Revision as of 09:00, 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 repositories. 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 stderr
 logging filter all 1
 logging color 1
 logging print category-hex 0
 logging print category 1
 logging print thread-id 0
 logging timestamp 1
 logging print file 1
 logging level e1d info
e1d
 interface 0 icE1usb
  usb-serial [interface serial number]
  line 0
    mode superchannel