# [SOLVED] Slow internet with switch connected to router



## turkamure

I have a old linksys wired router connected to road runner service. Then I have a brand new Linksys 16 port switch. The pc's in my network are connected to the switch. When connected to the switch the internet is very slow. 

I first connected my labtop directly to the cable modem. Ran a test through http://www.speakeasy.net/speedtest. Test came back fine 6880kbps down and around 500kbps up. So the isp connection is fine. I then connected the modem to the router in the Wan port. then the labtop to a normal port. Again the test runs fine, same results as above. 

Then I connect the 16 port switch to the router and the labtop to the switch. I have tried two different ways with same results, first through the uplink port on the router, then second just a normal port to the switch. Both ways results in very slow internet speeds. Test results vary, averaging aroung 3300kbps, the upload is always ok. 

My first thought was the cables themselfs. I ever found some info that says the minimum cable length is 2.5m or around 8 ft. So I made new cables and for good measure made them 10ft. This did not help. 

I then tried an old 8port 10/100 switch I had that seems to work ok. The test are better, but erratic and still no where near 6880kbps. 

Sorry for the long post but I'm stumped. As far as setting the devices to auto or full duplex, I am not fimiliar with how to do this on a router or switch, the labtop is set to auto. My thought we be to replace the old router.......


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## johnwill

*Re: Slow internet with switch connected to router*

WOW, I'm stumped too! I've connected a variety of switches of all flavors to routers, and I've never run across an issue like this!


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## joeyoung25

*Re: Slow internet with switch connected to router*

I have a Cisco 3745 Router connected to 3 or 4 cisco catalyst 3550 switches and we have 20mbps internet and only get about 1 mbps. So I am in a similar boat to yours but on a larger scale. We get close to 20mbps when we connect directly to the router but when we go through a switch it gets a lot slower. 

If your connecting a switch to a "linksys" then you're actually connecting a switch to a switch to a router. (All linksys routers have switches built into them.) your making one more step than what you need. Try looking for a Netgear Prosafe Firewall and connect your switch to that. you should see a speed difference because your linksys isnt rated for that much use. My cisco is rated for 1000s of connections at a time.


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## turkamure

*Re: Slow internet with switch connected to router*

It was the router, bought a new linksys router and now it works fine with the switch. No idea why the old one would not, everything else worked fine. Might be something to pay attention to when mixing new hardware with old.


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## johnwill

*Re: Slow internet with switch connected to router*

Glad it was something that you could track down. :smile:


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## jdavies

I've run many new and old pieces of equipment. Typically, the problem with Cisco would be the duplex setting. For some reason; when connecting a Cisco switch to a Cable modem (or any switch for that matter) the auto-negotiation tends to go towards "half-duplex" and this causes upload speed problems; and usually reduces the bandwidth down stream by a value of 1/2


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## elhuevon

jdavies said:


> I've run many new and old pieces of equipment. Typically, the problem with Cisco would be the duplex setting. For some reason; when connecting a Cisco switch to a Cable modem (or any switch for that matter) the auto-negotiation tends to go towards "half-duplex" and this causes upload speed problems; and usually reduces the bandwidth down stream by a value of 1/2


How do check that or change that on a cisco 2900 switch?


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## jdavies

on a Cisco 2900 series, you would log into it (telnet, ssh, or console cable). Then, log into exec mode. (most generic setups will just console you right into the > prompt) from there you type "enable" enter your password and you should see a # prompt. you can issue the command "show interface fast 0/1" (for example, would show the interface 1 statistics.. or you can see the configuration by typing "show run" and this will display the configuration of the router.


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