What is GUTI and IMSI attach

Just found this as a way that someone joined this blog.
Because I always wanted to start like that..   

Dear wanderer..

If you would ask me to put it simple and shallow way, which I'm trying doing right now, I would say:

Difference between those two is very simple and answer to this question is what really GUTI is and why we are using GUTI in general.

So, GUTI (Globally Unique Temporary UE Identity), is used more or less is to hide "real identity" of the subscriber which is called  IMSI. The less you use IMSI the safer you can feel. Period.

Please keep in mind that it's simple and shallow explanation, and that the GUTI is used in more cases than the one mentioned above.

For more info please refer to LTE Attach article as well to article that cover the IMSI TMSI and GUTI topic.

You could be also interested in Combined Attach information

Source:
from my own experience