Linux WAN / synchronous serial cards?

slackwhere · 08-06-2022, 06:42 PM

We have a number of remote sites that are connected to the inet either via T1 or VSAT modems. These links are connected to Cisco routers using sync serial interfaces. HDLC framing and V.35.
We'd like to replace the routers with Linux boxes but are having trouble finding interfaces that will allow us to run IP over the sync serial interface.

If anyone is doing this I'd love to hear what cards/hardware you are using.

business_kid · 08-07-2022, 08:31 AM

What speeds are we talking? There was an early standard for synchronous serial, but it only did 128kbps or the like.

From here, parts are cheap, labour is expensive. Why not replace the modems and do things the normal way?

slackwhere · 08-07-2022, 08:52 AM

Synchronous serial has been around for quite some time and is commonly used for connected routing equipment to telco csu/dsu systems. It, of course, can handle speeds far greater than 128k. Many of these connections are T1 which are 1.5Mbps.

Some of our VSAT rates are 3-5Mbps.

What do you consider the "normal way" for remote sites connected via VSAT modem where there's no other reliable form of connectivity? There's no cell coverage either, all we have is power in some cases.

yvesjv · 08-07-2022, 03:08 PM

Wow, now that is an interesting project.
Haven't had to configure any HDLC/ppp/etc on WIC modules since getting rid of the old 2600XM series routers.
Was going to recommend contacting the likes of Sangoma or Emtech for a solution but no idea what sort of interface you will need.

Considered (if available) Starlink Business at your sites?
https://www.starlink.com/business