Wide-area data communications utilize regional networks transporting IP-over-Ethernet
on fiber. For certain Layer 2 services, a regional implementation of the network
makes limited use of spanning tree protocol on a backbone ring. Learning bridge
operations in switches on associated access rings involve a short default for an
aging timer. For use of Open Shortest Path First (OSPF), the connection of each
access ring to the backbone ring uses a pair of routers with dual links therebetween.
One of these links is bonded to the backbone (OSPF Area 0), whereas the
other link is bonded to the Area of the respective access ring. Also, certain routers
within each regional network form a mini-autonomous system, for boundary gateway
protocol (BGP). The mini-autonomous systems of the regional networks form a confederation.
The network utilizes route reflectors in the mini-autonomous systems. The Internet
carries confederation commands to and from a designated hub.