关于当手机收到CC27时的行为处理补充更新及T3396的引入

爱卫生

  T3396是在3GPP TS24.008 V9.4以后才加入的.这个Timer是控制什么的呢?另外,手机在做PDP上下文激活的时候可能会失败,其中有一个CC为27,代表missing or unknown APN,那UE在收到这个CC27后的处理行为应该是什么呢？
  这里有一个CR做了补充说明。这个CR是在2010年8月23-27日中国西安举行的3GPP TSG-CT WG1第66次会议上由Vodafone提出的。类型为B，代表addition of feature，是最之前规范的补充澄清，使其更清晰，不具有歧义。而不是类型F，代表对之前规范的错误进行纠正。对应的CSR编号为1600，文档编号为CP-110195，可以直接通过google搜索下载。
  影响的版本是TS24.008 V9.3及之前的版本。
  以下是这个CR中的信息。
——————————————————————————————————————————————————————Title: Handling of cause #27 (missing or unknown APN)
Reason for change: 
It was recognized in networks that ME’s for several reasons are not using allowed APN’s to try to establish connections. These ME’s creating unnecessary load in the networks and also possibly unnecessary costs for the user. To overcome that it is proposed to restrict the immediate reconnection to the same APN after a reject cause #27 (missing or unknown APN).

Summary of change: 
If the ME in case of “Unsuccessful PDP context activation initiated by the MS” and “Unsuccessful MBMS context activation requested by the MS”  receives ACTIVATE PDP CONTEXT REJECT message with cause value #27 (missing or unknown APN) the MS shall not try to reconnect to that APN immediately. An additional timer Timer T3396 is introduced and defined.

Consequences if  
not approved: If this change is not approved it cannot be avoided that e.g. wrongly administrated APN creating unnecessary network load and costs for both user and operator.

Clauses affected: 
6.1.3.1.3, 6.1.3.8.2, 9.5.3, 9.5.24, 10.5.7.4a (new), 11.2.3
——————————————————————————————————————————————————————
    简单来说，就是Vodafone做为运营商发现，很多手机用户在上网时经常使用错误的APN，在收到PDP上下文拒绝消息后，仍然不断的去尝试重新用这个错误的APN继续激活。这样不管是对用户还是运营商来说都要消耗额外的资源。因此Vodafone建议，规范要规定，当UE收到CC27后，启动一个新的定时器，即T3396，这个T3396由SGSN 在Activation PDP Context Reject消息中提供给UE。由这个T3396来控制，当UE收到了CC27后，多长时间之内不得重新发起PDP上下文激活请求。以避免无谓的资源消耗。
   因此，这个CR建议在V9.3以后的规范中增加这样一些话（已经被采纳通过了），以下这些话就出现在V9.3以后的规范中。见下面红色的字体部分，都是新加的说明。
If the SM cause value is #27 "missing or unknown APN", the network may include a value for timer T3396 in the ACTIVATE PDP CONTEXT REJECT message.
Upon receipt of an ACTIVATE PDP CONTEXT REJECT message, the MS shall stop timer T3380 and enter/remain in state PDP-INACTIVE.
If the SM cause value is #27 "missing or unknown APN" and
- if the T3396 value IE is included and
- if the time value of the timer T3396 indicates that this timer is deactivated, the MS shall not try to send an ACTIVATE PDP CONTEXT REQUEST message for that APN until the MS is switched off or the SIM/USIM is removed;
- if the time value of the timer T3396 indicates that this timer is zero, the MS may retry to send an ACTIVATE PDP CONTEXT REQUEST message for that APN;
- if the time value of the timer T3396 indicates neither zero nor deactivated, the MS shall start timer T3396 and not try to send an ACTIVATE PDP CONTEXT REQUEST message for that APN until timer T3396 expires, the MS is switched off or the SIM/USIM is removed.
- if the T3396 value IE is not included, the MS may retry to send an ACTIVATE PDP CONTEXT REQUEST message for that APN.
   最后附上这个CR，以供参考。

弗里德姆

看来还是有很多手机没有严格按照协议来执行。