For practical network installations, an eNodeB would be connected to SGW via some IP router. Similarly there can be IP router connection between SGW and PGW.
How is End-to-End QoS maintained between these routers?
Because as I see in specs, the QCI value is transmitted in GTP-C signalling messages between S5/S8, S11 interface: based on that QCI & other QoS parameters, the bearers are defined & GTP-U tunnels are made.
But, for in-between routers, how is QoS guaranteed?