In this menu, you can tweak some secondary, less critical settings. These settings rarely need to be modified. If you change them, make sure you understand the consequences of those changes.

Boot Wait Time * : The time period during which you can access the router using its CFE webserver. This refers to the bootstrapping portion of the process, or the loading of code before the operating system loads. If you need to delay the boot process (to stay in internal webserver CFE mode), change this setting.

In rare circumstances, such as a power outage, your modem might take longer to boot than FreshTomato does. This setting could be used to tune that until it is optimal. The asterisk (*) indicates not all hardware models support this feature.

WAN Port Speed * : Lets you set the WAN port to Autonegotiate (default) mode or force a specific speed/duplex combination for it. Only 10Mbps and 100Mbps speeds can be forced. For 1Gpbs, leave this set to Autonegotiate. The asterisk (*) indicates not all hardware supports this feature.

CTF (Cut-Through Forwarding): If checked, this enables Level 1 NAT hardware acceleration.

CTF lets bridges use an alternative forwarding method for storing and forwarding frames. Enabling CTF may improve speeds on Internet plans that offer speeds above 100 Mb/second. CTF is usually necessary to reach peak speeds on plans that allow 200 Megabits/second and higher.

With CTF enabled, the router starts to send transmission frames as soon as the full packet header has been received. However, the router relies on the client device to tell it whether the data is corrupted for resend. This restriction can cause problems with a few common home uses.

Enabling CTF disables QoS and Bandwidth Limiter. It can also cause issues for IPv6 tunneling protocols, like 6in4 Static. This is because the switching part of the packet bypasses parts of the standard Linux iptable chains.

With CTF disabled, the router stores the entire frame before sending it out to its destination.

When this happens:

• The holding period may require more of the router's CPU time.
• WAN-to-LAN performance will depend more on the router model.

CTF/FastNAT is supported as follows:

• ARM Routers (RT-AC68U, RT-AC3200, R7000, etcetera) support CTF.
• MIPS RT-N routers (like the E4200v1, RT-N16) can use Broadcom FastNAT
• MIPS RT-AC routers (like the RT-AC66U) do not support CTF or FastNAT.

FastNAT is a similar function that forwards frames at accelerated speeds.

On ARM devices, you can expect performance in the range of 200 to 400 Mb/s with CTF enabled.

Enable Jumbo Frames: This allows you to increase the maximum frame size on the LAN. (Default: Disabled).

The default Jumbo Frames size is 2 KBytes. If enabled, Jumbo Frame capability will be enabled on all LAN/WAN ports.

This feature is only supported in 1000 Mb/s mode. Also, a gigabit switch uses more memory when this feature is enabled. This will influence system performance, depending on how many switch ports simultaneously use jumbo frames.

Not all hardware models support this feature.

Jumbo Frame Size: If disabled, default frame size is 2 Kbytes. If enabled, its setting overrides default frame size (Default: off).

Generally, enable Jumbo Frames if you frequently transfer large files within your LAN. To function, all devices must support Jumbo Frames. You should also standardize the packet size across all LAN devices.

You are strongly advised to leave this disabled unless there are specific requirements for it. Using Jumbo Frames means Internet traffic will be fragmentaed, unless the end device supports Path MTU Discovery. Often, the limited performance benefits of Jumbo Frames isn't worth the time and effort needed to tune/troubleshoot it.

The asterisk (*) indicates that not all hardware models support this feature.