本文档根据3GPP TS 23.401描述，整理了EPC系统的所有业务流程，并且对其中的各个接口和每个协议字段进行了详细说明。

EPC信令流程与协议分析，4G核心网的中级课程,将深入讲解EPC网络的各种常见及典型信令流程,这些流程主要包括: 附着、TAU、连接管理等；以及EPC网络各种协议详解。

Seagull是一款IMS EPC等信令模拟器，通过脚本配置交互场景，做Diameter SIP H248等LTE协议的压力测试工具。 Seagull is ahttp://gull.sourceforge.net/ free, Open Source (GPL) multi-protocol traffic generator test tool. Primarily aimed at IMS (3GPP, TISPAN, CableLabs) protocols (and thus being the perfect complement to SIPp for IMS testing), Seagull is a powerful traffic generator for functional, load, endurance, stress and performance/benchmark tests for almost any kind of protocol. In addition, its openness allows to add the support of a brand new protocol in less than 2 hours - with no programming knowledge. For that, Seagull comes with several protocol families embedded in the source code: •Binary/TLV (Diameter, Radius and many 3GPP and IETF protocols) •External library (TCAP, SCTP) •Text (XCAP, HTTP, H248 ASCII)