On Thu, Jul 30, 2009 at 01:00:46PM +0200, Nordin wrote:
Hi,
according to the wiki for the nanobts:
- 0x00 RSL messages as per GSM 08.58
- 0xfe ip.access specific messages
- 0xff OML messages as per GSM 12.21
I assume this is the so called SAPI?
no. SAPI only exists in E1 based A-bis.
Cause I read some Abis articles that for RSL and OML is resp. 0 and 62. I just want to be sure there are some value differences.
A-bis over E1 is what the BS-11 uses. ip.access has their own proprietary protocol stacking and A-bis dialect. There is no public documentation about it, apart from what we deducted from protocol traces and implemented in OpenBSC / wireshark and put into the OpenBSC wiki.
In any case, the Layer 2 (Q.921 on E1, with TEI and SAPI) is completely uninteresting. All you should care about is layer 3 (12.21 OML and 08.58 RSL).
Whatever is below is the transport layer and does not actually have any actual impact on the GSM netwokr