1. We read WAN Protocols in L2 layer is HDLC and PPP. These are used when you have a dedicated serial circuit. So, how will the service provider network infrastructure will be in processing the frames.Will there be any switches or routers in running in PPP or HDLC and not any other protocols.
So,there will be L3 connectivity between the Routers ???? As we are saying L2 WAN Protocols ???
2. Why there is a Need of Frame relay .Is it emerged because of need of one to many connectivity concept which cannot be achieved by PPP and HDLC. Also for Error checking concepts. In what basis we need to choose Frame relay configuration...depends on the Customer router Specification or the available service provider infrastructure.protocols. How come PPP can be used along with Ethernet protocols and we are calling as PPPoE.
Also Frame relay can be enabled with PPP and ATM with PPP. How come 2 L2 protocols can work together.
4. SONET - This can be configured only the end devices have Fibre optic options and also the service provider should have the SONET enabled network in their backbone or it can be converted to any other L2 protocols ?
5. All the L2 protocols are depends on the Interfaces of the Router..Like Ethernet interface means -- BMA Network ..enable ethernet L2 protocol
and if you have serial interface -- then use Frame relay ---- if it P2P ..then use PPP or HDLC..
If you have Fibre optic interface ---then use SONET ?
Finally, Can MPLS can be configured in all type of interfaces.... and also whether both the customers need MPLS enabled routers at their end and also the Service Provider infrastructure ??...