mirror of
https://github.com/asterisk/asterisk.git
synced 2025-09-06 04:30:28 +00:00
64 lines
2.8 KiB
Plaintext
64 lines
2.8 KiB
Plaintext
|
IP Type of Service settings for VoIP channels
|
||
|
|
---------------------------------------------
|
||
|
|
|
||
|
|
Asterisk can set the Type of Service (TOS) byte on outgoing IP packets
|
||
|
|
for various protocols. The TOS byte is used by the network to provide
|
||
|
|
some level of Quality of Service (QoS) even if the network is
|
||
|
|
congested with other traffic. For more information on Quality of
|
||
|
|
Service for VoIP networks see the "Enterprise QoS Solution Reference
|
||
|
|
Network Design Guide" version 3.3 from Cisco at:
|
||
|
|
|
||
|
|
<http://www.cisco.com/application/pdf/en/us/guest/netsol/ns432/c649/ccmigration_09186a008049b062.pdf>
|
||
|
|
|
||
|
|
In sip.conf, there are three parameters that control the TOS settings:
|
||
|
|
tos_sip, tos_audio, and tos_video. tos_sip controls what TOS SIP call
|
||
|
|
signalling packets are set to. tos_audio controls what TOS RTP audio
|
||
|
|
packets are set to. tos_video controls what TOS RTP video packets are
|
||
|
|
set to. There is a "tos" parameter that is supported for backwards
|
||
|
|
compatibility. The tos parameter should be avoided in sip.conf
|
||
|
|
because it sets all three tos settings in sip.conf to the same value.
|
||
|
|
|
||
|
|
In iax.conf, there is a tos parameter that sets the global default TOS
|
||
|
|
for IAX packets generated by chan_iax2. Since IAX connections combine
|
||
|
|
signalling, audio, and video into one UDP stream, it is not possible
|
||
|
|
to set the TOS separately for the different types of traffic.
|
||
|
|
|
||
|
|
In iaxprov.conf, there is a tos parameter that tells the IAXy what TOS
|
||
|
|
to set on packets it generates. As with the parameter in iax.conf,
|
||
|
|
IAX packets generated by an IAXy cannot have different TOS settings
|
||
|
|
based upon the type of packet. However different IAXy devices can
|
||
|
|
have different TOS settings.
|
||
|
|
|
||
|
|
The allowable values for any of the tos* parameters are:
|
||
|
|
|
||
|
|
be (best effort), cs1, af11, af12, af13, cs2, af21, af22, af23, cs3,
|
||
|
|
af31, af32, af33, cs4, af41, af42, af42, ef (expedited forwarding),
|
||
|
|
lowdelay, throughput, reliability, mincost, none
|
||
|
|
|
||
|
|
The tos* parameters also take numeric values.
|
||
|
|
|
||
|
|
The lowdelay, throughput, reliability, mincost, and none values are
|
||
|
|
deprecated because they set the IP TOS using the outdated "IP
|
||
|
|
prececence" model as defined in RFC 791 and RFC 1349.
|
||
|
|
|
||
|
|
===========================================
|
||
|
|
Configuation Parameter Recommended
|
||
|
|
File Setting
|
||
|
|
-------------------------------------------
|
||
|
|
sip.conf tos_sip cs3
|
||
|
|
sip.conf tos_audio ef
|
||
|
|
sip.conf tos_video af41
|
||
|
|
-------------------------------------------
|
||
|
|
iax.conf tos ef
|
||
|
|
-------------------------------------------
|
||
|
|
iaxprov.conf tos ef
|
||
|
|
===========================================
|
||
|
|
|
||
|
|
To get the most out of setting the TOS on packets generated by
|
||
|
|
Asterisk, you will need to ensure that your network handles packets
|
||
|
|
with a TOS properly. For Cisco devices, see the previously mentioned
|
||
|
|
"Enterprise QoS Solution Reference Network Design Guide". For Linux
|
||
|
|
systems see the "Linux Advanced Routing & Traffic Control HOWTO" at
|
||
|
|
<http://www.lartc.org/>.
|
||
|
|
|