An architecture for differential services

Van Jacobson (LBL) presented an architecture for differential services. Some design constraints for this are:

• Scaling: the Internet has nine orders of magnitude heterogeneity in some areas. It is necessary to push all state to the edges of the network, and force all per-conversation and per-transaction traffic to be done at the edges.
• This suggests that the ToS indication must be carried in the packet, since a signalling protocol won't scale
• Administrative diversity and very high speed switching, argue for simple semantics of that ToS indication

The diversity of the Internet, in addition to it's heterogeneity, causes many problems. Packets cross many administrative domains and all those domains must agree to treat some traffic as special. This is complex since those domains don't trust each other, and so multilateral agreements won't happen (one must use a web of bilateral agreements). The provision of differential service must not requie extending trust across administrative boundaries.