This document summarizes work done to avoid bottlenecks in personal communication service (PCS) networks. It discusses replicating the home location register (HLR) using various strategies to improve reliability and availability. A multi-HLR architecture is proposed with several zone-based HLRs instead of a single HLR. Performance is analyzed and the cost of location updates is estimated for explicit and group de-registration schemes. Results show the group de-registration scheme in the multi-HLR architecture has lower costs than the explicit scheme. The proposed architecture avoids bottlenecks and stale location entries through replication and group de-registration.