Mega mergers among the nation's largest carriers could mean good news for businesses that buy network-based VPN services.With SBC merging with AT&T and buying BellSouth, the combined entity - called AT&T - will have one of the most extensive and best MPLS networks in the country.According to a recent study by Forrester Research, AT&T pre-merger was the top MPLS provider. BellSouth and SBC were both listed as contenders, not leaders, but the melding of the three will bump them up.This is significant for VPN customers that have many dispersed locations, where before they might have had to cross multiple carriers' networks to reach all sites. That would put a crimp in imposing varying quality of service levels across the VPN for different types of traffic. Most carriers don't yet support each other's QoS schemes, so unless special - expensive - arrangements are made, service quality is lost as traffic crosses network boundaries.With the combination of these three networks, there will be fewer locations AT&T cannot reach from within its own network, so more and more locations will be able to share a corporate QoS scheme.Don't get all excited about this yet. The AT&T being discussed here won't even exist until the latest deal gets governmental blessings and that will take months. Then the technical staffs have to get together to figure out what unified QoS scheme they are going to follow and then they have to implement it. This will take time as well. Changing ownership doesn't remove the actual differences among networks.But AT&T should certainly have the incentive to act quickly on this especially if prodded by its biggest customers.