Community discussions

MikroTik App
 
MitchellPeixer
just joined
Topic Author
Posts: 3
Joined: Mon Jun 12, 2017 11:41 pm

PPPOE Server Uplink Consumption Difference

Tue Jun 13, 2017 3:10 pm

Hey guys,

I have a doubt while ago, consumption from the uplink interface are not the same with the interface that goes to the clients on pppoe server.

Images 01 ~ 03, printed from winbox

No OVPN, PPTP, L2TP, etc, services running on this servers, they are all pppoe server only. No strange traffic incoming or outcoming visible on torch, checked multiple times. This 3 servers are not all, we have more server with the same situation.
You do not have the required permissions to view the files attached to this post.
 
MitchellPeixer
just joined
Topic Author
Posts: 3
Joined: Mon Jun 12, 2017 11:41 pm

Re: PPPOE Server Uplink Consumption Difference

Tue Jun 13, 2017 5:18 pm

sorry for double post, but I had to add an extra image

print from nagios same host as image 01
You do not have the required permissions to view the files attached to this post.
 
savage
Forum Guru
Forum Guru
Posts: 1280
Joined: Mon Oct 18, 2004 12:07 am
Location: Cape Town, South Africa
Contact:

Re: PPPOE Server Uplink Consumption Difference

Tue Jun 13, 2017 5:53 pm

It's not out by a lot AFAIK.

Isn't this just normal packet overhead introduced by using PPPoE?

PS: Nice stats. Whilst not the biggest, that's one of the better graphs in terms of throughput that I've seen on a MT :D
 
User avatar
juliokato
Member Candidate
Member Candidate
Posts: 228
Joined: Mon Oct 26, 2015 4:27 pm
Location: Brazil

Re: PPPOE Server Uplink Consumption Difference

Tue Jun 13, 2017 6:12 pm

maybe overhead from pppoe header encapsulation?
 
MitchellPeixer
just joined
Topic Author
Posts: 3
Joined: Mon Jun 12, 2017 11:41 pm

Re: PPPOE Server Uplink Consumption Difference

Tue Jun 13, 2017 7:38 pm

It's not out by a lot AFAIK.

Isn't this just normal packet overhead introduced by using PPPoE?

PS: Nice stats. Whilst not the biggest, that's one of the better graphs in terms of throughput that I've seen on a MT :D
thanks!! :D

I have no idea... we see about 10% difference you think thats normal?
 
savage
Forum Guru
Forum Guru
Posts: 1280
Joined: Mon Oct 18, 2004 12:07 am
Location: Cape Town, South Africa
Contact:

Re: PPPOE Server Uplink Consumption Difference

Tue Jun 13, 2017 7:54 pm

I have no idea about the 10%... I think it could be. I'm fairly certain your issue is the additional encapsulation for PPPoE though. If memory serves me correctly, you're looking at 20 or 28 bytes per packet extra.

It really depends on your MTUs, whether there's other encapsulations evolved (VLANs, EoIP/VPLS / etc), average packet size your customers transmit / received, etc. It get's complicated.... Very complicated.

Take the amount of packets per second * 20 bytes per packet for PPPoE * 8 to convert the Bytes to Bits. Add those bits (bits/1024/1024 to make them Mbps) to your Interface Mbps, and see how close you get in terms of the difference between the two. If you're relatively (95 % odd) close to the same, then that's definitely your issue (again, assuming there's no other encapsulation involved, but it doesn't look like there is)...

IMHO, the difference isn't that significant that I personally would be concerned here. If you can post interface stats for both interfaces, showing Mbps and PPS, we could do some calculations, but PPS becomes more important here than Mbps. You should also see the PPS on the two interfaces will be far closer than the same on both interfaces, instead of the Mbps.

EDIT: Oh wait. I'm daft. I see the stats ARE there (PPS).
EDIT2: And in terms of PPS, queueing and packets being dropped by the queues could also affect this.