Member Peering LANs
The member peering LANs can be found in various variations. Every IXP has its own policy how this will be done, there is no real 'solution' to that, it's rather a decision an IXP has to make on its own.
Shared unicast/multicast IPv4, unicast/multicast IPv6
A very simple approach is to have all unicast and multicast traffic on the same production VLAN.
Shared unicast IPv4/IPv6 and shared multicast IPv4/IPv6
Some IXPs also decide to have all unicast protocols in one VLAN, and separate all multicast into a separate VLAN.
Shared unicast/multicast IPv4 and unicast/multicast IPV6
Another approach is to separate IPv4 traffic from IPv6 traffic on separate VLANs. This means the Members of the IXP must not necessarily be dual-stack, but have a separate VLAN for IPv6. Also very good (and an easy way) if you want to measure the amount of IPv6 compared to IPv4 traffic in your network.