Slow speeds when using modem mode

[speedsbadman]

I recently upgraded my broadband only package from M350 to Gig1.

Upon setting up my Hub 4 I plugged a CAT6 ethernet cable into it and ran a couple speed tests.

The peak result I got was 943 Mbps (not too shabby but a little off the expected speed range of 1077 - 1139 Mbps).

After that I put the Hub 4 into modem mode and connected it to my Netgear Nighthawk R7000.

Two things I noticed after switching the Hub 4 to modem mode.

1. My public IP address switched back to old public IP address (before I upgraded to Hub 4).
   
2. My peak download speed went from 943 Mbps to dead on 362 Mbps (the old speed I was getting on the M350 package).
   

I know the issue must be to do with how the Hub 4 is registered on the WAN network because if switch the Hub 4 back to router mode my public IP switches back to what it was before and Gig1 speed returns.

If I connect my Netgear Nighthawk R7000 in bridge/switch mode to the Hub 4 I get effectively the same speed as I would if I was connected directly to the Hub 4.

So I've ruled out it's a fault between the two.

Any ideas why my public IP address and speed changes when putting the Hub 4 into modem mode.

[Adduxi]

When in modem mode, it's the MAC address of the Netgear that determines the WAN IP, hence the change of Hub see's no change.

However, when in Router mode, the Hub 4's MAC address gets a new WAN IP.

You could try and clone a new MAC address on the Netgear and this will get a new WAN IP when in modem mode.

[speedsbadman]

I ended up fixing the issue, posting the solution for anyone else who gets stumped.

One thing I failed to mention in my initial post is that my Netgear Nighthawk R7000 router is running the FreshTomato custom firmware (highly recommend it if you have a compatible router).

It appears I needed to enable the CTF (Cut-Through Forwarding) under Advanced > Miscellaneous.

If this option isn't enabled your router may be bottle necking your WAN speeds, see the following description taken from the wiki.

CTF (Cut-Through Forwarding) If set, this will enable hardware acceleration. For example, this would allow you to use your FreshTomato device in a WAN Gigabit environment. With this option disabled (Default), your WAN-to–LAN performance will depend on the hardware model in use. You might get anything between 200~400Mbps on ARM devices. NOTE: Enabling CTF will disable QoS and Bandwidth Limiter, since the switching part of the packet bypasses parts of the standard Linux iptable chains.

https://wiki.freshtomato.org/doku.php/miscellaneous

Hope this helps anyone else experiencing this issue.

[Geoff_UK]

I may be wrong, but you’re unlikely to get more than 950Mbps as the WAN port on the hub 4 is gigabit - I believe the hub 5 has a 2.5 gig WAN port. 

even with the hub 5, to see 1,100 Mbps, you would need a faster than gigabit infrastructure on your LAN side ?

[Adduxi]

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@Geoff_UK wrote:

<snip>    even with the hub 5, to see 1,100 Mbps, you would need a faster than gigabit infrastructure on your LAN side ?

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Correct, you would need to move to 10GB switches etc.  950 is about tops for 1GB ethernet.  Some routers do have 2.5GB WAN ports, and you could always put a 2.5GB NIC into a PC if you wished.