Documentation on writing a custom socket

Hans Petter Selasky hselasky at
Sun Mar 9 09:26:37 UTC 2008

On Saturday 08 March 2008, Robert Watson wrote:
> On Sat, 8 Mar 2008, Hans Petter Selasky wrote:

> For example, do you
> anticipate using or even needing the routing facilities, and how might you
> map ISDN telephony parts into the normal network stack infrastructure of
> addresses, routing, interfaces, etc?

Hi Robert,

ISDN is very simple. In the ISDN world there is a term called TEI which is the 
Terminal Entity Identifier. This kind of like an IP address.

Besides from the signalling there are 2 B-channels which can transport data or 
audio. One of my goals is to achive zero copy when moving data to/from an 
ISDN line and also in combination to Voice over IP. Currently data is moved 
through userland (Asterisk typically) which is usable in the short term, but 
in the long run I want this extra copying removed. The idea is that I can 
route [IP] packets (mbufs) through various filters in the kernel without the 
need for copy.


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