Cisco 837 - is bandwidth capped somehow?

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Sep 21st, 2007
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I have a Cisco 837 DSL router running in VPN mode to a Cisco concentrator. The line speed is 8mb downstream and 1mb upstream. I am monitoring the the bandwidth and the download bandwidth never goes over 1mb. I just copied a 30mb to 2 PC to this remote site (where the 837 is) and the downstream bandwidth didn't go over 1mb. What is happening?

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Pavel Bykov Fri, 09/21/2007 - 01:10
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This does not have to be because of the router. Can you test the provider speed? With some speed test?

whiteford Fri, 09/21/2007 - 01:16
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Hi, just spoke to our ISP provider and there tests are fine, I was just wondering if the Cisco concentrator or router are limiting bandwidth through out?

Jesusvallina Fri, 09/21/2007 - 09:12
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I have been working with the 800 routers and they DO NOT have a very high thougput when you are doing any type of VPN. We have the 831, 851 and the 871 routers and as you would guess the 851 and 871 are the better ones but you can still kill them with a single VPN tunnel. Do you have dual active tunnels? I would check the CPU when you are doing you down load (sh proc cpu his) this should give you a nice graph on what the cpu load is. I would also make sure no one is using the connection at the same time you are doing the download test. Make sure the cisco concentrator does not bandwidth limiting on.

Good luck.

whiteford Fri, 09/21/2007 - 09:39
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Are those other routers ADSL routers? What is a top end one?

Does the concentrator have bandwidth limiting? If so where?

wochanda Fri, 09/21/2007 - 10:52
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The 8xx series routers are very budget, and thus have low throughputs. Here is a PDF that gives throughputs for all routers:

These numbers are based on no features, 64-byte packets. Depending on features and packet size, these numbers change a lot.

My very rough estimates for these routers with VPN and maybe another feature or 2:

83x: 2mbps

85x: 3mbps

87x: 8mbps

If you need a DSL interface, the 3 corresponding routers are 837, 857, and 877. I'd imagine the only one shipping at this time is the 877.

If you need much more throughput, you'll probably have to look at the 18xx series with a DSL WIC card.


whiteford Sat, 09/22/2007 - 22:51
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Which 18xx series router would it be with a DSL card?

Jesusvallina Fri, 09/21/2007 - 11:53
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Yes they are, I was testing a Cisco 831 router that we use for site to site VPN's and a new 871 that we started to roll out this year. We are using Cisco 3060 VPN concentrators as the tunnel end point.

To check for bandwidth policies follow this.

Configuration | Policy Management | Traffic Management | Bandwidth Policies

Now look on the Bandwidth Policies option screen and look if you have any policies created.

Configuration | Interfaces | Ethernet 1

Look on the bandwidth tab and see if you need see a bnadwidth policy appiled.

Configuration | Interfaces | Ethernet 2

Look on the bandwidth tab and see if you need see a bnadwidth policy appiled.

whiteford Sat, 09/22/2007 - 08:39
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Bandwidth Policies = no policy

Ethernet 1 = Bandwidth management and policy box not ticked, link rate set to 1544kbps

Ethernet 2 = Bandwidth management and policy box not ticked, link rate set to 1544kbps

Jesusvallina Mon, 09/24/2007 - 08:22
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That should be fine. I guess that you do not have a bandwidth policy defined. We have had problems with the 3000 not really giving up the bandwidth that we should be getting. Are you using it for site to site or just enduser tunnels? why model do you have? How many tunnels? what is the current Mbps traffic? I have a bandwidth policy on the 3000 that I work with I just don't limit traffic, I just use it to see how much traffic the site is using (We do site to site tunnels we have 410 tunnels on a 3060 at 90+ cpu load.


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