Megabitz maintains sufficient server capacity to provide customers with the ability to fill broadband Internet connections. However, capacity is only one of a number of variables that can impact the speeds that you receive from the Megabitz Usenet service.
NNTP, the protocol used to exchange Usenet news, is layered on top of TCP, an Internet standard for communications. TCP is a protocol that was designed to work even in severely suboptimal situations. However, some of the mechanisms that allow it to work in suboptimal situations can reduce the actual speeds you receive.
Any amount of packet loss in the network will act to slow down a TCP connection.
As the packet round trip time increases, so does the bandwidth x delay product of the connection. An optimal TCP connection requires that the operating systems on each end be able to buffer at least as much data as can be handled in-flight. What this means is that while users that are close to the Megabitz servers probably don't have to worry, users who are far away may gain benefits from some changes to their operating system settings.
To determine whether or not there may be a packet loss problem between your PC and the Megabitz servers, you may run a ping test.
To get a reasonable sample, we suggest that you ping news.megabitz.net with 100 packets that are 1500 bytes.
Ping For Windows XP Users
Open your Start menu, select "Run...", and enter "cmd". This will open a command window. In this window, run "ping -l 1500 -n 100 news.megabitz.net"
PLEASE NOTE: Interpreting ping results is complex. For example, anti-DoS technologies may limit the number of replies, even when there is no actual packet loss. If you see packet loss indicated, please contact us to allow one of our network engineers to investigate. Include a cut and paste of the ping command output if possible.
To ensure the greatest possible speeds for your downloads, the Megabitz servers are configured to support huge TCP transmit buffers. Unfortunately, most operating systems, including Windows, do not automatically support this, and will instead use a much smaller size.
Fortunately, this client-side problem is easily corrected. Correcting this will most likely accelerate your Megabitz sessions, and also most other Internet activities as well!
The SG TCP Optimizer, by Speed Guide, Inc. is our preferred tool for tweaking Windows for optimum performance. This tool may be downloaded here. After running this, you will need to reboot your PC.
Quick Tune-Up
If you just want a quick tune-up, select the network adapter your Internet connection is on, then select the connection speed, click on Optimal settings at the bottom, and then select Apply changes. That's it. For most users, this will be as good as the detailed tune-up.
Detailed Tune-Up
For the maximum benefit to your Megabitz experience, we suggest some more customization.
Starting in the Latency tab, select the "Modify" button, and then select the Add button to add the URL "news.megabitz.net". We suggest that you delete the other URL's listed as well, as keeping them will throw off the stats and cause non-optimal settings. Select "Ok" to return to the Latency tab, change "How many pings per URL" to 9, and "Packet size" to 1500. Run the test, and make a note of the reported Average on the last line.
Pinging [206.55.72.100] with 1500 bytes ->bytes=1500 time=86ms TTL=62
Pinging [206.55.72.100] with 1500 bytes ->bytes=1500 time=90ms TTL=62
Pinging [206.55.72.100] with 1500 bytes ->bytes=1500 time=92ms TTL=62
Pinging [206.55.72.100] with 1500 bytes ->bytes=1500 time=100ms TTL=62
Pinging [206.55.72.100] with 1500 bytes ->bytes=1500 time=90ms TTL=62
Pinging [206.55.72.100] with 1500 bytes ->bytes=1500 time=90ms TTL=62
Pinging [206.55.72.100] with 1500 bytes ->bytes=1500 time=89ms TTL=62
Pinging [206.55.72.100] with 1500 bytes ->bytes=1500 time=93ms TTL=62
Ping statistics for above hosts:
Packets: Sent = 9, Received = 9, Lost = 0 (0% loss)
Approximate round trip times (RTT) in milli-seconds:
Minimum = 86ms, Maximum = 100ms, Average = 91ms
In this example, the 91 is what you're looking for - it is your average round trip time. Keep it in mind, and select the BDP tab. Enter the speed of your Internet connection in the Bandwidth box, enter the average round trip time (91 in the example) in the Delay box, and select "Calculate." Make a note of the RWIN/BDP size suggested.
Now, select the Largest MTU tab. Use "news.megabitz.net" for the URL. Run the test, and make a note of what it says that you may set your MTU to.
Finally, return to the General Settings tab. Select the network adapter that your Internet connection is on, then select your connection speed, and click on Optimal settings. Verify that the MTU of the Network Adapter is equal to the number that was determined in the Largest MTU tab. Then, compare the BDP tab's suggested RWIN/BDP number to the TCP Receive Window size. These do not have to be identical, but it should not be less than half or more than double. We do not suggest making manual changes using the Custom settings options, however, if the Optimal settings suggested by SG TCP Optimizer differ substantially from what you've calculated, we do suggest that you contact us for additional guidance and analysis.
Do not forget to reboot your PC when prompted to do so.
We've had clients that have been able to download at over 7 megabits per second on a single connection with a properly optimized set of settings.
If you have any questions about this subject, contact us! We're here to help.