Highlights of the network

IPv4 layer 3 switches were also used as IPv6 layer2 switches.
configure a special VLAN for the IPv6 segments.
IPv4 and IPv6 LANs can conexist via a single switch.

The IPv6->IPv4 translator was located outside the backbone.
-> the IPv6 bacbone could be used as backup for IPv4 connectivity.

Dual stack DNS forwarder
for IPv6 capable systems that do not support IPv6 transfer of DNS queries and responses.
served as a DHCPv4 server, too.
   <====== IPv4 and IPv6 ====>       <====== IPv6 only ===============>
       ---(1)AAAA qry/IPv4--->       ---(2)AAAA qry/IPv6--->
   HOST                     Forwarder                       DNS server
       <--(4)AAAA rep/IPv4--         <--(3)AAAA rep/IPv6----
       --------------(5) data/IPv6 --------------------->