Page 368 - Asterisk™: The Future of Telephony

that is configured in the [general] section. If this parameter is not configured, the
value defaults to host.
Valid options include:
caller
The inbound caller has priority over the host.
host
The host has priority over the inbound caller.
disabled
Codec preferences are not considered; this is the default behavior before the
implementation of codec preferences.
reqonly
Codec preferences are ignored, and the call is accepted only if the requested
codec is available:
codecpriority=caller|host|disabled|reqonly
delayreject (global)
If an incorrect password is received on an IAX channel, this will delay the sending
of the REGREQ or AUTHREP reject messages, which will help to secure against brute-
force password attacks. The delay time is 1,000 ms:
delayreject=yes|no
forcejitterbuffer (channel)
Since Asterisk attempts to bridge channels (endpoints) directly together, the end-
points are normally allowed to perform jitter buffering themselves. However, if the
endpoints have a poor jitter buffer implementation, you may wish to force Asterisk
to perform jitter buffering no matter what. You can force jitter buffering to be
performed with forcejitterbuffer=yes:
forcejitterbuffer=yes
iaxthreads and iaxmaxthreads (global)
The iaxthreads setting specifies the number of IAX helper threads that are created
on startup to handle IAX communications.
The iaxmaxthreads setting specifies the maximum number of additional IAX helper
threads that may be spawned to handle higher IAX traffic levels:

iaxthreads=10
iaxmaxthreads=100
jitterbuffer (channel)
Jitter refers to the varying latency between packets. When packets are sent from
an end device, they are sent at a constant rate with very little latency variation.
However, as the packets traverse the Internet, the latency between the packets may
become varied; thus, they may arrive at the destination at different times, and
possibly even out of order.

340 | Appendix A: VoIP Channels