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How do I get full speed from BT Fiber 1GB Broadband

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Col8eral

Regular Contributor
I have an ASUS RT-AX88U running ASUSWRT-Merlin 386.3_2.

I have just had BT Full Fiber 1GB installed.

Using the supplied BT hub I get 850mb/s

Using my ASUS router im getting 650mb/s.

(Both tests via ethernet connection to lap top).

Could someone advise me of settings I need to change to optimise the speed.

Currently I set WAN Connection type to PPPoE, both MTU and MRU set to 1492 (default), Enable VPN + DHCP Connection set to yes.

The ASUS router network map summary shows WAN as 1 Gbps

Any thoughts on how I can get my lost 200mb/s back?

,
 
WOW. Tunred of QoS and it went up to 850mbps. Thanks alot.

Thats a massive 200mbps overhead for that service!!!!

Thanks again
No need QOS if speed download more than 400Mbps.. unless your upload is below 20Mbps with current download speed and you always have someone upload something..
 
Where did you do those optimizations?
 
I did a ping test with a payload of 1500 and reduced it by 10 until there was no packet loss once I found the maximum size with no loss I added 28 to account for the payload header and that was my MTU. For MRU I did the same but pinged my router from a remote location.

From the PC command line use the following format

ping www.yahoo.com -f -l 1492

I flowed this guide on YouTube which did the trick for me
 
Last edited:
I have an ASUS RT-AX88U running ASUSWRT-Merlin 386.3_2.

I have just had BT Full Fiber 1GB installed.

Using the supplied BT hub I get 850mb/s

Using my ASUS router im getting 650mb/s.

(Both tests via ethernet connection to lap top).

Could someone advise me of settings I need to change to optimise the speed.

Currently I set WAN Connection type to PPPoE, both MTU and MRU set to 1492 (default), Enable VPN + DHCP Connection set to yes.

The ASUS router network map summary shows WAN as 1 Gbps

Any thoughts on how I can get my lost 200mb/s back?

,

if your isp uses PPPOE you don't need to enable VPN + DHCP connection on wan unless your isp support or needed this.
I also have ax88u whit the latest stable merlin and when I was whit 1 Gpbs fiber and QoS enabled I'm getting 970-980 download and 100 upload
there is something whit your isp modem, I'm guessing that you have some fiber to rj45 or the isp hub configured in bridge mode,
my connection is simple I have sfp to rj45 converter connected to ax88u and that is.

most isp whit fiber they don't allow any other converters or SFP unless it's from the isp itself.

also what type of fiber do you have? GPON or P2P?
 
if your isp uses PPPOE you don't need to enable VPN + DHCP connection on wan unless your isp support or needed this.
I also have ax88u whit the latest stable merlin and when I was whit 1 Gpbs fiber and QoS enabled I'm getting 970-980 download and 100 upload
there is something whit your isp modem, I'm guessing that you have some fiber to rj45 or the isp hub configured in bridge mode,
my connection is simple I have sfp to rj45 converter connected to ax88u and that is.

most isp whit fiber they don't allow any other converters or SFP unless it's from the isp itself.

also what type of fiber do you have? GPON or P2P?
Hi - thank for your reply.

I'm in the UK and have 1GB fiber to the home from British Telecom; BT. Openreach installed an end point inside the house and then using an RJ45 ethernet cable to their supplied router.

I replaced their router with my AX88U using the RJ45. The only way it would connect was via PPPoE and a username and password.

How can I find out if I have GPON or P2P and how would that change my settings?

Many thanks
 
update: looking at the end point in the house there are three lights and three connector. The lights are labled Power, PON and LAN.

Should I get a spf to RJ45 connector. Will any work or is there a specific one?
 
Essentially you can't replace the Openreach ONT (Optical Network Termination) - just use an ethernet cable from the ONT to the WAN port on your AX88U as you are doing.

You said you got it up to ~900Mbps - which is about the maximum your service can provide.
 
I have the same router and BT connection Full Fibre 900. My lan keeps dropping every couple of days for no reason, only a reboot fixes it.

Any ideas?
 
Are you using LAN ports 5-8? Don't. Use a switch instead.
 
Are you using LAN ports 5-8? Don't. Use a switch instead.
I was using ports 4 and 5 only (I just plugged them in randonly when setting up. I've changed the Port 5 to port 1 now. I'll see how it goes. Thanks
 
update. got it up to 900mbs by optimising the MTU and MRU settings

900 is about the best you can expect on a 1G handoff with overhead, so you're good to go. On a LAN you can get it up to about 950 in some cases, maybe a tad more with jumbo frames) but the way shared fiber (which uses TDM) and L3 routing works adds some extra overhead beyond just L2 switching.

If you have 1G in both directions, as another person mentioned, QOS is not needed. I believe BT gig is 1G symmetrical (I work for them, but not in the consumer division so not positive).
 
if your isp uses PPPOE you don't need to enable VPN + DHCP connection on wan unless your isp support or needed this.
I also have ax88u whit the latest stable merlin and when I was whit 1 Gpbs fiber and QoS enabled I'm getting 970-980 download and 100 upload
there is something whit your isp modem, I'm guessing that you have some fiber to rj45 or the isp hub configured in bridge mode,
my connection is simple I have sfp to rj45 converter connected to ax88u and that is.

most isp whit fiber they don't allow any other converters or SFP unless it's from the isp itself.

also what type of fiber do you have? GPON or P2P?

If you're using Verizon or Frontier (not sure about others), they actually have a 1.25G connection to the ONT so you're only dealing with L2 overhead at that point. 980 is still high, but keep in mind most speed test sites nowadays fudge the numbers a bit to give you the total throughput including overhead, where if you did a file transfer you'd see a lower number since it only reports the actual data transferred excluding overhead, you'd probably be in the 900 to 950 range for actual payload.
 

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