Bug 2777

Summary:	bearer differentiation after handover
Product:	ns-3	Reporter:	Tom Henderson <tomh>
Component:	lte	Assignee:	Biljana Bojović <bbojovic>
Status:	RESOLVED FIXED
Severity:	normal	CC:	ns-bugs, zorazeali
Priority:	P3
Version:	unspecified
Hardware:	All
OS:	All
Attachments:	Patch for bug 2777

Description Tom Henderson 2017-08-25 09:58:16 UTC

A user (Sahawat Namwanta) provided the following report.

"Hello, I'm using NS-3.26 and face the problem with the bearer differentiation after handover.

When the UEs first attach to the first eNB, the scheduler was able to differentiate between each bearer just fine.
However, when the first handover occurred, the scheduler sees all UEs as the same bearer (NGBR_VIDEO_TCP_DEFAULT)."

Comment 1 Zoraze Ali 2017-08-29 16:44:02 UTC

Created attachment 2909 [details]
Patch for bug 2777

Comment 2 Zoraze Ali 2017-08-29 16:46:14 UTC

The bug was in UeManager::SetupDataRadioBearer (EpsBearer bearer, uint8_t bearerId, uint32_t gtpTeid, Ipv4Address transportLayerAddress) in lte-enb-rrc. The "bearer" parameter contains an updated EPS bearer related specification, which in the current code is not used to update the default m_epsBearer member of drbInfo. Thus the call to AddDataRadioBearerInfo (drbInfo) is saving drbInfo with default bearer QCI into m_drbMap map.  

This map is later accessed by source eNB to retrieve the EPS bearer related info to be included in handover request to the target eNB.

Please find the attached patch which was tested by the reported user and has resolved the problem. 

Kind regards,
Zoraze

Comment 3 Zoraze Ali 2017-08-30 05:57:45 UTC

Fixed in changeset 13053 c4eff6091564