加州大学部署模式:集中式呼叫处理

集中式呼叫处理模型提供人数绕过网站调用的效率。网站称IP广域网路由,而不是使用PSTN资源。网站呼叫路由的数据网络通常称为人数绕过因为PSTN的收费时避免PSTN电话路由。集中式呼叫处理模型还允许一个公司更有效地利用PSTN电路从利用率和容错的角度。路由在一个IP广域网允许PSTN电话资源集中在总部网站所以公司没有管理和维护门户资源在每个站点。公司选择集中定位应考虑购买至少一个模拟PSTN所有资源FXO PSTN网关资源在每个站点上911紧急呼叫路由(911在美国)。雷竞技比分一个或两个模拟语音端口在每个站点上允许呼叫路由当地公共安全回答问题(PSAP)。电话经理4.2/6.0设备流动特性与游牧用户应该为环境配置。思科紧急应急反应提供了最佳解决方案与游牧用户呼叫路由,但是需要额外的资源。集中式与分布式PSTN电话处理场景资源允许公司支持额外的PSTN呼吁每个站点和节省额外收费),国际长途电话。 We will examine a simple scenario where a company has sites in New York, New Jersey, and Reading, England. Each U.S. site has one PRI to the PSTN and the England site has an E1 to the PSTN. Calls from New York or New Jersey to PSTN destinations in England could be routed over the IP WAN from New York or New Jersey to England, where calls can be routed to the PSTN as a local call. This scenario would avoid the international toll charges normally incurred in routing calls between the U.S. and international sites. The functionality described above is commonly referred to as tail-end hop off (TEHO) or least cost routing (LCR). Centralized call processing with distributed PSTN connectivity also allows resiliency and utilization advantages. If all of the outgoing B channels of the PRI in New York are utilized, CUCM can route additional calls across the IP WAN to New Jersey where the additional calls are routed to the PSTN. If the PRI in New York went down, all outgoing PSTN calls could be routed through the New Jersey PRI utilizing the IP WAN. If the IP WAN goes down in a centralized call processing model, the Cisco IP phones at the branch locations will start power cycling. The Cisco IP phones rely on CUCM to remain registered. Cisco IP phones send keepalives to CUCM every 30 seconds by default. If 3 keepalives are not responded to, the Cisco IP phones attempt to register to the other CUCM servers in the Call Manager group that is part of the phone configuration file. The Cisco IP phone will attempt to register with the SRST (survivable remote site telephony) router or switch after all CUCM servers are attempted. SRST is Cisco IOS code in the Cisco router that allows the Cisco router to provide call routing functionality. The Cisco IP phones register with the SRST gateway. The number of Cisco IP phones that can register with the SRST gateway is limited by the router hardware at the site. The 1751 router can only accommodate 24 Cisco IP phones, but the 3845 router can accommodate up to 240 phone registrations. The SRST administration guide includes details of how many phones and directory number are allowed for each router. The administration guide includes the details of SRST configuration. SRST configuration details are also covered in the Global Knowledge Cisco GWGK class. The next blog will continue our conversation of centralized call processing. REFERENCES: CUCM 7.x Solution Reference Network Design (SRND) Guide: http://www.cisco.com/en/US/netsol/ns818/networking_solutions_program_home.html www.cisco.com/go/srnd SRST 7.0 Administration Guide http://www.cisco.com/en/US/docs/voice_ip_comm/cusrst/admin/srst/configuration/guide/srstsa.html