Building large voip network

Installing and configuring two layer-4 level routers on any Linux or BSD system. After each routel setup 7 Asterisk-based servers and 1 server for MySQL DBs. Each Asterisk will include admin GUI and per-user GUI with accounting functions, fax and phonebook per user. External DB used. 1 Dual E1 PRI per Asterisk using Openvox DE210E board. External SIP trunks used for international calls. Summary of project: 1. 2 Layer-4 routers 2. 14 Asterisks 3. Billing for Asterisk prepayd/postpayd (not A2Billing) 4. System stability Hardware used: 1. 2 Intel Xeon 3070 based servers for routers 2. 14 Intel Xeon 3010 based servers for Asterisks 3. 2 Intel Dual Xeon 5400-series based servers for MySQL 4. Hardware RAID1 per server and two RAID1 per DB server. All will be done within two weeks from starting a work. Project's budget $3000 - $3500