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Cisco 1841 Bottleneck

Posted on 2009-04-03
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Last Modified: 2012-05-06
Hi All

We recently upgraded to a 50Mbit internet connection. A basic topology is this.

50Mbit FibreLLink --> Cisco 1841 --> Cisco ASA 5510 ---> Network Switch

If I plug a laptop (with IP of Cisco 1841)  into the fibre link and run a speedtest (I am based in the UK) so I use the following.
http://www.speedtest.bbmax.co.uk/, http://www.1024.co.uk/speedtest/speedtest4.php

I get over 50Mbit (up & down) on both tests.

If I plug a laptop with the IP of the firewall I get around 5-10Mbit down and about 2 - 10Mbit upload.

I get the same when run from a PC on the network, so I believe the bottleneck is on the 1841.We used to have a 5 Mbit conenction so we wouldn't notice.

Below is the Interface config, I am stumped, obviously ISP won't help as the speed if fine on the demarkation point.

Any ideas.

Thanks

Arm
interface FastEthernet0/0

 description Armxxxx-Primary-POP

 ip address 217.xxx.xxx.42 255.255.255.252

 speed 100

 full-duplex

!

interface FastEthernet0/1

 description Armstrong-Local-LAN

 ip address 217.xxx.xxx.1 255.255.255.240

 duplex auto

 speed 100

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Question by:ArmstrongInt
8 Comments
 
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Expert Comment

by:RPPreacher
ID: 24058729
Have you tested speeds without the ASA?  Just router to laptop?
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Author Comment

by:ArmstrongInt
ID: 24058788
hi

I have tested laptop --> 1841 --> Fibre Link where the laptop has IP of ASA, this is whats leads me to believe the bottleneck is indeed the 1841.

Thanks

Arm
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Accepted Solution

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RPPreacher earned 500 total points
ID: 24058929
This is usually a speed/duplex issue on the router.  Change Fa0/1 to either static 100/full or auto/auto.  Static speed (100) and auto duplex is bad.
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Expert Comment

by:egyptco
ID: 24059048
I'm suspicious about how all these speed tests are trustworthy but you can still try to troubleshoot your router:

1. configure speed and duplex settings of the outside interface of auto and run your tests again.
2. configure speed and duplex settings of the inside interface of auto and run your tests again.
3. check the cpu and memory utilization.
4. check if there are enough free blocks (sh blocks). if the  LOW column of especially 1550ed blocks closes zero you have experienced for sure at least once congestion.
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LVL 1

Author Comment

by:ArmstrongInt
ID: 24059069
Hi RPPreacher.

So now my conf looks like

interface FastEthernet0/0
 description Armxxxx-Primary-POP
 ip address 217.xxx.xxx.42 255.255.255.252
 speed 100
 full-duplex
!
interface FastEthernet0/1
 description Armstrong-Local-LAN
 ip address 217.xxx.xxx.1 255.255.255.240
 full-duplex
 speed 100

That has made the downloads now about 50Mbit from the LAN clients, but for the some reason the uploads are jammed about 2-3Mbit, were as before it would go as high as 20Mbit from the LAN.

My ASA interfaces have no duplex or speed settings, maybe I need to implement on it too ?

Thanks again

Arm
0
 
LVL 20

Expert Comment

by:RPPreacher
ID: 24059241
Yes.  Everything needs to match on speed and duplex.
0
 
LVL 1

Author Comment

by:ArmstrongInt
ID: 24059627
Hi

Finally it works. RPPreacher as you suggsted. I had to change all the interfaces to auto/auto.

Getting 91Mbit down and 50Mbit up.

Thanks again

Cheers

Arm
0
 
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Expert Comment

by:theoaks
ID: 24059891
so jealous of that bandiwth

australia is c**p for internet speed!
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Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

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