diff options
author | kpfleming <kpfleming@f38db490-d61c-443f-a65b-d21fe96a405b> | 2006-03-28 03:28:52 +0000 |
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committer | kpfleming <kpfleming@f38db490-d61c-443f-a65b-d21fe96a405b> | 2006-03-28 03:28:52 +0000 |
commit | 7c697789d6cce6e95c7297bfcddbc600efe83eed (patch) | |
tree | 2b87d0a9e58db877d4d925a55015ca72d877001d /doc/ip-tos.txt | |
parent | 0d346196f902203b34c480881c27367ae49b522d (diff) |
improve IP TOS support for SIP and IAX2 (issue #6355, code from jcollie plus modifications)
git-svn-id: http://svn.digium.com/svn/asterisk/trunk@15435 f38db490-d61c-443f-a65b-d21fe96a405b
Diffstat (limited to 'doc/ip-tos.txt')
-rw-r--r-- | doc/ip-tos.txt | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/doc/ip-tos.txt b/doc/ip-tos.txt new file mode 100644 index 000000000..bac457e33 --- /dev/null +++ b/doc/ip-tos.txt @@ -0,0 +1,63 @@ +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/>. + |