Multiplayer Lag Issues

[Bago]

Been playing multiplayer with a friend for a couple weeks and recently starting roughly around late last week we started noticing an issue where whoever was not the host was getting significant 10+ sec lag on any action when joined to the host server.

We've checked out tracert to each other, all nodes look normal. We have no issue connecting to one another so I don't think its a firewall issue. Tried disabling anti-virus, to no avail.

Not sure whats going on, was working fine up until last week and has been a constant problem since that time.

[Deralicte]

I recently returned to Grim Dawn for this latest DLC, and me and my friends are experiencing the same thing. I've never experienced lag while playing this game before, but now it seems like multiplayer is unplayable, we might play for 15-20 minutes then the lag gets worse and eventually hard locks our computers if you arent the host.

[Molkan]

Yeah, and my friend and I have the same thing, 10-12 seconds delay.

[Bago]

still happening as of 5/17/2019, bump

[mikeydsc]

Look for this file here
...\Documents\My Games\Grim Dawn\Settings
Goto your GD settings file and change * UPNPenable = false *
If this line is not there add it to end of the file and save. Make sure you do have permissions to do this or the change will not take.

If you are behind 2 or more routers, this can cause issues as well. If anyone is using wireless, this can also cause issues. Host should never be on wireless.

This helps in single player for some lag/rubberbanding issues. All players in your game needs to try this.
Lag is usually caused by hosts upload bandwidth. More players there are in game. more noticable it is.

[Bago]

We will give the change a shot and report back. Thanks for the suggestion.

Originally posted by mikeydsc:

Lag is usually caused by hosts upload bandwidth. More players there are in game. more noticable it is.

I am hosting on a 1gbps connection up/down so I don't think that is the issue. He's on a 50/50mbps and I have the exact same problem when he hosts. I need to find other people to test against. Only reason I haven't done that before hand was we played for weeks with no issues and it seemingly came out of nowhere.

[Bago]

Alright so we did this, but no luck. He was able to connect again but lag was intermittent, seemed fine in Forgotten Gods for him, but when we went to homestead and other main campaign areas his game started lagging a lot, these are all places we've been together before as well with no issue.

I did manage to get him to crash when we tried Crucible mode with one another. Here is the dump he sent to Crate, I've scrubbed out the steam ids, etc:

0: 264057/1000000000 bytes of cloud storage used
812: UPnP services not available.
812: UPnP services not enabled.
812: Public IP (RouterServices): INVALID
812: Bound control socket (handle 2576), on 192.168.1.120:42804
812: Initializing Client on Host DESKTOP-XXXX (192.168.1.120)

1664: UPnP services not available.
1664: UPnP services not enabled.
1664: Public IP (RouterServices): INVALID
1664: Bound control socket (handle 2576), on 192.168.1.120:42804
1664: Initializing Client on Host DESKTOP-XXXX (192.168.1.120)

2119: Bound connection to STEAM:XX:1837322
2119: Creating connection to remote address STEAM:XX:1837322
2119: Starting Address resolver for connection to STEAM:XX:1837322
2289: Sending connect request from STEAM:XX:1837322 to STEAM:XX:0
2418: Received Server Connect Ack Packet from 192.168.1.243
2418: Client is assigned hostID 1
2418: Sending ConnectionVerifyPacket to server.
2520: Packet (SpawnPlayerPacket) exceeds MTU of 1400. Fragmenting into 8 fragments.
8734: Lost Connection with Server, Disconnecting.

[mikeydsc]

2520
packet exceeds MTU of 1400. (MTU - max transmit unit)

Either game is creating a bad packet or you can try this tool to increase it to 1500.

https://www.speedguide.net/downloads.php

Set the MTU of your internet connection to 1500 and try again.
My networking skills are rusty, but iirc, routers can handle upto 1500 MTU by default.

In determining your network’s MTU size, you’ll need to know the following information to understand the concept of using certain commands through the command prompt.

• Ping: a command to determine the connectivity between your computer and a particular address (within the Local network or the internet).

• URL or local address: the web address or the IP address of the server you’re trying to check for speed connectivity.

• -f: a command to make sure that when you ping a certain address, it will not fragment the packet sent or received.

• -l: a command commonly known as a packet size switch. This is the best command to help you determine the best MTU size for your network.

• xxxx: the packet size (value) which you will test. You can start from 1472 until you can reach the exact packet size which will not result to the prompt “Packet needs to be fragmented but DF set.” You may decrease the value by 10.

Here are the results that you may get after doing the ping test:

• Four replies received: This means that the packet size entered is either within or the actual MTU size used within your network.

• Destination net unreachable: This means that there was no path or route to the destination or the address.

• Request Timed Out: This means that within the default wait time period (1 second), there was no response.

• Packet needs to be fragmented but DF set: This means that the packet size you entered is too high for your MTU value.

[anachoret]

Originally posted by mikeydsc:

2520
packet exceeds MTU of 1400. (MTU - max transmit unit)

Either game is creating a bad packet or you can try this tool to increase it to 1500.

Grim Dawn defaults to 1400 MTU in options.txt, and Zantai et al. have made it sound like that is normal, default, expected, and correct.

https://steamcommunity.com/app/219990/discussions/0/1456202492168167998/#c1456202492169467642

My Documents\My Games\Grim Dawn\log.html is littered with:

Packet (AllPlayersHeartbeatPacket) exceeds MTU of 1400. Fragmenting into 2 fragments.
Packet (SpawnActorPacket) exceeds MTU of 1400. Fragmenting into 2 fragments.
Packet (AllPlayersBasicInfoPacket) exceeds MTU of 1400. Fragmenting into 3 fragments.
Packet (QuestCommandDeclareTokensPacket) exceeds MTU of 1400. Fragmenting into 8 fragments.
Packet (SpawnPlayerPacket) exceeds MTU of 1400. Fragmenting into 20 fragments.

[mikeydsc]

Yes. it can exceed that, but how much is it exceeding it by? That is the question. Its known as a malformed packet, and if its too large it will end up crashing the IP stack sometimes.

[anachoret]

Whether correct or not, Grim Dawn is the one doing the choosing of both packet size and what is put into the packets.

[mikeydsc]

Not true, GD sends the data to the IP stack which sends the info out onto the wire. GD sets an initial value that you can override with MTU settings.

Read up on the OSI model.

[Bago]

Alright so I tried to join a handful of games on the general public list and had similar issues with about half of the servers I tried while some had no issues at all. So might just be a case by case issue.

Friend is going to get a new router soon, maybe this will resolve the issue. :\

[Bago]

Alright so just wanted to update the thread with the solution:

Seems like it was a router issue with my friend. His old Linksys router apparently broke randomly and his new one, an ASUS RT-ACRH17 seems to have fixed the issue. Not sure if that helps anyone, but if someone is having issues check your routers.

edit: I'll try to get the old router model number as well.

[mikeydsc]

Allot of the old routers said they supported upnp, but in reality it was more of a box saying than actual reality. The support was terrible.

[Juravis]

Came here after a search because my Grim Dawn kept blurting 1400 MTU, fragmenting...
Changed the setting to 1476, issue solved.

This will hopefully result in better performance in multiplayer because I was wondering why my FPS drops massively with lots of players but changing the video settings during play never helped.

Thanks to everyone for the info, found out via PING that my packet fragments at 1477. I'm also using UPNP and the router itself is set at 1500.

I don't know if it's a European thing but the standard size in North America SEEMS to be 1476, why default to 1400?