Data retry场景介绍

本文介绍PDN激活失败或者IP Address缺失时的处理机制。

终端是否会retry？

如何设置data retry timer？

Modem retry还是上层应用发起retry？

• IPV4V6 Fallback

 3GPP TS 24.008 6.1.3.1定义了UE使用IPV4V6 pdp type建PDN失败后，如果网络以#Cause50、#Cause51或者#Cause52 reject掉后，UE应该使用IPV6 or IPV4去retry，这种行为就叫IPV4V6 Fallback。

If the MS requests PDP type IPv4v6, but the operator uses single addressing per PDP context due to interworking with nodes of earlier releases, the network shall override the rPDP type equested by setting the PDP type in the ACTIVATE PDP CONTEXT ACCEPT message sent to the MS to a single address PDP type. In the ACTIVATE PDP CONTEXT ACCEPT message sent to the MS, the network sets the PDP type number to either "IPv4 address" or "IPv6 address" and the SM cause to #52, "single address bearers only allowed" (see subclause 6.1.3.1.1). The MS may subsequently request another PDP context