Feature #6417
openCRC4 configuration
90%
Description
Even if the icE1usb support CRC4 enabled or disabled the osmo-e1d process need CRC4 on Rx to align.
I suggest that we do CRC4 check configurable.
On a Cisco modem pool you can disable CRC4 in the E1 controller section:
controller E1 2/1 framing NO-CRC4 pri-group timeslots 1-31 description Towards Kanin-Q921_4
Maybe we can do the same in the line section in the config file, something like this:
e1d interface 0 icE1usb usb-serial xxxxxxxxxxxx line 0 framing no-crc4 mode e1oip
// Peter
Updated by tnt about 1 month ago
- Category changed from firmware to gateware
The gateware currently has no such support CRC4 is always used for multi frame alignement, so it needs to be added there first.
Updated by tnt 41 minutes ago
- % Done changed from 0 to 90
Should be mostly implemented:
- The gateware is pending hardware testing (I tested it interoperates with itself but I don't have any other non-CRC HW up atm)
- No firmware changes required
- osmo-e1d PR to add config options is in gerrit ( https://gerrit.osmocom.org/c/osmo-e1d/+/36653 )
- dahdi PR to properly configure the RX side is in gerrit ( https://gerrit.osmocom.org/c/dahdi-linux/+/36655/1 )
The TX mode and RX mode are independent.
On the TX side if you don't select one of the CRC4 mode, then the Si bit are also not set to the CRC4 multi-frame pattern (they are just taken from what the host provides like the Sa bits, which are set to '1' by default in osmo-e1d).
On the RX side you can select either FRAME (non-CRC4) or MULTIFRAME (CRC4) alignement mode. In the former, the core just check the alternating FAS/non-FAS pattern and stops there. In the latter, once the FAS/non-FAS pattern is locked, it will start checking Si bits and the CRC4 bits to confirm multi-frame alignement.
To my understanding, this is what the specs says we should do for non-CRC4 / CRC4 modes.
