Mailslot packets

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2 total messages Started by Tumurbaatar S. Thu, 02 Nov 2006 04:55

#2908

Author: Tumurbaatar S.
Date: Thu, 02 Nov 2006 04:55

17 lines
1710 bytes

My app uses Win32 API Mailslots to broadcast packets between 4-5 pc's
connected to 10Mb HUB.
With this old HUB there was no problem on delivering packets to destination
pc. Because mailslot
datagrams are not reliable,  my app writes 3 packets to mailslot with 100
msec interval. And at least
one of these 3 packets was able to reach to the destination.
Now I changed the old HUB with new Giga SWITCH (and all connected pc's).
And it seems that sometime no one of these packets reaches the dest.
I increased the number of packets to send from 3 to 30 and set the time
interval to 20msec.
And still all 30 packets disappear in about 5% of broadcasting.
Maybe I will move to my old HUB soon, but any ideas?
P.S. The old pc's had Win98 installed. The new pc's are XP and, plus, one
Win2003 server where
above packet lost occurs. The broadcasting are two-ways, i.e. every pc sends
and receives datagrams.

Re: Mailslot packets

#2909

Author: Peter Str�mberg
Date: Thu, 02 Nov 2006 10:53

22 lines
1763 bytes

"Tumurbaatar S." <spam_tumur@magicnet.mn> wrote in
news:45497a1a@newsgroups.borland.com: 

> My app uses Win32 API Mailslots to broadcast packets between 4-5 pc's
> connected to 10Mb HUB.
> With this old HUB there was no problem on delivering packets to
> destination pc. Because mailslot
> datagrams are not reliable,  my app writes 3 packets to mailslot with
> 100 msec interval. And at least
> one of these 3 packets was able to reach to the destination.
> Now I changed the old HUB with new Giga SWITCH (and all connected
> pc's).

Hubs are dumb, they don't know what is attached where, so when a packet 
comes in it is always sent out to all ports.

Switches are smart, they "know" what addresses are on which port, so if a 
packet comes in that doesn't match any destination it will be dropped by 
the switch, unless it is explicitly to an broadcast address.

Also, mailslot packets only uses UDP/broadcasts if the message is less 
than 425 bytes.

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