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what is the purpose of default bearer in LTE?

+2 votes

Probably is newbie question -
What is the purpose of default bearer in LTE and why this concept is missing in UMTS?

posted Sep 5, 2013 by anonymous

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1 Answer

+1 vote

In LTE, there is a concept of always on IP connectivity. It means even if UE becomes idle after a successful attach with core networ, assigned IP address will be there for UE until and unless it gets detached from network. default bearer is a non-guaranteed bearer. It means even UE gets connected with eNB and Core network. It is not necessary that data should flow through default bearer.

answer Sep 5, 2013 by Vimal Kumar Mishra
Though I am not sure but for me default bearer is there because of voice flows onto datapath in the LTE where as in UMTS it was not.
Usually default bearer is established with QCI 9, which can't serve conversational voice in lte.
Thanks Vimal, I am not sure. I made a guess because it was not there in UMTS, not sure who asked this question but surely this Q needs many upvotes.
Hi Salil , Even in UMTS we had a primary PDP context, Default bearer is similar to the same. Since UMTS had IU-CS and IU-PS separately so the UE can be latched to the network only for voice and sms (IU-CS) and no data, In LTE there is no such concept of CS so if a UE is connected to the network it must have at least one PDN connection. To be more specific , for the UE to be in EMM registered state , it must have a default bearer connection active.
Similar Questions
+1 vote

Which NE stores the details of Default and Dedicated bearer details for all the UE's?

Question:1:- For example, UE1 has 1 default and 3 dedicated bearers. Which NE stores this information and based on what parameters, the bearers are mapped?

Question:2:- When UE is accessing, based on what parameters the bearer will be selected, either Default or Dedicated for will be decided?