Create New Article

Wiki Search

Personal tools

Point-to-Point Leased Line Implementation

From Proprofs

Point-to-Point Leased Line Implementation

Point-to-Point Leased Line Implementation

To setup point-to-point connection between 2 routers:

1. Assign ip address to each interface (must be in same subnet)

2. Issue no shutdown command.

3. Assign clockrate[bps] command to DCE interface.

Data Link Protocols

HDLCsupports synchronous transmission, default for Cisco routers.
PPPsupports asynchronous transmission, error recovery (not enabled by default).

Synchronous = CSU/DSU must operate at same speed on either end of the link. Allows more throughput than asynchronous. Send frames continuously (idle frames when nothing to actually send).
:Receiver Ready: another name for the idle frames

Asynchronous = no frames sent when idle, requires less expensive hardware.

** Note: **
Routers typically use synchronous connections, modem and end PC use asynchronous

Data Link Protocols

PPP and HDLC Framing Image:Ppp-hdlc.GIF

HDLC and PPP Configuration

interface serial 0/0

encapsulation {hdlc | ppp}

compress[predictor | stac | mppc [ignore-pfc]]

show interfaces -> verifies setup

** Note: **

To remove ppp encapsulation, and revert back to hdlc: no encapsulation ppp

PPP Features

Link Control Protocol: Features of PPP regardless of the L3 protocol used.
: one used per link

Control Protocol: L3 specific protocols (for examples, IPCP)
:-> one used per L3 protocol
:-> Cisco uses additional CP for CDP, called CDPCP

LCP Features

Function LCP Feature Description
Error Detection Link Quality Monitoring (LQM) Take down a link based on % of errors on a link.

Only useful in redundant networks that can afford to take device down.
Looped Link Detection Magic Number Using different magic numbers, routers send to each other. If router receives its own number, detect looped link.
Multilink Support Multilink PPP Load-balanced between multiple links.
Authentication PAP/CHAP Exchange names/password to verify identity.

Looped Link: Bits that the router sends are "looped" back and received by the same router. Router wouldn’t notice, because it is receiving information.

Authentication: Verifying that router x is actually who they claim to be.


Password Authentication Protocol (PAP)

  • Sends clear-text passwords

Challenge Handshake Authentication Protocol (CHAP)

  • Uses Message Digest 5 (MD5) one-way hashing on passwords
  • Passwords themselves never cross the link (random number used)


<<                             Table Of Contents                               Next Page>>>

Top 5 Contributors to this article

UsersArticle Contributions
james 7 contribs
Proprofs 1 contribs

Home  |  Site Map  |  Contact
Copyright © 2005-2014 - Privacy & Terms