[Asterisk-Users] QoS in asterisk

[Rich Adamson]

> Does asterisk provide quality of service(QoS)? If it does, how do I use 
> it? The reason why I ask is that I need to switch to use POTS should the 
> internet connection becomes poor?

Asterisk 'participates' in the qos process by allowing you to set TOS
bits in the IP header. For example:
In sip.conf
 tos=0x18    ;sets ip tos bits lowdelay & throughput
In iax.conf
 tos=lowdelay 

However, its up to your infrastructure equipment (eg, routers & switches)
to prioritize packets received, and send those on to the next hop
following the objectives that you program into those devices. Not all
devices support qos however.

When using Internet connections, you can control qos for packets leaving
your site, however you normally can't control how your ISP (and their
providers) handle it (if at all) for incoming packets. Some ISPs are
actually doing some qos, but most are not.

There is no logic built into asterisk that would support a decision
making process of chosing one path verses another based on past
quality, etc.

Rich