Kitz Forum
Broadband Related => Broadband Hardware => Topic started by: neil on November 29, 2019, 03:31:51 PM
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MTU size in modem settings and router settings and PC settings has any effect on pkt loss in games and stuff? please share any suggestions
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As I use an ADSL2 (ITU-T G.992.3) service, with PPPoA, I have the modem/router's MTU configured as 1500.
All devices connected to my LAN have their MTU settings configured as "Auto".
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As I use an ADSL2 (ITU-T G.992.3) service, with PPPoA, I have the modem/router's MTU configured as 1500.
All devices connected to my LAN have their MTU settings configured as "Auto".
whats the difference between PPPoE and PPPoA?
in my modem it is default at 1400. Is it OK?
[Moderator edited to merge two consecutive posts into one.]
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The largest MTU for PPPoA is 1500, for PPPoE it is 1492 - the difference is because of the header contents.
Generally the larger the MTU the better the speed although the difference is marginal. One thing is that the larger each block the higher the possibility it may get corrupted and need re-transmission. Interleaving etc. reduce the likelihood of this so there's no reason these days to not go for the largest that works.
Have you read Kitz's pages about MTU? https://kitz.co.uk/adsl/MTU2.htm
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whats the difference between PPPoE and PPPoA?
There are descriptions of PPPoE (https://en.wikipedia.org/wiki/Point-to-Point_Protocol_over_Ethernet), PPPoA (https://en.wikipedia.org/wiki/Point-to-Point_Protocol_over_ATM) and PPPoEoA (https://en.wikipedia.org/wiki/Point-to-Point_Protocol_over_Ethernet#Use_with_DSL_%E2%80%93_PPPoE_over_ATM_(PPPoEoA)) available on Wikipedia, which should answer your query far better than anything I could type.
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For me mtu is about compatibility more than anything.
As jelv said the performance differential from a few bytes isnt going to be noticeable, the issues with mtu is always about fragmentation handling.
I had a discussion on pfsense recently about ipv6 mtu in which I said everyone should have just used 1280 as thats compatible with all types of broadband and tunnels, but companies like cloudflare and a few users have started migrating to 1500 which in my view will just create the same issues as ipv4 had down the line.
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in one game pubg i do get pkt loss on upstream and after google search there were some posts about MTU size
i tried setting different MTU size but i still face pkt loss
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Hi
Please remember MTU is limited usually by your dsl provider and some modems-routers cannot be set to mtu 1500
Who is your dsl provider
Many thanks
John
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Hi
Please remember MTU is limited usually by your dsl provider and some modems-routers cannot be set to mtu 1500
Who is your dsl provider
Many thanks
John
i am from Pakistan and the highest MTU i can set in my modem is 1492 but after setting this vlaue my pkt loss increased so i set it at 1480 for now but i still face pkt loss in pubg lite before it was default at 1400
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Hi
Many thanks
Please could I ask how you know you have packet loss
If 1492 gives fragmented I would think 1480 would also
So first you need to do the following test from your computer
(As MTU is set at 1480 in router, do not go above 1480 as it will fail)
ping bbc.co.uk -f -l 1440
If 1440 gives fragmented lower it until you find the MTU value without fragment then set your router MTU to that value.
Restart router and test once more
To find where packet loss may be happening run from command prompt
pathping bbc.co.uk
The result should show you where your packet loss is occurring
Many thanks
John
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Hi
Many thanks
Please could I ask how you know you have packet loss
If 1492 gives fragmented I would think 1480 would also
So first you need to do the following test from your computer
(As MTU is set at 1480 in router, do not go above 1480 as it will fail)
ping bbc.co.uk -f -l 1440
If 1440 gives fragmented lower it until you find the MTU value without fragment then set your router MTU to that value.
Restart router and test once more
To find where packet loss may be happening run from command prompt
pathping bbc.co.uk
The result should show you where your packet loss is occurring
Many thanks
John
i have turned on ping and other stats in game settings it shows pkt loss for upstream 1-10-15% and sometimes it hit 50% during start of game for downstream it is all fine
and i am getting fragmented after 1452
>ping bbc.co.uk -f -l 1453
Pinging bbc.co.uk [151.101.0.81] with 1453 bytes of data:
Reply from 192.168.1.1: Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
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Hi
So you need to set router MTU to 1452 and restart router
Then run pathping to see where packets are lost
Many thanks
John
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Hi
So you need to set router MTU to 1452 and restart router
Then run pathping to see where packets are lost
Many thanks
John
i read somewhere 18 bytes are overhead for header and other stuff
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For me mtu is about compatibility more than anything.
As jelv said the performance differential from a few bytes isnt going to be noticeable, the issues with mtu is always about fragmentation handling.
I had a discussion on pfsense recently about ipv6 mtu in which I said everyone should have just used 1280 as thats compatible with all types of broadband and tunnels, but companies like cloudflare and a few users have started migrating to 1500 which in my view will just create the same issues as ipv4 had down the line.
I'm guessing from a backhaul perspective, a 1500 MTU is going to be lighter on the CPU of the routers plus more efficient use of bandwidth?
So I guess Cloudflare are going to be more concerned with keeping the costs of their network down rather than end-user issues.
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Hi
So you need to set router MTU to 1452 and restart router
Then run pathping to see where packets are lost
Many thanks
John
path ping ends after 2 hops my routerand modem. 100% pkt loss at modem because it is in bridge mode?
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Hi
If your modem is correctly in bridge, ping would not ping it
It should be
Pc
Router
Gateway
Etc...
Probably best to post your pathping
Many thanks
John
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Hi
If your modem is correctly in bridge, ping would not ping it
It should be
Pc
Router
Gateway
Etc...
Probably best to post your pathping
Many thanks
John
i have installed pingplotter and here is pingpath
pathping google.com
Tracing route to google.com [216.58.207.110]
over a maximum of 30 hops:
0 DESKTOP-********* [***********]
1 192.168.1.1
2 * * *
Computing statistics for 25 seconds...
Source to Here This Node/Link
Hop RTT Lost/Sent = Pct Lost/Sent = Pct Address
0 DESKTOP-****** [*********]
0/ 100 = 0% |
1 0ms 0/ 100 = 0% 0/ 100 = 0% 192.168.1.1
Trace complete.
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Hi
Many thanks and whatever is at hop 2 is blocking or dropping ping
Can you post the following output
tracert google.com
Many thanks
John
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Hi
Many thanks and whatever is at hop 2 is blocking or dropping ping
Can you post the following output
tracert google.com
Many thanks
John
hop 2 is my modem in bridge mode
tracert google.com
Tracing route to google.com [172.217.19.14]
over a maximum of 30 hops:
1 <1 ms <1 ms <1 ms 192.168.1.1
2 * * * Request timed out.
3 4 ms 5 ms 9 ms 182.187.0.1
4 5 ms 5 ms 5 ms 182.184.2.201
5 5 ms 5 ms 5 ms 182.176.139.181
6 28 ms 28 ms 28 ms 10.0.4.158
7 28 ms 27 ms 27 ms static-10GE-KHI275-P01-SwA.pie.net.pk [202.125.128.173]
8 27 ms 27 ms 27 ms 10.253.4.8
9 45 ms 46 ms 45 ms 74.125.119.252
10 50 ms 50 ms 50 ms 108.170.247.17
11 46 ms 46 ms 46 ms 209.85.249.155
12 49 ms 49 ms 49 ms zrh04s08-in-f14.1e100.net [172.217.19.14]
Trace complete.
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Hi
Sorry your modem is not on bridge mode then i believe
If modem was in bridge mode, it would tunnel between isp and router, where router serves pppoe and tunnel is not pingable and should not show up or block any pings
As tracert shows it entering out, the hops past hop2 should also show in pathping so hop3 hop4 etc...
I could of course be wrong as you are in a different country
Many thanks
John
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Sorry to disagree, John, but a modem in bridge mode can be pingable. My modem is in bridge mode, but it also has a LAN connection through which I gather the stats. If I ping its IP address I get an immediate return.
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Hi roseway
Many thanks
Sorry I believe you are pinging the modem lan and not the modem bridge
To test this, if you pathping bbc.co.uk you should not see your modem IP address in this case whereas Neil is showing his modem at hop2
I suspect but could be wrong it is not full bridge (natd and told to block pings)
As I said, I could be wrong sorry
Many thanks
John
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Yes, you're probably right. I was just pointing out that the fact that a ping to the modem gets a response, is not of itself an indication that the device is misconfigured.
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Hi Roseway
Many thanks
Yes, sorry your correct but it would indicate the modem is not in bridge mode.
As you know, we use hg612 in bridge mode and have lan 2 enabled for stats, so a tracert from one of our computers shows as below (note no modem is shown in hops) but a modem in nat'd mode would show in hops (see hop1 (192.168.18.1) nat'd edge router)
The hg612 lan 2 is 192.168.1.2
Many thanks
John
tracert bbc.co.uk
Tracing route to bbc.co.uk [151.101.0.81]
over a maximum of 30 hops:
1 1 ms <1 ms 1 ms 192.168.18.1
2 1 ms 2 ms 1 ms 192.168.1.1
3 16 ms 15 ms 15 ms host81-139-96-1.in-addr.btopenworld.com [81.139.
96.1]
4 15 ms 15 ms 15 ms 213.120.182.141
5 17 ms 15 ms 17 ms 213.120.161.82
6 17 ms 16 ms 16 ms 213.120.182.65
7 17 ms 16 ms 16 ms 31.55.164.107
8 16 ms 16 ms 16 ms 109.159.248.93
9 19 ms 19 ms 19 ms 194.72.16.246
10 22 ms 30 ms 21 ms peer7-et-0-0-5.telehouse.ukcore.bt.net [109.159.
252.184]
11 * * * Request timed out.
12 21 ms 19 ms 19 ms 151.101.0.81
Trace complete.
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i have also setup 2nd connection which is dynamic ip so i can see my modem stats
maybe that's why i am getting this error in pathping
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Hi
I am sorry I do not know what your using router and modem and I have no idea over your country broadband
However, if modem is correctly in bridge mode, then the bridge (tunnel) does not have an IP address of any type
So in bridge mode, would not show in the list (take a look at my tracert - no modem is shown as it is in bridge mode)
If you have setup a lan port to see modem stats, which a lot do including myself, then you would only be able to see this in the tracert if you were connecting using nat’d mode and not bridge mode
There are 3 things though which come to mind as follows
Have you changed any setting on the modem eg firewall QoS etc... if so, this could cause issues depending on your changes
On your router, have you setup both pppoe and static/dynamic connections to modem - if so, and your modem is in bridge mode - stop your static/dynamic setup
The last is what you refer to as modem on hop 2 - could this be your isp gateway - if so, it is out of your control
As I said though, I could be wrong as I do not know what requirements your country use
Many thanks
John
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I am sorry I do not know what your using router and modem and I have no idea over your country broadband
i think it is same as UK vdsl2 nothing special i have modem from ISP which is connected with splitter and modem is in bridge mode and i am dialing pppoe connection from router and router is tplick archer c7.
Telephone wire is 2 pair wire same as UK twisted pair wire coming from pole i have seen in videos
same technology vdsl2 same frequencies but just lower speed packages
[Moderator edited to remove a large section of the preceding post from the quotation.]
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here is pingplotter for google.com
[Moderator edited to remove the unnecessary quotation of an earlier post.]
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i did a modem restore to factory and then added bridge mode it is still same for pathping stops at hop2
[Moderator edited to remove the unnecessary quotation of an earlier post.]
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Hi
I am inclined to think it is the isp gateway then (option 3 of my thoughts I posted)
If that is the case, you would need to clearly document your upstream packet loss and report it to your dsl provider
They may or may not correct the packet loss
Appreciate an update when you have contacted your provider
Many thanks
John
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Hi
I am inclined to think it is the isp gateway then (option 3 of my thoughts I posted)
If that is the case, you would need to clearly document your upstream packet loss and report it to your dsl provider
They may or may not correct the packet loss
Appreciate an update when you have contacted your provider
Many thanks
John
ok but can you tell me difference between isp gateway and modem?
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Hi
I suppose the easiest way to understand in a laymen term would be to view the bridge (modem) as a switch between your router and isp gateway
This is not the case if using nat
Many thanks
John
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Hi
I suppose the easiest way to understand in a laymen term would be to view the bridge (modem) as a switch between your router and isp gateway
This is not the case if using nat
Many thanks
John
if you have config your modem and router in bridge mode then how you keep an eye on your modem stats?
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With the BT modem HG612 we have a cable from LAN1 to the router WAN port for the bridge and a second cable from LAN2 to a LAN port on the router. It depends on the modem/router having a second port which is addressable via a LAN IP address.
(https://kitz.co.uk/routers/images/hg612_cables.png)
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With the BT modem HG612 we have a cable from LAN1 to the router WAN port for the bridge and a second cable from LAN2 to a LAN port on the router. It depends on the modem/router having a second port which is addressable via a LAN IP address.
(https://kitz.co.uk/routers/images/hg612_cables.png)
my lan slots are all occupied
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Hi
@neil - in previous posts above you stated you were already monitoring stats from a second connection!
So I am not clear over your last few posts asking how to monitor modem stats and no lan slots available!
Many thanks
John
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Hi
@neil - in previous posts above you stated you were already monitoring stats from a second connection!
So I am not clear over your last few posts asking how to monitor modem stats and no lan slots available!
Many thanks
John
you people are using two ethernet cables and i am using one cable connected to wan port on router that's why i asked
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It might be possible depending on your router and modem. If you follow some of the links from this (https://kitz.co.uk/routers/hg612unlock.htm#bridge) section of the Kitz guide you should get some idea of the complications!
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Hi
@neil - in previous posts above you stated you were already monitoring stats from a second connection!
So I am not clear over your last few posts asking how to monitor modem stats and no lan slots available!
Many thanks
John
looks like isp did something and now my modem is in true bridge mode as you mentioned
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Hi
If your modem is correctly in bridge, ping would not ping it
It should be
Pc
Router
Gateway
Etc...
Probably best to post your pathping
Many thanks
John
ISP fixed it i think ping is now going to router gateway
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it is again back to 100% pkt loss for modem