MME的NAS 安全算法选择疑惑

weimiao

3GPP 33.401的7.2.4.31有如下描述：

Each MME shall be configured via network management with lists of algorithms which are allowed for usage. There shall be one list for NAS integrity algorithms, and one for NAS ciphering algorithms. These lists shall be ordered according to a priority decided by the operator.
To establish the NAS security context, the MME shall choose one NAS ciphering algorithm and one NAS integrity protection algorithm. The MME shall then initiate a NAS security mode command procedure, and include the chosen algorithms and UE security capabilities (to detect modification of the UE security capabilities by an attacker) in the message to the UE (see clause 7.2.4.4). The MME shall select the NAS algorithms which have the highest priority according to the ordered lists.

我的问题是，如果MME上配置的算法列表 lists of algorithms 和UE上报的security capabilities列表没有交集，MME应该选择什么安全算法？
例如UE上报的 security capabilities里面只有EEA0和EIA0是supported，而MME OAM配置的是EEA1和EIAI,那么MME应该选择什么算法下发给UE呢？

请达人解答。

[ 本帖最后由 weimiao 于 2011-8-29 20:46 编辑 ]