[Asterisk-Users] Bandwidth control on a home office network

[Rich Adamson]

> I have a Grandstream ATA today connected to my 750k broadband 
> connection via an older router / firewall that doesn't have any QoS / 
> ToS capability.  It works fine apart from the obvious problem of when 
> large emails come in or somebody else on the network starts d/l-ing 
> something big off the web.
> 
> I'm wondering whether to swap the router for a Cisco in order to 
> introduce some local bandwidth control.
> 
> Alternatively I was wondering if I picked up a Cisco 7960 handset 
> instead - is the 2nd ethernet port routed through the device, or does 
> it just act as an Ethernet repeater, i.e. if I arranged the handset in 
> the network as below would I get bandwidth prioritisation for the 7960?
> 
> [CABLE MODEM]------[7960]-------[FW / ROUTER / HUB]--------[REST OF MY 
> NETWORK]

QoS, regardless of whether its based on the IP header TOS bits or on
specific tcp/udp port numbers, essentially prioritizes the "outbound"
flow of data packets, sending high priority packets before lower
priority packets. It does nothing for inbound data such as downloads
to your site.

Most broadband connections have a different upload vs download speed,
where usually the download speed is substantially greater then the
upload speed. E.g., not uncommon to see DSL or Cable modems limited
to 758k down and 128k/256k upload speeds. QoS may help with prioritizing
traffic through the 128k/256k. However, your internet service provider
would need to prioritize the download traffic for you.

There are some rather expensive devices that you can install that will
rate limit both upload and download traffic. Those devices artifically
control the download traffic by withholding TCP acknowledgment packets,
etc. Not sure how effective they are though.