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Synchronous vs Asynchronous
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| What' sthe difference between the two?
Thanks all help is appreciated,
Quantity | |
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| I don't know if this is what your referring to, but.....
synchronous is with the use of precise clocking
asynch. (is the opposite), w/o the use of precise clocking.
anybody else? | |
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| Clocking as far as DCE?
Thanks
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| quote:
Originally posted by hostile:
synchronous is with the use of precise clocking
Right. On a sync line, a station is allowed to start its transmission on a clock tick (not between ticks).
quote:
asynch. (is the opposite), w/o the use of precise clocking.
Rather, with no clock at all. A station starts transmitting whenever it wants.
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Disclaimer: I do my best to provide accurate information. However, if you take my word for granted, you do so at your own risk! It is always better to double check! | |
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| Okay, I understand the difference now! Thanks. However, would the majority of connection oriented protocols use synchronous line? Still confused about why we choose synch vs asynch.
Thnaks a bunch
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| The "sych/async" and "connection oriented protocols" concepts are unrelated (they're connection-less, so to speak  ).
quote:
Still confused about why we choose synch vs asynch.
Each has its pros and cons. Async must use delimiters to mark the start and end of frames (at the expense of wasted time and bandwidth). Sync must ensure synchronization among stations, which sometimes may be very hard to achieve.
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Disclaimer: I do my best to provide accurate information. However, if you take my word for granted, you do so at your own risk! It is always better to double check! | |
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| What i read in my notes it says, asyncronous lines are used on networks with different Bandwidths 10Mbps lines and 100Mbps, this requires switches to use Memory buffering.
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| Can anyone explain why do we use CSU\DSU ?? Does it provide clocking from what i know??? | |
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Originally posted by sids911:
Can anyone explain why do we use CSU\DSU ?? Does it provide clocking from what i know???
channel service unit/data service unit
A device that performs both the channel service unit (CSU) and data service unit DSU functions. The Channel Service Unit (CSU) is used to terminate a DS1 or DS0 (56/64 kb/s) digital circuit. It peforms line conditioning, protection, loop-back and timing functions. The Data Service Unit (DSU) terminates the data circuit to the Data Terminal Equipment (DTE) and converts the customer's data stream into a bi-polar format for transmission.
works on Layer 1
Basically your modem.
[This message has been edited by adilux (edited 11-27-2000).] | |
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| Asynchronous communication uses start- and stop-bits between data. This defines the timing. For example, two frames of one byte each may be transmitted as follows:
(delay)
[START BIT+8 DATA BITS+STOP BIT]
(delay)
[START BIT+8 DATA BITS+STOP BIT]
(delay)
Synchronous communication uses a defined (e.g., DCE) clock signal to time data transmission.
By the way, two things to recall about these forms of transmission:
1. The delay time in asynchronous communication is variable. (This makes it ideal for things like analog modems, by the way.)
2. Synchronous communication provides higher bandwidth
Lawrence |
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