top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

Why MME will not use Update Location procedure for UEs receiving emergency services?

+1 vote
Why MME will not use Update Location procedure for UEs receiving emergency services?
posted Feb 6, 2015 by Gnanendra Reddy

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button
Please put some context here, could not get the query ??
For UEs receiving emergency services (i.e. emergency attached UEs or normal attached UEs with a UE Requested PDN Connection for emergency services), and if the MME supports emergency services for users in limited service state, the MME  shall proceed even if the Update Location procedure fails (e.g. authenticated users with roaming restrictions or RAT-Type restrictions in HSS).

Here  even if update location procedure fails also MME can serve UE i.e MME not updating UE information in HSS because of emergency services?My question is why MME not performing update location procedure is there any reason ?
Just making a guess -
For an Emergency Attach, UE does not gain the full service right of from the MME so it may not be doing ULR procedure. MME does not even check for access restrictions, regional restrictions or subscription restrictions etc.

UEs that are in limited service state i.e. emergency state, should initiate normal initial attach when they are not already attached to gain the full access and at that time they will initiate the ULR.

1 Answer

+1 vote
Best answer

As per my knowledge, When an UE tries to attach to network with attach type "Emergency", it may not have IMSI. In that case, UE shall include IMEI in attach request. As soon as MME receives this emergency attach request message without IMSI, it would not inquiry to HSS for Authentication-Information-procedure or Update-Location procedure since for both the messages, IMSI is necessary. MME checks with EIR for the validity of IMEI. Once IMEI is authenticated or based on the operator policy response (in case of IMEI authentication failure) , MME proceeds further.

answer Feb 9, 2015 by Harshita