Thanks for the hints.
I found the Quatech MPAP-200/300 RS422/485 PCMCIA card in a magazine ad.
Not a hint of Linux support on their web page but looks like it would
act as a high speed (up to 2.45 Mbit) serial port. Coupled with a good
laptop, this would make a beautiful portable analyzer. I suppose the
Kernel would have to be modified to work with the card's 1024 byte
buffer.
The protocol stack in the SONET bit stream in question is LAPD/CLNP/TP4.
gharris@xxxxxxxxxxxx wrote:
>
> > Let me add that I would be very interested in hearing from anyone who
> > knows about high speed serial support in Linux/Ethereal. We have SONET
> > analyzers that export the overhead data channel to a
> > V.11/V.35/RS422/RS449 - some sort of balanced, synchronous port. This
> > interface is also used in Wide Area Network applications at T1 or E1
> > speed but I have not seen Linux drivers. Perhaps I just don't know
> > where to look. Can anyone on this list point me to information on Linux
> > WAN support?
>
> Well, an AltaVista search for
>
> RS-449 NEAR Linux
>
> turned up
>
> http://www.microgate.com/products/sllinux/sllinux.htm
>
> which says:
>
> The SyncLink WAN adapter for Linux is a high-speed serial
> communications adapter for X86 computers running the Linux
> operating system, version 2.00 and later. The adapter connects
> to remote routers or computers using a variety of wide area
> networking services including DDS, ISDN and T1/E1. SyncLink and
> its device driver are designed to support both single and
> multi-processor operation under Linux.
>
> Designed for use with analog, ISDN, and digital CSU/DSU data
> communications equipment, SyncLink is available in ISA and PCI
> versions for X86 computers. The ISA version supports
> synchronous data rates up to 2.048 Mbps. The PCI version
> supports synchronous data rates up to 10 Mbps.
>
> For flexibility in interfacing with different types of data
> communications equipment, SyncLink features four built-in serial
> data interfaces: V.35, RS-232, RS-422 (RS-530 & RS-449), and
> X.21. Available conversion cables are required for V.35,
> RS-449, and X.21 applications.
>
> The driver looks like a tty driver, and they offer an HDLC line
> discipline for it - I suspect PPP can just plug into it.
>
> Note, though, that Ethereal uses libpcap for captures, and the standard
> libpcap can read traffic only from a network interface; if the overhead
> data channel is only to be treated as a bit stream to be analyzed by
> Ethereal, and isn't passing through the Linux networking code, you'd
> have to modify either Ethereal or libpcap to read the bit stream in
> question.
>
> Note also that Linux's PPP implementation, at least over async lines,
> doesn't provide the PPP headers to "raw" sockets doing network tracing -
> it just provides, I think, IP datagrams and the like. You also don't
> see any LCP traffic.
>
> There are other vendors of WAN cards with Linux support, e.g. Sangoma:
>
> http://www.sangoma.com/
--
Jim Harvey - Tellabs Operations Inc. - SAT
