MTU for XBOX live mutliplayer gaming on 5g home broadband

[Lexx289]

I am struggling to get my Xbox to work on Xbox live. Doing some googling it seems that the MTU is too low, it is 1360 and should be about 1385 to be able to work properly. I have rung three who seem to have no knowledge of what an MTU is and have sent me to the ombudsman. I have logged into the router (H122-373) and increased the MTU manually however it will not pull through onto my XBOX. I have put it in the DMZ, enabled UPNP and generally faffed with it as much as i can but the MTU on the XBOX does not change. I am assuming this is what is being sent from three and so it is something to be changed at three's end...

Does anyone else have any experience of this, or have any issues with XBOX live and home broadband 5g? or can they get it to work, cheers

[NobodyUK]

Try changing your APN from 3internet to three.co.uk. The MTU should then be stable at 1472.

Three's support are useless. Most of them don't even know what the MTU is. But it's being limited on the APN they have set up for the home routers (three.co.uk is the phone network).

[TylerM95]

Hi all,

having this same MTU problem, says I need 1384 or higher but when I test speeds I’ve only got 1360 MTU. I have the MC888 5G hub and it’s setup with a wired connection to my Xbox. 

I spoke to someone on live chat and they said there’s nothing they can do, I’d need to go to someone in store so they can take a look at it. Is there anything that can be done? 

this is the only reason I bought it so will just return if I can’t resolve the issue.

[Joemac1999]

Also having what I believe to be the same issue. My friend and I live next door to each other, both with Three 5g broadband and have both been experiencing major lag spikes and high latency. Neither of us had issues with it before and both been with Three for 2 years. Only issue I can identify is with MTU. Issues have been ongoing for about a week now

[NobodyUK]

Youmight be able to get the MTU up to scratch and then keep a ping going sending packets at 1492 bytes. You have to keep pinging with a slightly higher value until you reach the max.

I'm not sure if it would apply to all devices on the LAN though.

Using "three.co.uk" APN does seem to keep the proper MTU size. I think the option is under broadband and then cellular APN.

[Kal]

That's helpful, NobodyUK, that you've found our exactly what is happening in terms of the MTU increasing to a decent/required level but then backing off when the connection is idle for any period. I can see that some systems/programs will need the MTU from their initial start-up.

I wonder if there's a way to kick off something like a ping, on another computer on the network, that can keep the connection going with the higher, necessary MTU value.

You say that it's possible to get a good MTU with a different APN.  Does it stay good consistently?

My APN is (I think) showing as '3internet' and is one of 2 APN listed, though only APN1 is enabled.  It came pre-configured on the NR5103E box from Three.  I notice that it also lists a PDP Type of IPv4/IPv6.  I have tried to change it to IPv4 only, but then the entire connection doesn't work.

Do you fancy putting up some clear instructions for folks on exactly how to reconfigure their router, so as to get better performance?  Given the lack of any response or input from Three, it looks like they are not planning to address this issue.

[NobodyUK]

Yep this is ongoing. From tests I can see that the MTU will slowly increase to the proper level when you open a connection, but then it seems to quickly back down when the connection is idle again. I'm guessing they are doing this as a cost cutting exercise to save bandwidth, but it causes issues as many programs expect the MTU to be high enough to begin with.

If you switch to the "three.co.uk" APN you get a good MTU, but then port forwarding will not work (as IPing is different on the mobile network) so if you want to host a server you can't.

[ZaneMD11]

Having the same issue. Interestingly, I had this Xbox party chat/MTU issue with my Three 4G router like a year ago and then I upgraded to the 5G. Figured that was the reason. Smooth sailing for nearly a year afterwards UNTIL this past March 2024 where, although I have no problems getting into multiplayer games, the party chat will simply not connect most of the time. This came out of nowhere. And still registering an MTU problem where I can only pick up a 1360 (whatever that means) although I don’t think this particular problem ever went away. Sometimes the party chat WILL work but maybe only for an hour or two before it automatically disconnects and maybe this will occur at a frequency of 1 out of every 5 gaming sessions I participate in but regardless, most the time the party chat doesn’t work. Absolutely maddening. Can’t understand why this particular aspect of my on-line play is failing on this network. Perhaps Three can give us an update? @KateS 

[JMiquel]

I recently have come across this same issue, where I cannot access online games or connect to multiplayer because my MTU is too low. Strangely, I had the older Three 5g hub for over a year prior to being told to switch to the new ZTE hubs, and I had 0 problems. Even with this new ZTE hub, I had no problems for about 6 months, but then all of a sudden over the past 2 weeks, I cannot connect to multiplayer games, with the problem being too low MTU. I'm guessing by reading all the previous messages that there isn't really any way to fix this, so definitely looking to change the hub, which is a shame. 

If a solution is found, would love to hear about it!

[Kal]

Update: We have found that connecting a Nintendo Switch also flags up a problem with the internet connection on some games.  It seems to be the MTU issue.

Interestingly, when connecting it to a wifi hotspot on an iPhone with the Smarty network (which is a MVNO sitting on Three, owned by Three as I understand) then it will work.  But through the Zyxel NR5103E it will not work.

Anyone got any news about this?

[ZaneMD11]

So having a Switch connected to the network affects the MTU? I’m having the same issues with Xbox as you all and also have a Switch on the network.