Mobile 1 - Wireless Links
Wireless links can have variable characteristics, e.g. delay, throughput, loss
Offering hard QoS is hard in general (GSM exception, but wasteful)
GPRS and other wireless links (wavelan) offer shared media
May be able to coordinate QoS via shared media MAC layer management and handoff management (see ISSLL work in IETF) - requires cooperation
Opposite of trend on fixed nets (e.g. shared media LANs moving to switched approaches!)