| A | B |
|---|
| How did Cisco alter the HDLC encapsulation to allow a single link to carry multiple protocols? | Added a type field to identify the protocol |
| What advantage does the multilink option provide when using PPP? | dtat transmission load balancing possibilities |
| What authentication protocol can be spoofed to allow playback attacks? | PAP |
| How is the MD5 function valuable in authentication? Two answers | Uses a one-way hash function & challenges are unique |
| Which command specifies a link quality over a PPP link? | ppp quality 90 |
| What type of cabling is used to connect a router to a modem? | RS-232 |
| What is an advantage of using time-division multiplexing (TDM) for transmitting data? | Multiple sources can transmit over a single channel & TDM supports the transmission of mulitple Layer 2 protocols from a single source |
| How would you describe the High-Level Data Control Protocol? | provides flow and error control & uses sequencing and acknolwedgements & implementated as a bit-oriented, proprietary protocol |
| ISDN BRI service uses two B channels to send data, voice and video. If the first channel becomes saturated, the second channel can be forward packets. What is the command to allow ISDN to load balance across both links? | Router(config-if)#ppp multilink |
| What describes funcions of the Point-to-Point protocol with regards to the OSI model? | It uses the data link layer to cinfigure such options as error dection and compression & provides a merchanism to mutiplex several network layers protocols & can be configured on both sysnchronous and asynchronous serial interfaces |
| What is a communication protocol of the PPP architecture? | LCP |
| What options do LCP provide? | testing quality of a link & limiting bandwidth & load balancing & prevents frame looping |
| What is needed in order to establish a PPP session between two routers? | send keepalives between the two links &send LCP and NCP frames to negotiate configuration parameters |
| Why use PAP or CHAP protocols? | they restrict access to networks connected by serial and ISDN links |
| Descripe the CHAP protocol. | Exchanges a random challenge number during the session to verify identity & prevents transmission of login information in plain text & disconnects the PPP session if authentication fails |
