EPS 承载

EPS Bearer是下面红色线

更加细节的承载示意图

另外，EPS的承载分为默认承载，和专用承载。

首先看下两种承载的解码结果

他们的不同点在于：

i) Default EPS Bearer :

[if !supportLists]l [endif]Be established during Attach Process

[if !supportLists]l [endif]Allocate IP address to UE

[if !supportLists]l [endif]Does not have specifc QoS (only Nominal QoS is applied).

ii) Dedicated EPS Bearer

[if !supportLists]l [endif]Normally be established during the call setup after idle mode. (but can be established during the attach as well).

[if !supportLists]l [endif]Does not allocate any additional IP address to UE

[if !supportLists]l [endif]Is linked to a specified default EPS bearer

[if !supportLists]l [endif]Have a specific (usually guaranteed) QoS

默认承载有“APN Name”和“PDN type/PDN Address”而专用EPS承载没有，每一个默认承载对应一个APN，专用承载使用默认承载指定的PDN address，其中专用承载的“Linked EPS Bearer Identity”指向对应的默认承载；他们拥有不同的QCI等级。