Extension Information is part of the GPRS Cell Options IE, as
specified in Chapter 12.24 of TS 04.60. It is needed for
indicating EDGE capabilities of the BTS to the MS.
This simply adds the code to encode this IE as part of SI13,
but does not actually use the code yet.
Before this commit, OpenBSC used templates for the SYSTEM INFO
1, 2, 3, 4, 5 and 6 messages. Those templates were patched in
various places to reflect the network config like ARFCN.
Now, we actually generate those SI messages ourselves, using
values from the configuration file, and even calculating neighbor
cell lists.
All bts'es that you have configured in OpenBSC will end up in
the neighbor cell list - which should be more than sufficient for
the current small-single-site networks.
Harald Welte