pstn and core network

[sarahr202]

Hi everybody.

I have seen how an ATM switch is used to further break ip packets into 53 byte cells and these cells are then forwarded using vp/vpi.

I also see ATM network used iat the PSTN core. My question when we ATM switch in PSTN core, are we breaking the pstn voice traffic into 53 byte cells like ip packets into 53 byte cells?

This is my understanding an ATM just break the message into 53 byte cell. It is not concerned with the type of message  It could be voice traffic from pstn traversing over atm network or it could be ip packets.

thanks and have a great weekend.

[Mohamed Sobair · Accepted solution]

Hello Sarah,

Your understanding is correct.

Whether the Payload is normal Packet or Voice Packet, In ATM , the Packet is fragmented into 53 Byte Cell and reassembled back at the destination. The Virtual Path Identifier (VPI)/Virtual Circuite Identifier (VCI) at the ATM Header identifies a unique path for each circuit.

Regards,

Mohamed

[sarahr202]

Thanks Sobair