ACNS configuration

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Jul 24th, 2008
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I have wae612 with last version of ACNS on it.

I run it like a transparent proxy using wccp v2 together with cisco7206.

If I test caching with only my PC - WAE612 performs great.

Problem - when I divert all customers' traffic to WAE - it begins to download a lot of data from Internet giving only a part to customers. So traffic is increasing with WAE612 deployed.

Sniffer shows only WAE's IP and only TCP 80 port - seems like everything is clear. But uplink is completely loaded.

Content preloading is switched off.

If somebody can share a config of router and ACNS - I will appreciate. Only simple web-cache is needed.

If any idea - also welcome.


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dstolt Fri, 07/25/2008 - 04:07
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That's interesting, it increases the traffic? If you have caching turned on, traffic shouldn't increase unless there is something else going on.

Do you have a CFS disk partition? You need to configure CFS for HTTP caching to work. Verify by using the "sh disk current" command in the CLI.

Run the following on the cli to see more of what is going on:

"sh stat http savings" to see if you are saving bw.

"sh stat http requests" to see what kind of requests you are getting.

"sh stat http miss-reason" to see why you are getting cache misses.

There are a ton of HTTP configs that you can play with once you see why you are getting cache misses.

I might also turn on transaction logs for a while to see if there is something strange about client activity (all cache misses) or something. This allows you to see all the request and how each http GET request is handled (to compare your sniffer traces).


hetene_kaz Fri, 07/25/2008 - 16:28
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Thanks for reply.

It seems like I just found the problem.

When I divert GPRS users to WAE612 - traffic is increasing amazingly due to the speed. Usually GPRS user has speed not more then 80kbit/s and RTT to GW not less then 500ms (so TCP window is small) but CE that downloads data on behalf of the GPRS user has much more bandwidth then GPRS terminal. So if even 20 active GPRS users will go thru CE - they will kill my upstream. So the CE downloads data to cache very fast but then passes the downloaded data very slowly.

How can I tell the CE not to download more data unless it is transmitted to a requested user?

With LAN users I do have no problem.

I see in CE configuration TCP buffers set - can I modify them to solve the problem?

dstolt Sun, 07/27/2008 - 17:16
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Are you trying to increase the download speed to the GPRS clients or the upsteam servers? I'm not sure that is what you want to do. We can set a bandwidth for a protocol or subnet, would that help? Or you might bypass the GPRS clients altogether since they are inherently slow with such small buffers.


hetene_kaz Sun, 07/27/2008 - 18:30
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I am trying to save internet channel bandwidth.

Now GPRS customers use around 50% of that channel - so bypass is not good idea. CE was purchased mostly for this type of traffic.

Bandwidth for subnet also will not help - many users will be shaped to a limited badwidth.

If only I could make CE not to download data unless it passed to GPRS user... In other words, to make some transparent TCP-window from internet to GPRS user thru CE or soething like that.

dstolt Mon, 07/28/2008 - 19:52
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Sorry, I'm trying to understand what kind of traffic they are requesting and why it's so much worse then other users. Are the GPRS customers making many more HTTP GET requests then they are receiving? ACNS should only be forwarding requests that it receives from clients.

Are you getting any cache hits on that traffic? Or is it being re-requested every time. Maybe we can force IMS instead of object refresh or cache-no-cache rules.


hetene_kaz Mon, 07/28/2008 - 20:00
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They are requesting the same http(tcp 80).

I get hit increasing.

Problem is - when GPRS user submits some request - CE downloads it very fast (using high bandwidth) and then passes the downloaded page to GPRS user slowly.

So if 10 users submit 20 requests - CE will create 20 outside TCP sessions and download pages using almost all available internet bandwidth. And then, withing 5-10 minutes will pass the pages slowly to GPRS users.

If I divert LAN users - i have no problem because speeds are equal (user->internet=user->CE->internet).

Have you got my point?

What is IMS??

dstolt Mon, 07/28/2008 - 23:02
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If-Modified-Since: A way for checking for content freshness without re-requesting the content...

Unfortunitely there is no way to limit the upstream bandwidth unless you limit all the clients or use an advanced config file for HTTP (see:

That might help to do what you are doing.



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