> 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/
