sluggish speeds on wifi

Vlad Dracul · #1 July 2nd, 2007, 08:46 AM

good evening all!

i recently hooked up a wireless router to my system. predictably, my download speeds are slower than ever.

i know for certain that if i kept the router off the network, my speeds would be up again.

but with this in mind, is there something i can do to bump my speeds up??

thank you

Archangel122184 · #2 July 2nd, 2007, 02:49 PM

Are you actually using the wireless connection or are you connected by wire and your speeds are still slow?

Vlad Dracul · #3 July 3rd, 2007, 05:37 AM

i'm connected by wire and have slow speeds. could it be the cable being used?

Archangel122184 · #4 July 3rd, 2007, 03:55 PM

Let me be careful here and say "usually" when you have a solid connection with a cable, the cable doesn't effect your speeds. However, I have come across cases where parts of cables were exposed and the twisted pairs unraveled so the EMI/RFI resistance was nullified. It is also possible that the ends of the cable aren't properly crimped which would give you intermittent connection.

I would say that it is more likely that your router has a misconfiguration. More often than not, it is because of the MTU setting in the router that causes slow downs. If you have the MTU set too high your router and the end hosts will have to do a lot of IP segmentation which requires twice the number of transmissions effectively more than doubling your overhead depending on what the actual MTU should be.

Changing the MTU is perfectly safe and you can actually test to find out what your max value is.

start -> run -> "cmd" -> enter

at the cmd prompt use different message sizes with the ping command

ping -l 1450 www.google.com

If you get a response that value is safe. Just increase the value until you no longer get responses. I would start with 1450, most don't go below that.

Once you figure out what your MTU setting should be (or default to 1450 if you like), open your routers main setup page and set it to the new value.

Vlad Dracul · #5 July 8th, 2007, 11:55 PM

that particular setting is on auto and is set to 1500.

what else could be the culprit?

Archangel122184 · #6 July 9th, 2007, 04:14 PM

You obviously didn't try what I asked... Unless you have a dedicated T1 (or better) there is no way your ISP allows an MTU of 1500... nor did you check your cable. If you wish to get help, disregarding advice and asking for more won't get you anywhere.

Vlad Dracul · #7 July 9th, 2007, 10:16 PM

the router's mtu is set to 1500. i had changed it to 1550 since 1600 timed out in the cmd prompt.

also, upon changing it, my connection was no longer established. your advice was not ignored

**z1p** · #8 July 9th, 2007, 11:29 PM

Quote:

Originally Posted by Vlad Dracul

the router's mtu is set to 1500. i had changed it to 1550 since 1600 timed out in the cmd prompt.

also, upon changing it, my connection was no longer established. your advice was not ignored

So "ping -f -l 1500 www.google.com" works from the command line?

Have you tried another cable?

If you are not using the wireless connection, then turn that off at the router.

BTW - what do you have for a router?

Vlad Dracul · #9 July 9th, 2007, 11:44 PM

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\AnuBis>ping -f -l 1500 www.google.com

Pinging www.l.google.com [72.14.253.103] with 1500 bytes of data:

Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.

Ping statistics for 72.14.253.103:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Documents and Settings\AnuBis>

ping -l command line is timing out now with 1500.

linksys a+g wrt55ag

i just might have to take the router off if this persists. i have it mainly for my brother's laptop and my nintendo wii but the speeds are frustrating

**z1p** · #10 July 10th, 2007, 12:13 AM

Keep reducing the value for the "-l" until then set that value as the MTU at the router and at your PC.

Vlad Dracul · #11 July 10th, 2007, 01:26 AM

am i using the "-f -l" command or just "-l"?

what would indicate a good value once i've done so?

**z1p** · #12 July 10th, 2007, 02:10 AM

The -f and -l.

And good value is one that doesn't time out.

Vlad Dracul · #13 July 10th, 2007, 04:39 AM

do i choose the one with the best average ping?

Archangel122184 · #14 July 10th, 2007, 02:37 PM

You should chose the highest value for -l that allows pings to return. What you are doing is testing to see what the largest packet is that your network will support.