As part of our contract renegotiation with Verizon, we upgraded our network speed to 35/35 (35Mbps download and upload). When we did a speed test, however, we were only seeing about 20/15. I did some research and found out a few things that, well, it “would have been nice to know yesterday.”

You may need a new ONT. Some subscribers have old ONT (optical network terminal) boxes on the side of their house that can’t actually support the faster speeds. This wasn’t the case for me, but affected folks actually need someone to come out from Verizon and replace the hardware to get the full speed.

Not all speed tests report higher speeds correctly. I lost the links where I first saw this reported, but in the Verizon forums I saw several cases of common speed tests not actually reporting correctly. I saw this myself. Use the Verizon speed test to check your speed.

You may need to change some settings. Apparently Windows default network settings don’t allow the client to fully take advantage of the higher speeds. Verizon has a network optimizer that you can run that will update some settings and get things working correctly (you can also use it to reset your settings back to default). This worked for me on Windows 7, but if you’re on Vista you may need to read this KB article first. The settings it modifies (copied from their description page):

• TCP 1323 Extensions - This parameter enables enhancements to the TCP/IP protocol that provide improved performance over high speed connections.
• TCP Receive Window - This parameter specifies the number of bytes a sender (the source you are downloading from) may transmit without receiving an acknowledgment. Modifying it determines the maximum size offered by the system.
• MTU (Maximum Transmission Units) - The MTU defines the largest single unit of data that can be transmitted over your connection. The FiOS network requires an MTU of 1492 bytes.

After running the optimizer I was able to get 35/35 on wired connections. Wireless connections still report weird for me - like 3/50 or something. It’s nice and fast, though, so I’m chalking that up to incorrect reporting rather than misconfiguration.