The other day I had a query about a roaming network that was sending Bearer Level QoS parameters in the Create Session Request to 0Kbps, up and down rather than populating the MBR values.

I knew for Guaranteed Bit Rate bearers that this was of course set, but for non GBR bearers (QCI 5 to 9) I figured this would be set the to MBR, but that’s not the case.

So what gives?

Well, according to TS 29.274:

For non-GBR bearers, both the UL/DL MBR and GBR should be set to zero.

So there you have it, if it’s not a QCI 1-4 bearer then these values are always 0.