Simulating and testing LTE EPC QoS bearers’ supporting features in ns-3
One of the interesting features of LTE networks is ensuring QoS requirements for UEs’ traffic flows. As we discussed in the previous chapter (Chapter 7), to meet QoS requirements of traffic flows, LTE networks establish end-to-end EPS bearers from UEs to P-GW. Based on the QoS requirements of a flow, a unique EPS bearer will be established and is mapped to sub-bearers: UE and eNB (radio bearer), eNB and S-GW (s1 bearer), S-GW and P-GW, (s5 bearer). Radio bearers are helpful at the LTE-RAN level for allocating necessary radio resources to meet the requirements of a QoS flow. Besides, s1 and s5 bearers help to ensure necessary bandwidth requirements at the EPC level. However, the ns-3.36 LTE module supports only the simulation of GBR and non-GBR flows. Moreover, it is assumed that abundant link capacity is available at EPC.
The ns-3 EPS bearers’ simulation has the following limitations:
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