1 © NOKIA CTXX 4056/1.0en.PPT/20.6.2000/Timo Vakkala

Gb Interface

After the module, the participants will be able to:

Explain how Frame Relay is used in GPRS

Explain parameters in Gb interface

Explain how to modify parameters in Gb interface

2 © NOKIA CTXX 4056/1.0en.PPT/20.6.2000/Timo Vakkala

Gb Interface Transmission

ET

TransmissionNetwork

ET

BSC

TCSM

MSC

Frame RelayNetwork

ET

ET

ET

ET

SGSN

1

2

3

4 © NOKIA CTXX 4056/1.0en.PPT/20.6.2000/Timo Vakkala

Gb Interface Logical Structure

PCU

PCU

PCU

BSC

PAPU

NSE

BVC

FR bearer channels

NS-VC

PCM

5 © NOKIA CTXX 4056/1.0en.PPT/20.6.2000/Timo Vakkala

Gb Interface

• Each PCU represents one Network Service Entity (NSEI)

• Each PCU can be connected to an SGSN via up to 4 Frame Relay Bearer channels

• Bearer channels can be configured in steps of 64 kbit/s

• Each bearer channel carries one to four NS-VCs(Network Service Virtual Connections)

• The NS-VC is a virtual connection between the PCU NSEI and the same NSEI in the SGSN and is configured in steps of 16 kbit/s

6 © NOKIA CTXX 4056/1.0en.PPT/20.6.2000/Timo Vakkala

Gb Example

0 TSL 0 Link Management

1

2

NS-VC = 1 CIR = 160 kbit/s

3

4

5

6

NS-VC = 2 CIR = 224 kbit/s

7

8

9

…