering QinQ traffic on an ISP network. What I was hoping someone could explain is how a VLAN (or perhaps a better way to refer to it is to call it a logical connection) on Layer 3 works by using IP rather than MAC addresses.
Thanks in advance.