Quality of Service Blog

Recently I’ve installed the newest  Asterisk 1.6.2.6.  I dealt  with Asterisk few times in past but never focused on QoS capability. What I found interesting is that in sip.conf there are fields for setting ToS field (with default values provided):

• tos_sip=cs3   (SIP signalling messages)
• tos_audio=ef    (RTP audio)
• tos_video=af41    (RTP video)
• tos_text=af41    (RTP text)

Settings are also avaliable for other protocols:

Even those parameters are named ToS they actually set DSCP. It might be misleading, because ToS it is full byte, whilst DSCP is a 6-bits part of ToS field.