[svn-commits] russell: trunk r62671 - in /trunk/doc: ip-tos.tex qos.tex

Wed May 2 08:17:26 MST 2007

Author: russell
Date: Wed May  2 10:17:26 2007
New Revision: 62671

URL: http://svn.digium.com/view/asterisk?view=rev&rev=62671
Log:
For some reason when I merged 802.1p support, the new documentation file was
not properly added.  Thanks to IgorG for pointing it out!  :)

Added:
    trunk/doc/qos.tex   (with props)
Removed:
    trunk/doc/ip-tos.tex

Added: trunk/doc/qos.tex
URL: http://svn.digium.com/view/asterisk/trunk/doc/qos.tex?view=auto&rev=62671
==============================================================================

--- trunk/doc/qos.tex (added)
+++ trunk/doc/qos.tex Wed May  2 10:17:26 2007
@@ -1,0 +1,119 @@
+\subsubsection{Introduction}
+
+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. 
+
+Also asterisk running on Linux can set 802.1p CoS marks in VLAN packets 
+for all used VoIP protocols. It is useful when you are working in switched 
+enviropment. For maping skb->priority and VLAN CoS mark you need to use 
+command "vconfig set_egress_map [vlan-device] [skb-priority] [vlan-qos]".
+
+\subsubsection{SIP}
+
+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 are four parameters to control 802.1p CoS: "cos\_sip", "cos\_audio", 
+"cos\_video" and "cos\_text". It's behavior the same as writen above.
+
+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.
+
+\subsubsection{IAX2}
+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.
+
+\subsubsection{H.323}
+Also support TOS and CoS. 
+
+\subsubsection{MGCP}
+Also support TOS and CoS.
+
+\subsubsection{IP TOS values}
+
+The allowable values for any of the tos* parameters are:
+CS0, CS1, CS2, CS3, CS4, CS5, CS6, CS7, AF11, AF12, AF13,
+AF21, AF22, AF23, AF31, AF32, AF33, AF41, AF42, AF43 and
+ef (expedited forwarding),
+
+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
+precedence" model as defined in RFC 791 and RFC 1349. They still
+work in this version of Asterisk, but will be removed in future releases.
+
+\subsubsection{802.1p CoS values}
+
+As 802.1p uses 3 bites from VLAN header, there are parameter can take 
+integer values from 0 to 7.
+
+
+\begin{verbatim}
+===========================================
+Configuration	Parameter	Recommended
+File				Setting
+-------------------------------------------
+sip.conf	tos\_sip	cs3
+sip.conf	tos\_audio	ef
+sip.conf	tos\_video	af41
+sip.conf	tos\_text	af41
+sip.conf	cos\_sip	4
+sip.conf	cos\_audio	6
+sip.conf	cos\_video	5
+sip.conf	cos\_text	0
+-------------------------------------------
+iax.conf	tos		ef
+iax.conf	cos		6	
+-------------------------------------------
+iaxprov.conf	tos		ef
+-------------------------------------------
+mgcp.conf	tos		ef
+mgcp.conf	cos		6
+-------------------------------------------
+h323.conf	tos		ef
+h323.conf	cos		6
+===========================================
+\end{verbatim}
+
+\subsubsection{Reference}
+
+IEEE 802.1Q Standard:
+http://standards.ieee.org/getieee802/download/802.1Q-1998.pdf
+Related protocols: IEEE 802.3, 802.2, 802.1D, 802.1Q
+
+RFC 2474 - "Definition of the Differentiated Services Field
+(DS field) in the IPv4 and IPv6 Headers", Nichols, K., et al,
+December 1998.
+
+IANA Assignments, DSCP registry
+Differentiated Services Field Codepoints
+http://www.iana.org/assignments/dscp-registry
+
+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/>.
+
+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>
+

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