Re: [openss7] Where can I get MTP-2 test packets?

["Brian F. G. Bidulock" <bidulock@openss7.org>]

Matt,

It works like this:

    111111
    54321098 76543210 <- lsbit        ==============>> to line
 +-+--------+--------+--------+--------+--------+--------+--------+-+
 |F|CRC msb |CRC lsb |                  Frame                     |F|
 +-+--------+--------+--------+--------+--------+--------+--------+-+
EOF <------------------      bit stuffed     --------------------> BOF

First bit on wire on the right.

Remember bit stuffing is performed after CRC calculation but before
adding flags.

--Brian

matthias+openss7@corelatus.com wrote:   Sun, 04 Mar 2001 11:42:52
> Hi,
> 
> I'm trying to get an experimental bill-oard which merely sends a
> transparent bitstream from the PCM link to work with the openss7
> stuff, i.e. the unstuffing and CRC work has to be done in software.
> 
> After reading Q.703 a few dozen times, I still don't understand which
> way around the bits in the CRC are meant to be (do they reflect the
> polynomial? do they reflect the input bytes? do they shift right or
> left?) and the easiest way to figure this out would be if I could get
> a few known correct packets, e.g. something like
> 
> FISU with BSN = FSN = 0, BIB, FIB = 0:
> 
>   (flag)     
>  01111110 00000000 00000000 00000000
>  11001100 11000110 01111110  (first bit on the wire on the left)
>   (crc msb...lsb)
> 
> Can anyone point me somewhere I can get some packets?
> 
> Matt

-- 
Brian F. G. Bidulock    ¦ The reasonable man adapts himself to the ¦
bidulock@openss7.org    ¦ world; the unreasonable one persists in  ¦
http://www.openss7.org/ ¦ trying  to adapt the  world  to himself. ¦
                        ¦ Therefore  all  progress  depends on the ¦
                        ¦ unreasonable man. -- George Bernard Shaw ¦