Page 377 - Asterisk™: The Future of Telephony

qualify
You can set qualify to yes, no, or a time in milliseconds. If you set qualify=yes,
PING messages will be sent periodically to the remote peers to determine whether
they are available and what the latency between replies is. The peers will respond
with PONG messages. A peer will be determined unreachable if no reply is received
within 2,000 ms (to change this default, instead set qualify to the number of mil-
liseconds to wait for the reply).
qualifyfreqok and qualifyfreqnotok
These two settings are used to determine how frequently Asterisk should ping a
peer when qualify is set. The qualifyfreqok setting determines how often to ping
the peer when it’s in an OK state, and qualifyfreqnotok determines how often to
ping the peer when it’s not in an OK state.
qualifysmoothing
You can set qualifysmoothing to yes or no. If enabled, Asterisk will take the average
of the last two qualify times. This helps eliminate having peers marked as LAGGED,
especially on a lossy network.

sendani
The SS7 PSTN network uses Automatic Number Identification (ANI) to identify a
caller, and Caller ID is what is delivered to the user. The Caller ID is generated
from the ANI, so it’s easy to confuse the two. Blocking Caller ID sets a privacy flag
on the ANI, but the backbone network still knows where the call is coming from:

sendani=yes

ANI has been around for a while. Its original purpose was to deliver
the billing number of the originating party on a long-distance call
to the terminating office. Unlike Caller ID, ANI does not require
SS7, as it can be transmitted using DTMF. Also, ANI cannot be
blocked.

transfer
You can set transfer to yes, no, or mediaonly. If set to yes, Asterisk will transfer the
call away from itself if it can, in order to make the packet path shorter between the
two endpoints. (This obviously won’t work if Asterisk needs to transcode or trans-
late between protocols, or if network conditions don’t allow the two endpoints to
talk directly to each other.) If it is set to no, Asterisk will not try to transfer the call
away from itself.
If set to mediaonly, Asterisk will attempt to transfer the media stream so that it goes
directly between the two endpoints, but the call signaling (call setup and teardown
messages) will still go through Asterisk. This is useful because it ensures that call
detail records are still accurate, even though the media is no longer flowing through
the Asterisk box.

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