Point-to-Point Protocol

 

PPP is a Wide Area Network (WAN) protocol that provides OSI layer 2 (data-link layer) services for router-to-router and host-to-network connections (over synchronous and asynchronous circuits) using a serial interface. It is commonly used by PCs to connect to an Internet Service Provider (ISP) via a dial-up phone line (asynchronous host-to network) or as a WAN encapsulation method between LANs (synchronous router-to-router). PPP is an international, standardized and widely used protocol developed by the Internet Engineering Task Force (IETF). PPP is considered a part of the TCP/IP protocol suite and supports a number of LAN protocols such as IP and IPX and various methods of security authentication such as PAP and CHAP. PPP can be used on various physical media, including twisted pair, fiber or satellite transmission. It uses a variation of High-Speed Data Link Control (HDLC) for packet encapsulation.

Synchronous Serial Ports:

Nearly all Wide Area Network (WAN) links used with Internetwoks are "serial" meaning they transmit bits one after another in a series along a wire or fiber cable. Routers have Synchronous serial ports for WAN connections. They are not the same as the Asynchronous serial connection ports found on PCs and are capable of much higher data rates. Most routers have at least one Synchronous serial port for WAN connection and two Asynchronous serial ports; a Console port for local connection and an AUX port for remote configuration of the router.

 

TCS Assumptions:

• The C.O office router that connects with other C.O. are equip with 5 serial interfaces to facilitate PPP connections
• 3 serial interfaces would be used to establish PPP with the 11 sites/school. Sub interfaces would be implemented. Each interface would be logically divided to 4 subinterface. Each subinterface would be assign to a school.
• 4 serial interfaces would be used to establish PPP with the 2 other C.O. sub interfaces would also be used. Each interface would be logically divided to 2 subinterface. 2 physical interface would be use to connect to a C.O.
• 4 T1 data lines will provide Point-to-Point connectivity between each of the three Regional Hubs 
  (I. Data Center - II. Service Center - III. Shaw Butte School)
• One T1 data line will provide Point-to-Point connectivity from each Regional Hub to each connected site.
• All PPP connections would have T1 rate by default and CHAP as their authentication protocol.

 

Configuration of PPP connections

 

Step 1 Enter interface configuration mode for the desired interface.

 

Router(config)# interface serial x.x

 

Step 2 Configure the interface for PPP encapsulation:

 

Router(config-if)# encapsulation ppp

 

Step 3 Configure the interface for PPP Authentication (CHAP)

            Router(config-if)# ppp authentication chap

Router(config-if)# ppp chap hostname

Router(config-if)# ppp chap password