Revision as of 09:13, 6 October 2022

Why not TDMoIP / CESoIP?

Usual E1/T1 over IP protocols use generic frames over IP transfer that makes 2 megabits constant rate with up to 8000 packets per second. That approach:

• not suitable for distributed sites with limited internet access
• makes constant parasite load on the servers
• requires delays to compensate jitters
• has issues with asynchronous-to-synchronous transition

Fur such kind of integrations we prefer to have our own agent software on-site with hardware E1/T1 interfaces.

• good timings driven by E1/T1 clock or GPS
• good framing due to synchronous composition on the site
• less traffic due to transfer only valuable demultiplexed information

icE1usb

We have chosen Osmocom icE1usb as a primary interface for our projects for several reasons:

• good compatibility with big range of hardware hosts due to use USB
• in opposite to most of DAHDI interfaces it is in production
• open-source hardware design
• open-source user-space driver, no need for the kernel driver
• suitable API for our purposes
• available at Sysmocom's web shop

[User manual]

Driver installation

We maintained Osmocom E1D in our Debian repository. It has no modifications so you can shose any source of packages you want or build from the sources.

sudo apt install osmo-e1d

Driver configuration

/etc/osmocom/osmo-e1d.cfg

log syslog
 logging filter all 1
 logging level e1d info
e1d
 interface 0 icE1usb
  usb-serial [interface serial number]

More information about logging section can be found here.