bllue215的专栏

用户电路的作用是实现各种用户线与交换之间的连接，通常又称为用户线接口电路(SLIC,Subscriber Line Interface Circuit)。根据交换机制式和应用环境的不同，用户电路也有多种类型，对于程控数字交换机来说，目前主要有与模拟话机连接的模拟用户线电路(ALC)及与数字话机，数据终端(或终端适配器)连接的数字用户线电路(DLC)。  

SIP so far support two kinds of procondition QoS (RFC3312, update by RFC4032) & Secure Session (RFC5027). Preconditions intend to ensure minimum possible of session establishment failure. So that, it

Opensips (www.opensips.org) is an well-know open source SIP server which supports TLS.1. Compile opensips and configuration.    There are many material can be referred over the web site about the