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Home > Archive > CCNP > June 2004 > What is the difference between synchronous and asynchronous interface
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What is the difference between synchronous and asynchronous interface
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| zaza230 2004-06-19, 11:28 am |
| I can't understand the difference between them.
When should we used a synchronous interface ? what is the speed ? ... ???
When should we used a asynchronous interface ? ...
thanks in advance | |
| darthfeces 2004-06-21, 11:43 am |
| synchronous
In general, synchronous (pronounced SIHN-kro-nuhs, from Greek syn-, meaning "with," and chronos, meaning "time") is an adjective describing objects or events that are coordinated in time. In information technology, the term has several different usages.
1) In telecommunication signaling within a network or between networks, synchronous signals are those that occur at the same clock rate when all clocks are based on a single reference clock. (plesiochronous signals are almost but not quite in synchronization and asynchronous signals are those that run from different clocks or at a different transition rate.)
2) In program-to-program communication, synchronous communication requires that each end of an exchange of communication respond in turn without initiating a new communication. A typical activity that might use a synchronous protocol would be a transmission of files from one point to another. As each transmission is received, a response is returned indicating success or the need to resend. Each successive transmission of data requires a response to the previous transmission before a new one can be initiated.
Synchronous program communication is contrasted with asynchronous program communication.
In general, asynchronous (pronounced ay-SIHN-kro-nuhs, from Greek asyn-, meaning "not with," and chronos, meaning "time") is an adjective describing objects or events that are not coordinated in time. In information technology, the term has several different usages.
1) In telecommunication signaling within a network or between networks, an asynchronous signal is one that is transmitted at a different clock rate than another signal. (plesiochronous signals are almost but not quite in synchronization - and a method is used to adjust them - and synchronous signals are those that run at the same clock rate.
2) In computer programs, asynchronous operation means that a process operates independently of other processes, whereas synchronous operation means that the process runs only as a result of some other process being completed or handing off operation. A typical activity that might use a synchronous protocol would be a transmission of files from one point to another. As each transmission is received, a response is returned indicating success or the need to resend. Each successive transmission of data requires a response to the previous transmission before a new one can be initiated.
Synchronous program communication is contrasted with asynchronous program communication. | |
| marathi_mulgaa 2004-06-22, 11:28 am |
| Zaza - Are you studying for the BCRAN? I'm finding Remote Access to be one miserable test to study for. | |
| bdbest 2004-06-29, 4:37 am |
| i did the bcran test last week and fell short of the passing score by 70 points. i could not complete one of the simulation questions
i'm planning to do it real soon. i had a problem with a modem configuration simulation during the exam. i could not get the modem to respond ok after i issued the AT COMMAND.
THE TASK somthing like this:
configure s0/1 for asynchronous communication
set the line speed to 55.7
set flow control to hardware
set the stop bits to one
set line password to cisco
configure loopback address to 10.10.10.1/32
reverse telnet to the modem
issue an AT command, the modem should respond with ok.
my solution:
interface serial 0/1
physical-layer async
exit
line 1
login (this line did not work during the simulation, so i skipped it)
password cisco
speed 55700
stopbits 1
modem inout
flowcontrol hardware
transport input all
exit
interface loopback 1
ip address 10.10.10.1 255.255.255.255
exit
copy run start
telnet 10.10.10.1 2001 (i got error messages when i tried to telnet to the modem, so i could not go beyond this point)
please what are the possible problems with this configuration, could it be i did not issue the "no shutdown" command at the serial interface or does the "async mode interactive" command have to be used? |
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