QoS Adaptive, confused what to select for WAN packet overhead?

[Netbug]

Hey

I setup my new RT-AC86U (previously used rt-68u), i got a media streaming box running over router vpn client 1, i've never used QoS before but know of some of it's problems, i don't want any complexity i just want to ensure i give priority to the streaming media box. Will it even work seeing vpn traffic is encrypted so won't know it's streaming?

First i went to Adaptive QoS > Bandwidth Monitor and dragged 'Highest' priority onto media box. Next went to Adaptive QoS > QoS. Where it says 'WAN packet overhead' I got the following options, i am on fibre connection and my isp does not require username/password (all automatic), what option do i choose? very confused.



I looked at this link from merlin https://github.com/RMerl/asuswrt-merlin/wiki/QoS-Queue-Disciplines and choose fq_codel as it seems to be the one recommended i think from the above link. But don't understand the 'WAN packet overhead' option.

Cheers.

 

[Pit_g]

(DOCSIS, VDSL or ADSL2), or leave it to 0.

leave it to 0.

Maybe?

 

[john9527]

@RMerlin

Not related to his question, but looks like an HTML error on that page ('</option' in the next to last selection in the pulldown)

 

[Netbug]

(DOCSIS, VDSL or ADSL2), or leave it to 0.

leave it to 0.

No?

I have a VDSL2 (fibre) connection. what i mean is those in the drop down menu. I still thought you had to choose something from the dropdown menu, no? still confused by the options. Not even sure it will work? as it run via vpn client 1 on router?

@RMerlin

Not related to his question, but looks like an HTML error on that page ('</option' in the next to last selection in the pulldown)

Yeah looks like it.

Cheers.

 

[vango44]

I'm pretty sure your media box running through a vpn will not get top priority. It will get categorized as "general" (web surfing) or "other".
After you figure out what it is, you could try moving that category to the top.
I've just been using automatic & sfq option (no WAN overhead options) and it works fine for me.
You can also try selecting a WAN overhead option and then run some tests.
http://www.dslreports.com/speedtest is a good test to try.

 

[Netbug]

I'm pretty sure your media box running through a vpn will not get top priority. It will get categorized as "general" (web surfing) or "other".
After you figure out what it is, you could try moving that category to the top.
I've just been using automatic & sfq option (no WAN overhead options) and it works fine for me.
You can also try selecting a WAN overhead option and then run some tests.
http://www.dslreports.com/speedtest is a good test to try.

I checked the Adaptive Qos > QoS Statistics and at first it looked as though it was being categorized as Web Surfing, i was watching it whilst streaming, then it went weird and reset then it appeared it was showing categorized as 'video and audio streaming' and now the stats show both web surfing and and video and audio streaming as being nearly on par with approx 6MB difference, so i don't know what to belive as if i go to Adaptive QoS > Bandwidth Monitor and whens streaming it was showing as 'web streaming' and if in kodi showing as kodi even though i didn't think it would know as it's defo connected to the vpn. So confused, maybe @RMerlin knows?

I got it set to customised with Web Surfing being highest then Video and Audio streaming second highest as not sure what to believe from QoS statistics.

Regarding selecting a WAN overhead i not got a clue what to select? as described above, what does it do/mean?

Thank you.

 

[FreshJR]

Data is sent using packets.

Think of each data packet as a "letter" you "mail" that is limited to 1500 characters.
Your bandwidth speed is limited using a "characters/second" meter.

QOS explanation:
After you soon as you exceed your "characters/second" bandwidth, your ISP will then start throw out packets to keep your speeds in the range you pay for.

Now the idea of QOS is to put a 2nd meter also counting "characters/second".
The difference is that this 2nd meter is in your control.

This 2nd meter should be set at and trigger at a slightly lower "characters/second" setting than your ISP meter

This after triggering your own meter, YOU can decide what packets to throw out instead of your ISP throwing out random packets. Since you decide what "mail" to throw out, you can intelligently decide to throw out "non-important / critical / bulk" mail. This will ensure smooth operation of your "high priority mail".

---

Packet explanation:
So once again, your "packet" is limited to 1500 charcters.
The first 20 characters are the sender/receiver address.
The next 20 characters are the sender/receiver name (aka more than 1 person lives in your household).
The remaining 1460 characters are your message.

As can infer, it is not efficient sending a 100 character message since you have 40 characters fixed of overhead.
So when sending a 100 character message, 28% of your bandwidth is used for overhead and 72% is used for your message.
Sending the max 1460 characters will have 2.6% of your bandwidth go to overhead, with 97.4% go to your message.

--
Meter Explanation:
QOS accounts for these overheads just mentioned with it's meter reading. These overheads are NOT an issue.
There additionally is also another 36 character overhead that the post office also appends while routing between its hubs.
(Aka your packet has to go from Post Office 1 -> Post Office 2, Post Office 2 -> Post Office 3, Post Office 3 -> Post Office 4, before it can go from Post Office 4 -> Your household).

QOS also accounts for these hub overheads in it's second meter.

--
WAN Overhead Explanation:
Now the issue is sometimes your ISP adds MORE overhead after the packet leaves your modem besides all the ones I just mentioned.

This extra overhead they add MAY or MAY NOT show up on your ISP's bandwidth meter. This really depends where they place it their own meter and how they configure it.

We need our 2nd bandwidth meter to accurately trigger BEFORE the ISP's bandwidth meter. This means we have to add this overhead, if present, into our QOS meter's reading/calculations.

The thing is we cannot physically see or read this overhead at our packets since it is stripped/added before it gets to us and after it leaves from us. This means it has to be entered manually.

--
WAN Overhead Issue:
As you saw from the examples, if you are sending many small messages these static overheads can be a significant chunk of the any bandwidth meter. If these overheads are present it can have the ISP meter trigger before our QOS meter. This will leave our QOS solution temporarily NOT EFFECTIVE while dealing with many small messages.

--

TL-DR

For QOS to work properly we have to take action BEFORE the isp meter overflows. This means our meter has to account for the "invisible to us" overhead IF the ISP meter accounts for it.

--

A possible test would be to watch bufferbloat during a speedtest compromised of many small packets compared to a typical one with the normally full packets. I do not have knowledge of any such test.

 

[RMerlin]

@RMerlin

Not related to his question, but looks like an HTML error on that page ('</option' in the next to last selection in the pulldown)

That pulldown is generated through add_option() so I don't see how that could be possible.

 

[john9527]

That pulldown is generated through add_option() so I don't see how that could be possible.

Because you copied/pasted a little too much ....(next to last index)

/* ATM, overhead, label */
var overhead_presets = [["0", "0", ""],
            ["0", "4", "Ethernet VLAN"],
            ["0", "18", "Cable (DOCSIS)"],
            ["0", "27", "PPPoE VDSL"],
            ["0", "19", "Bridged/IPoE VDSL"],
            ["1", "32", "RFC2684/RFC1483 Bridged LLC/Snap"],
            ["1", "32", "PPPoE VC/Mux</option"],
            ["1", "40", "PPPoE LLC/Snap"]];

 

[Netbug]

@FreshJR

Thank you for the very indepth explanation, will take multiple reads for it to sink in, really good info so thanks.

I am still confused though and not sure which option to choose from dropdown list and not sure if i can trust QoS statistics to determine how it sees VPN traffic, what confusing is how can the router identify the traffic when it's encrypted and going through vpn client 1 on router?

and as for Asus QoS, shocking to say the least my QoS statistics are so unlreliable they reset when they feel like it, yet they advertise QoS likes it's the best thing since sliced bread.

Cheers.

 

[FreshJR]

@FreshJR

Thank you for the very indepth explanation, will take multiple reads for it to sink in, really good info so thanks.

I am still confused though and not sure which option to choose from dropdown list and not sure if i can trust QoS statistics to determine how it sees VPN traffic, what confusing is how can the router identify the traffic when it's encrypted and going through vpn client 1 on router?

and as for Asus QoS, shocking to say the least my QoS statistics are so unlreliable they reset when they feel like it, yet they advertise QoS likes it's the best thing since sliced bread.

Cheers.

Whatever QOS statistics displays is EXACTALLY how your traffic is being identified by your router.

Once you "exceed" your bandwidth, QOS will start throwing out packets from the lowest catagory upwards.

QOS can identify a limited, but rather commonly encountered, ammount of HTTPS traffic. It should also ifentify the traffic before it is encrypted in your VPN container.

QOS restart can be trigger by multiple things but if you don't actively poke in the webUI settings a reset rarely happens.

 

[Netbug]

Thank you @FreshJR i understand now. Cheers.

 

[RMerlin]

Because you copied/pasted a little too much ....(next to last index)

/* ATM, overhead, label */
var overhead_presets = [["0", "0", ""],
            ["0", "4", "Ethernet VLAN"],
            ["0", "18", "Cable (DOCSIS)"],
            ["0", "27", "PPPoE VDSL"],
            ["0", "19", "Bridged/IPoE VDSL"],
            ["1", "32", "RFC2684/RFC1483 Bridged LLC/Snap"],
            ["1", "32", "PPPoE VC/Mux</option"],
            ["1", "40", "PPPoE LLC/Snap"]];

LOL, gotcha

 

[Netbug]

Because you copied/pasted a little too much ....(next to last index)

/* ATM, overhead, label */
var overhead_presets = [["0", "0", ""],
            ["0", "4", "Ethernet VLAN"],
            ["0", "18", "Cable (DOCSIS)"],
            ["0", "27", "PPPoE VDSL"],
            ["0", "19", "Bridged/IPoE VDSL"],
            ["1", "32", "RFC2684/RFC1483 Bridged LLC/Snap"],
            ["1", "32", "PPPoE VC/Mux</option"],
            ["1", "40", "PPPoE LLC/Snap"]];

hehe i used to do allot of web developing stopped doing it a few years ago, good catch @john9527

 

[sdmf74]

Sooo did we ever figure out what the best "wan packet overhead" setting is, ethernet vlan or cable docsis? Also what is the ATM tick box for? Thanks

 

[Therion87]

Sooo did we ever figure out what the best "wan packet overhead" setting is, ethernet vlan or cable docsis? Also what is the ATM tick box for? Thanks

It depends on your connection type. I have DOCSIS cable modem connection, so I use DOCSIS.

 

[FreshJR]

Sooo did we ever figure out what the best "wan packet overhead" setting is, ethernet vlan or cable docsis? Also what is the ATM tick box for? Thanks

Depends if your internet service provider is counting their encapsulation overhead (if present) against your rated speed.

If they do count the overhead, then the amount of bytes of overhead present per packet will vary determined by their encapsulation methods.

So, no, there is no best setting or definate answer on what setting to use, since it varies.

Fortunately a scenario where many small packets are transmitted (where the encapuslated overhead would be significant) is not a common scenario for most household connections.

In the end, don't worry about this setting. It's a marginal boost in accuracy under rare circumstances if you are able to determine what it is.

(Not impossible, just that there are no speed tests specifically created to determine this variable)

--

Side note: I do not think comcast counts their encapsulated overhead against your rated speeds.

 

[Vexira]

Hey

I setup my new RT-AC86U (previously used rt-68u), i got a media streaming box running over router vpn client 1, i've never used QoS before but know of some of it's problems, i don't want any complexity i just want to ensure i give priority to the streaming media box. Will it even work seeing vpn traffic is encrypted so won't know it's streaming?

First i went to Adaptive QoS > Bandwidth Monitor and dragged 'Highest' priority onto media box. Next went to Adaptive QoS > QoS. Where it says 'WAN packet overhead' I got the following options, i am on fibre connection and my isp does not require username/password (all automatic), what option do i choose? very confused.



I looked at this link from merlin https://github.com/RMerl/asuswrt-merlin/wiki/QoS-Queue-Disciplines and choose fq_codel as it seems to be the one recommended i think from the above link. But don't understand the 'WAN packet overhead' option.

Cheers.

I use VDSL ipoe setting, if you login with a username it's probably pppoe ATM settings is for ADSL

 

[sdmf74]

I have Mediacom so Im using the cable docsis setting & the fq_codel which I think is the best one, still curious about the ATM option though if anyone knows?

 

[FreshJR]

I have Mediacom so Im using the cable docsis setting & the fq_codel which I think is the best one, still curious about the ATM option though if anyone knows?

Doesn’t matter. Just an accuracy boost under uncommon corcumstances.

Greater gains are to be gained with tweaks to parameters elsewhere.