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help
by Unknown on Dec 24, 2008 |
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Ethernet is a serial bus protocol where many device can send data, if
maximum data size in one packet is not defined , it may be possible
one device will hold the line all time, i think this is the reason ,
IEEE define maximum size of a packet.
-Rahul
----- Original Message -----
From: aramisp at y...
To: ethmac at o...
Date: Fri, 15 Nov 2002 18:21:47 -0100
Subject: Re: [ethmac] =?gb2312?B?aGVscA==?=
Why is the max size of a frame 1500 bytes. Where is this number
determined from. ???????
(or aprox. 1500 bytes)
----- Original Message -----
From: Javier_castillo_villar at y...
To: ethmac at o...
Date: Tue, 23 Apr 2002 11:17:52 +0200
Subject: Re: [ethmac] =?gb2312?B?aGVscA==?=
>
> > You can have various cases. If you are using DIX ethernet standard
> (the windows standard) your length field are not the length of
the
> frame, it´s the type of the frame, if you are using IP over
> ethernet this > field is 0x800 if you are using ARP is 0x806. If you are using > 802.3 the > length type can be lower than the total length of the frame. This
> is
> because the frame are very short and the tx make padding that is
> they
> put character 0x20 to make the frame at least 64 bytes long. > If in your trasmitter the frame it´s longer than 1500 bytes it´s
> an error
> because the IP must know the MTU(maximun transfer unit) of the phy
> layer and he must send only the number of bytes that the phy
layer
> can
> send.
>
>
>
>
>
> ----- Original Message -----
> From: "lxn" panic at 1... >
> To: ethmac at o...
> Date: Thu, 18 Apr 2002 20:31:05 +0800 (CST)
> Subject: [ethmac] =?gb2312?B?aGVscA==?=
>
> Hi,
> when the tx module sending out frames, if the number of length
> field is smaller than the real frame size, what shall i
do?
> Cut the
> frame to meet the length field or transmit the whole
frame?
> And is
> this considered a error?
> > > ======================================================
> =======
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> ÓÃvipÓÊÃ䣬Ëá¶ÇóÖ°±¦µä¡·£¡ > ¶¨°üÔ¶ÌÃÅ£¬ËÃVIPÓÊÃä £¡ > 10ԪǮÄÜ×öʲô£¿°²È«Îȶ¨£¬¾¡ÔÚÃøÒ×VIPÓÊÃ䣡 > ÃøÒ×VIPÓÊÃ䣬´ò¸öµç»°Ã¢¼´ÓµÓã¡ > > > |
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help
by Unknown on Dec 24, 2008 |
Not available! | ||
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2008/12/24 rahul.achates at gmail.com>
Ethernet is a serial bus protocol where many device can send data, if
I also think that it has something with cable-lengths. If the packet is too
long (literally longer than the cable), it becomes hard to distinguish
signal from reflexes.
Of course, with gigabit ethernet, the packet becomes shorter (in meters) on
the cable, and MTU can be raised (jumbo-frames).
Or, i might be wrong.
--
Kristoffer E. Koch
+47 990 26 250
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maximum data size in one packet is not defined , it may be possible one device will hold the line all time, i think this is the reason , IEEE define maximum size of a packet. |
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