Fast recovery from database/link failures in mobile networks

An important issue in the design of future Personal Communication Services (PCS) networks is the efficient management of location information. The cur rent IS-41 standard PCS architecture uses a centralized database, the Home Location Register (HLR), to store service and location information of each mobile registered in the PCS network. If the HLR fails, all incoming calls to a mobile from hosts which are not in the same location area as the mobil e are lost. Location updates from mobiles to the HLR are also lost. Once th e HLR is functional it cannot direct calls to mobiles immediately as mobile s could have changed their location during the HLR's failure. Fast recovery from a failure of the HLR is hence important. A link failure in the networ k could partition the network resulting in a loss of location updates from mobiles affected by the failed link. We present a new protocol for fast rec overy of the HLR after a HLR failure or an intermediate link failure. The p rotocol does not require use of wireless bandwidth during the recovery proc ess, has a bounded recovery period and is simple to implement making it an appealing choice in the design of future mobile networks. We analyze the pr otocol in order to find a medium between protocol cost and the recovery int erval. We use the protocol to recover from VLR failures. We then use the pr otocol to recover from database failures in a distributed database architec ture. (C) 2000 Elsevier Science B.V. All rights reserved.