Why QCI introduced in LTE

Question

LTE provides different QoS for a given application by putting it into the different bearer. each bearer has its own QCI (QoS Class Identifier) which introduce a particular service for a particular application. Now the question is why QCI got introduced in LTE i.e. what was the problem with earlier approach.

Answer 1

LTE is purely designed to provide IP based services. IP packet header has Type of Service(ToS), which vary from service to service. It means when an IP packet received at PGW from external world or internet. PGW has to maintain its ToS parameters. In order to achieve this Type of Service for an ip packet, LTE network has defined QoS Class Identifier (QCI). Each QCI has different packet loss/delay tolerance. So according to Type of Application is being used by an UE, LTE network associates Application traffic through a bearer, which can meet its ToS.

Comments

What could be the possible issue if QoS is used in place of QCI in this case.