In attach request, UE sends UE network capability which contains the list of security algorithms can be used to enable security between UE and network node. My question is, when UE already knows its supported algorithms then why MME resend the same list of security algorithm to UE in security mode command ? What would be the reasoning behind it ?
UE will share list of security algorithms which were supported by UE in UE Network capability IE. then MME can select some security algorithms based on MME policies which were received in UE Network capability IE and send in security mode command. means, MME may not support all of the security algorithms which were received in UE Network capability.
i want security mode failure cases 1)security capabilities mismatch. 2)security mode rejected,unspecified. ,,,after failure what happening?
What is the significance of UE capability Information at MME ? What decisions are affected based on the UE capability information ?
when mme will change the security keys and send it in ue context modification request message
I found two MME UE S1-AP IDs i.e. MME UE S1AP ID (Mandatory) and MME UE S1AP ID 2 (optional). I got why mandatory one is present but what's use of optional one.
Can someone please explain it ?