24 feb 2009itcn 1 introduction to computer networking m clements
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24 Feb 2009 ITCN 3 This Week Other ways to login to a router TELNET, Console cable DCE and DTE Serial Data Links Saving router configurations TFTP serverTRANSCRIPT
24 Feb 2009 ITCN1
Introduction to Computer Networking
M Clements
24 Feb 2009ITCN2
Last Week ………
Virtual Week All outstanding work completed Hopefully!
24 Feb 2009ITCN3
This Week
Other ways to login to a routerTELNET, Console cableDCE and DTESerial Data Links Saving router configurationsTFTP server
24 Feb 2009ITCN4
Logging into a router
Packet Tracer is TOO easy In a real situation, logging into a router will need to be
setup as part of configuration Off the shelf, you MUST login via a console cable and
a PC Console cable is often flat, blue and connected to the
RS232 (serial port) of a PC and the Console port of the router
Use a program such as hyperterminal
24 Feb 2009ITCN5
Establishing a Hyperterminal Session
All Cisco routers include an EIA/TIA-232 asynchronous serial console port (RJ-45).
Cables and adapters are needed to connect a console terminal (an ASCII terminal or PC running terminal emulation software) to the console port.
24 Feb 2009ITCN6
Using TELNET to login
TELNET is also commonly used Need to set up the TELNET line on the router 5 TELNET lines possible 0 – 4 Can be configured together or separately Need a TELNET password or no
communication is possible Remember TELNET is insecure
24 Feb 2009ITCN7
Password Configuration
24 Feb 2009ITCN8
Adds, Moves, and Changes
24 Feb 2009ITCN9
Saving your Router Configuration
Can be saved to NVRAM on router Can be saved on a PC Uses Trivial File Transfer Protocol TFTP Must configure a TFTP server on PC first Limited functionality given Always put server root in C:\
24 Feb 2009ITCN10
Using the copy running-config tftp Command
24 Feb 2009ITCN11
Using the copy tftp running-config Command
24 Feb 2009ITCN12
Long distance Data Transfer
Ethernet has limited range so can’t be used Must use another service E.g. modem, frame-relay, ATM Need to change line coding, voltages etc Line converter must be used Can be onboard router or external device Carries our data, but in a different format Translated back at far end of link
24 Feb 2009ITCN13
Crossing Distances
PC works using parallel buses Cannot use parallel for long distances Cable cost increases greatly Skew problems occur Solution is serial i.e. bit by bit
24 Feb 2009ITCN14
Parallel Data Transfer
24 Feb 2009ITCN15
Serial Data Transfer
24 Feb 2009ITCN16
DCE Data Circuit-Terminating Equipment or
Data Communication Equipment A DCE terminates a network circuit Converts bits received from the DTE to the
proper bit encoding for the network DCE provides bit clocking for the DTE DCE equipment includes modems,
CSUs/DSUs and switch interfaces
24 Feb 2009ITCN17
DTE Data Terminal Equipment Strictly the interface between PC parallel
circuitry and a serial device Serial devices: modem, CSU/ DSU Router serial interface is DTE PCs serial port is DTE
24 Feb 2009ITCN18
Identifying DTE and DCE
• DCE always has to be at each end of a long-distance or WAN link
•It converts serial data from PC to line voltages, coding etc used on the long-distance link
24 Feb 2009ITCN19
Serial cablesSerial cables
Each cable has a DCE end and a DTE endEach cable has a DCE end and a DTE end
Clearly marked – do not mix upClearly marked – do not mix up
24 Feb 2009ITCN20
Summary
Login via TELNET or Console cable Setup console & TELNET passwords first DCEs always go in pairs at each end of a long
distance data connection DTE is serial connection on PC/ router Can use a TFTP server to
– save or load configurations– Upgrade IOS version