[werps]

I'm on wan/lan and have an I-19 on the roof, and a router, then a dual snow abs. I get speedtest of 230kbs-256kbs on his sight , local here. I can only get 100- 170kbs with any www sights. My Service provider is sharp and has helped lots but we can't make it better! Any Ideas? We have tried, I think, most common fixes. Thanks , Tom

[ghporter]

Can you be more specific about:

"his sight" (Whose site?)
"I-19" (Just what is an I-19?)
"My Service provider" (Who is it specifically?)
What kind of service (specifically) do you have?

I'm intrigued, but lost.

[werps]

Ok, I am not too sharp but the i-19 (tranzeo?) is a wireless dsl type thing that goes to a tower about 2 miles away (wirelessly) and it goes to a g5 dish on my service providers biulding (starpoint.net) where it ties to the internet. Here, down from the roof (i-19) comes a little tiny box (filter) then to the router( linksby D? wireless with ears pulled and wireless turned off) then to ABS snow dual, then to me wireless computers. Hope that helps a bit. Thanks , Tom

[werps]

I never know what to call my service because I always hear it in so many ways! DSL? Wan? Wan/Lan? Wireless? Dsl wan lan? After describing my set up would it just be called DSL or what? Thanks , Tom

[werps]

Let me try to say this better. Starting from the airport card in my computer the signal goes to my abs (snow dual) that is near and gives a strong signal. I have done positional things for best performance. I have no 2.4 ghz microwaves etc that would give interference. As far as any settings on the powerbook and abs, channels changes, packet sizes, SNMP Access and Remote Configuration on and off, All updates to date.

Next is the router Have swapped that out from a good one just to see if there was a difference, none. Now it is a Linksys wireless G broadband router up to date. I have disabled the wireless by pulling off the ears and turning off wireless so to use it just as a hard wired router. I have tried some changes in the router such as packet sizes,(mut?), manual DNS, we also tried a static ip,

Next is a little box about 2"w x3"d x 1"h we have swapped that out too I guess it is a filter I have been told? I would like to know more about this piece if someone knows more of what it is and what it does ?

Next it goes to the i-19 (dsl transmitter? with a transzeo? card in it.) Swapped this once too. This is a flat white box about 1" thick and about one foot by one foot. It transmits the signal to a tower 2 miles north and then shoots it to a dish 5 miles south right back over me to a dish I think called a 5g on my service providers building and down in and to t lines i suspect. All I know. I have fine tuned the i-19 for best position for signal strength. I have put this i-19 up on a 40 foot tower for better reception. We have made a few changes on this tranzeo card like manual ip's and such as to not pick up other cards in the area or my computers picking it up instead of my abs. Just all I know.

I have hooked up my laptop right to the little box filter thing to bypass all the other stuff and it does better but still 240 -1300kbs , verses 100-200? with abs and router etc. Now My service provider tells me I can not plug into the i-19 without going through this filter or I will burn out my powerbook otherwise I would try that. One more note that I have heard that there is alot of noise from the north tower but they have worked on that. They are monitoring me at the service provider place and the signal that they see is super great! He does agree that there is a problem with my set up and can't figure it out. Others in the area get solid 240-256kbs.

Well I know this is hard to trouble shoot with this info in this manner but all else has failed I would do about anything to get 200kbs steady! Hope someone has the big cure! Hope you forgive the four line rule but how do I explain this in four lines? Thanks , Tom

[werps]

Oh man, NOT 1300kbs, 130kbs Sorry

[ghporter]

I'd say the first thing to look at is your MTU size. In the router you have a setting (probably under Advanced) for this value. The default is 1500, but typical DSL needs something lower because some of the 1500 bytes that value reflects are used by DSL's PPPoE protocol. In a wired DSL environment, moving the MTU down to 1492 (8 bytes for PPPoE) works for most people, but some have to move it down a bit more. Try changing to something like 1468 to see if that helps. If it doesn't, move down by 32 and try again. If you get down to 1404, then it's probably something else, but before changing things back, contact the ISP's tech support and ask what size your MTU should be.

Here's what MTU does. It sets the size of the data payload of every data packet you send. If the packets are too large for your connection, they get "fragmented" - not all of the packet gets sent, so there's some left over, which triggers something called a retransmission. With a slightly too large MTU, you can see an effective throughput decrease of 50%... It's a very important setting.

Your Mac should automatically see that it needs to send smaller packets, but it won't alert you to what size they need to be through the router.

Give that a try and see if it helps.

[werps]

Ok, Can not get info from ISP but if I remember once he said 1200 but I have tried 1200 and 1500 many times but i did what you asked and ran many speed tests and it did not make a much dif. I had changed it this morning as I had it on 1500 but tested it in auto too and it seems the same so I left the router mtu's in auto. All seems about the same maybe the 1404 was a bit better, maybe, but it is so hard to be sure as the speed flux is so much. Thanks I will ck on that sugested mtu from my isp.