可生存的远程网站电话

可生存的远程站点电话（SRST）是Cisco Unified Communications Manager（CUCM）呼叫处理备份机制，允许Cisco IP电话注册到Cisco路由器。SRST模式下的Cisco路由器提供呼叫安装程序并调用类似于CUCM的拆除服务，但仅在无法访问Cisco Call Manager组中提供的CUCM服务器时的连接。SRST技术广泛用于集中式呼叫处理模型，分支站点没有任何本地呼叫处理能力。Cisco IP电话在分支位置，在广域网（WAN）链接上用CUCM寄存器。分支站点Cisco Phones的所有呼叫设置和调用拆除函数均通过WAN链路进行。呼叫设置并调用拆卸（呼叫控制）带宽要求是良性的（在1Kbps下）。CUCM 7.x SRND的表3-12建议依赖于站点的用户数量的呼叫控制带宽量。如果CUCM和分支站点之间的WAN连接丢失，Cisco IP电话将在Cisco IP电话的“设备池配置”中，将其重新注册到其SRST参考。Cisco IP电话每30秒向其主CUCM服务器发送TCP Keekalive，默认情况下。如果错过了3个keepalives，则思科IP电话将在呼叫管理器组配置中重新注册另一个CUCM服务器，并在没有可用CUCM服务器的情况下尝试使用SRST参考注册。 The SRST failover process occurs faster if there is an active event on the Cisco IP phone device (e.g. Cisco IP phone was taken offhook). The SRST reference can be configured to the default gateway of the DHCP scope or an administratively defined IP address. In many deployments, the default gateway of the site is the only router(s) at the branch location. The default gateway of a branch location may be a virtual IP address shared between two Cisco routers using a virtual router redundancy protocol (HSRP, GLBP, or VRRP). As of this writing, the current version of SRST is 7.1. The SRST Administration guide maps SRST release versions to the Cisco IOS version required for the SRST version. In the next blog, we will continue our SRST conversation with the number of Cisco IP phones and directory numbers supported by different router models. Links SRST Administration Guide http://www.cisco.com/en/US/docs/voice_ip_comm/cusrst/admin/srst/configuration/guide/srstsa.html