cancel
Showing results for 
Search instead for 
Did you mean: 

ADSL 500 Maximum Speed

N/A

ADSL 500 Maximum Speed

I'm currently getting between 460-470kbps from my ADSL 500 connection. I realise that this is pretty good but what is the maximum I should get in real-world conditions. Have I reached the limit or is there scope for tweaking?
5 REPLIES
N/A

ADSL Maximum speeds

Hi,
The one thing that alot of people who upgrade to ADSL or go for Broadband afressh (as opposed to a dialup modem) for internet acces forget or just plain dont know about is the fact that ADSL genrally uses the TCP/IP protocol (service) for data transmission and connectivity.

**Transmission Control Protocol / Internet Protocol

TCP/IP is a connection orientated proctcol which means that the data or requested page (webpage or HTML,etc) is guarenteed to arrive intact or free from corruption when displayed on your computer. Inorder for the data to arrive in one piece various rather complex data checking process go on behined the scenes (which most of us either dont know about or take for granted, or just plain dont care about) However the guarenteed connection of TCP/IP incurr's whats termed an OVERHEAD. This overhead can be as much as 25k upto 50K of your ADSL's 512K bandwdth and this alone explains why nobody ever gets the full 512K bandwidth (its a theoretical 512K bandwidth in reality).

So if you are getting 470 to 490 or say 500K on downloads then I believe thats no too bad.

Note: The same overhead issues also apply to uploading as well as downloading. Also applies despite the size of your data pipe even F9's FAT pipes will incurr some level of overheads.

Some speed test sites for ADSL do show the amount of overheads on the live connection. such as DSL Reports site.

Ivan Cool
N/A

ADSL 500 Maximum Speed

Isn't this principle true regardless of whether you happen to be using a connection-oriented protocol (eg TCP) or a connectionless one (eg UDP). If you have a home network, it's probably Ethernet, so it's not IP packets which are running round the place, but Ethernet frames, with the IP packet carried inside the frame as its "payload". And IP itself will be carrying the TCP or UDP data as a payload within its own packet. Similarly, TCP or UDP considers the user's data to be its payload. So at each layer down the network hierarchy (user to TCP or UDP to IP to Ethernet) another "overhead" gets added, each designed to allow that layer of the hierarchy to perform its duties.

Similarly, passing traffic across an ATM network results in the traffic being encapsulated inside ATM cells, with ATM adding its own headers/trailers ("overhead") to allow it to perform its functions. Actually, we use PPPoA (PPP over AAL5, where AAL5 itself stands for ATM Adaptation Layer 5), so doesn't that mean PPP will add it's own "overhead"?
N/A

ADSL 500 Maximum Speed

So...........................is 470bps probably the fastest I'm ever going to see or could I try getting up to 480-490bps?
N/A

ADSL 500 Maximum Speed

I think the simple answer is that no one can tell you whether you would be able to squeeze a bit more out of your connection. There are some people who have reported download figures over 500kbps, so that indicates the technology is capable of delivering higher rates, but whether you will be in a position to realise a higher rate yourself depends on factors such as the quality of your line and the distance from your exchange.

Unless you try, you won't know. If you try, you may find the gains (if any) weren't worth the effort involved. It's your choice. Personally, I can't be bothered.
N/A

Bandwidth & Overheads

Hi,
In reply to Task's comments, Yes! I argee with all that your saying about frames,data packets etc and the layers of the network model etc. and the effect this might have on speeds.

However it is my understanding that one of the differences between TCP,IP & UDP is that UDP being a connectionless orientated protocol therefore doesnt require as much or any of the complex data checking (CRC's) as the other protocols and therefore doesnt incurr any or as much overhead as TCP or IP.
But at the end of the day this is all abit academic really if you ask me, I would only be interested in if I can tweak the system too see if I could squeeze any more performance out of my connection. But the theoretical knowledge is certainly nice to have though.

Ivan