[Asterisk-Users] ISPs with QoS for VoIP?

[Roderick Montgomery]

According to alex at pilosoft.com:
> The only case where QoS is useful is on tail-end circuits. Everywhere 
> else, having bigger pipes is much more preferable to QoS.

Um, not to state the obvious, but aren't bigger pipes ALWAYS preferable?

QoS does not make packets move faster.

Please reread the previous sentence.

QoS implementations essentially tell network elements (routers, switches,
etc.) which packets may be slowed or dropped entirely relative to other
packets. I think everyone here can agree that slow or failed delivery of
packets is a Bad Thing. However, since the "bigger pipes" solution usually
carries a monetary cost, it's not always available. 

QoS is a "damage control" technology. If your network needs outstrip your
network capacity, QoS is one way to deal with the problem: attempt to
de-prioritize some traffic to allow more capacity for your voice traffic.

If a network segment or element becomes congested, there are many other
options available -- remove the competing traffic altogether. Complain to or
change your ISP (if it's their problem). Segment your voice traffic with
VLANs.

If your network is already congested, QoS is a way to direct the effects of
congestion at the traffic that is less important to you. It is not a way to
make "good" traffic go faster.

rm
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 Roderick Montgomery   rod at thecomplex.com   <URL:http://thecomplex.com/>
the fool stands only to fall, but the wise trip on grace... [Sarah Masen]
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