asterisk users - Oct 2004 - Bandwidth control on a home office network

Hi,

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]

Thanks for any tips.

BR /adam.

Adam Holt wrote:
> Hi,
> 
> 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]
> 
> Thanks for any tips.
> 
> BR /adam.
> 
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	The Cisco 7960 does QoS by setting TOS bits.  Furthermore, it works 
best when used with other Cisco switches (especially ones with the new 
AutoQoS feature). You need something that can understand those, back to 
your original router problem.

	If you are in the US, you can pickup a Linksys WRT54GS for well under 
$100 that you can do an amazing amount of things on.  You can now even 
do QoS with the Linksys firmware, although alternative firmware 
(Sveasoft, OpenWRT, etc.) is more fun.

	A cisco router would work, but I don't think that you need to blow that 
much money for a home router, especially when the Linksys WRT's are so 
much fun!

	I actually don't know if any of the LinkSys firmware understands ToS, 
but you can do Qos and bandwidth shaping using other means.  Check it out.

--
Kristian Kielhofner

> 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.

On Sat, 16 Oct 2004, Rich Adamson wrote:
> 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.
Well - you can use your handy Linux box for some rough and ready control 
of inbound traffic.

I just do the following to limit TCP traffic to 200k; that leaves 300 or 
so for UDP

# Adjusted by SLD for tcp only.  Brute force way to not disturb VOIP
tc filter add dev $DEV parent ffff: protocol ip prio 50 u32 \
   match ip src 0.0.0.0/0 \
   match ip protocol 0x6 0xff \
   police rate 200kbit burst 10k drop flowid :1

The tc rule just causes packets to be dropped if the rate gets too high.  
TCP sees that as congestion and slows up.

Steve

----- Original Message ----- 
From: "Adam Holt" <adamholt@mac.com>
To: <asterisk-users@lists.digium.com>


> Hi,
>
> 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]
>
> Thanks for any tips.
>
> BR /adam.


I use IPCOP - it's another open source project.  It does traffic 
shaping, routing, firewalling, DMZ, etc.  It's free and runs on an old 
PC (I use Pentium 200MHZ w/128MB RAM - but I need it that fast because 
it's also a content filter for my home network/kids.

www.ipcop.org

Did I mention, it's free?

Roger