Re: How to know the packet loss ratio of SCO socket

Marcel Holtmann <[email protected]> Fri, 15 Aug 2008 19:26:39 +0200
Newsgroups gmane.linux.bluez.devel
Message-ID <[email protected]>
Hi Jui-Hao,

> as the title said, I am writing a simple server-client socket  
> program for SCO
> connection. While client is sending the SCO packet to server, it  
> attaches a
> sequence number to it. Then I want server to estimate the packet loss.
> [Client program is as the following]
> for (i = 0; i < 48, i++) buf[i] = 0x7f;
> while (1) {
>  *(uint32_t *)buf = htobl(seq);
>  *(uint32_t *)(buf+4) = htobs(48);
>  if (send(sockfd, buf, 48, 0) < 0) break;
>  seq++;
>  usleep(1)
> }
>
> However, on the server side, the data is total different, and I am  
> not able to
> get the sequence number (the hcidump -x also shows different data  
> content as I
> expect. Also, it's weird that the content is repeated)
>
> Is this data encoded? or is there anyway to know the packet loss  
> ratio of the
> SCO connection?

SCO are voice connections and they are CVSD encoded. It is not a  
reliable data transport. Use L2CAP or RFCOMM for that.

Regards

Marcel



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