FTTH download speed and VLAN

Hi all,

I living in Spain, I changed my internet provider and I have some problems on download speed. I need your help to understand why.

My environment:

Router: rb951g
Provider: Jazztel
Connection: IPoE with VLAN 20
Speed: 1Gb/s

My previous provider (600Gb/s) had the same technology without the vlan and everything works correctly. I can reach the max speed in upload and download.

Currently I can reach the max upload speed but I have problem in download in TCP. The remote iperf3 server is on cloud with a 4Gb/s nic without any restriction of bandwidth egress/ingress.

Tested with a linux and mac os computer with ethernet cable.

TCP

Upload 930 Mb/s
iperf3 -c 1 public_external_IP -P 10 -t 15

Download 430 Mb/s
iperf3 -c 1 public_external_IP -P 10 -t 15 -R

UDP

Upload 930 Mb/s
iperf3 -c public_external_IP -u -b 2G

Download 930 Mb/s
iperf3 -c public_external_IP -u -R -b 2G

I try these commands with 2 different router. My old Mikrotik and the router provided by the provider. Same results more or less.

If I test the connection with my laptop connected with ethernet cable, I can reach 700/800Mb/s on fast.com… a little less with the ockla speed test.
In wifi (near the AP) I can’t reach more than 350Mb/s in download with fast.com. My wifi is capable to reach 600Mb/s (Unifi 6 lite). Same result with the WIFI integrated in the router provided by Jazztel.

Jazztel declare that on ONT there is 1Gb/s. (And I can reach it with UDP test…)

The problem on my Mikrotik could it be related to the vlan and my old device could not provide more performance?
The problem on the router provided by Jazztell could be because it is a shit device?

Could I have your advice?
Thanks
Marco

If you’re using RB951G in routing mode (as opposed to switching mode), then yes, it’s too slow for your internet link. RB951G can realistically route with speeds up to around 300Mbps (give or take, depends on firewall configuration).
In switching mode it should be able to handle wirespeed if properly configured (e.g. VLANs configured under /interface ethernet switch).

For more concrete advice we have to see full config (execute /export hide-sensitive file=anynameyouwish in terminal window, fetch file off device, open it using text editor, obfuscate remaining sensitive data such as serial number or public IP address, and post it inside [__code] [/code] block).

Thank you for your answer.

The funny fact is that my old provider with the same configuration (withou vlan configured on eth1 …my WAN port) I can reach, without problems, 600Mb/s in download with cable or wifi. Now only with the cable, in WIFI I’m stuck on 320Mb/s and I don’t understand why… If the router can manage this speed, why can manage it with cable and not with the WIFI? And why I can reach 600/700Mb/s only with fast.com test and not with iperf3?

As I wrote: post config and we might figure out why such a speed drop with new ISP.

Hi,

this is my conf.
configsensitive.rsc (28.2 KB)

could be realated to the vlan configured on eth1 interface? Is it possible configure it on eth1 port into the switch chip?

thanks

First of all, the VLAN setup (the part with vlan101 interface) is made in kind-of legacy way … so it may be working but it’s weird. It should not affect the WAN throughput though.

But no, you can’t really speed up VLAN tagging on your WAN interface (ether1). The thing is this: pppoe-client works with untagged frames only. Therefore you need vlan interface (vlan20) to do the untagging (when passing from anchor interface towards pppoe-client) and tagging (when passing from ppoe-client towards anchoring interface) - in this case “anchoring interface” is ether1. And traffic over ether1 has to be tagged because your ISP requires that.
The switch port which could do the tagging instead of vlan interface is switch1-cpu interface … but that would affect all traffic passing between switch chip and router’s CPU, including LAN traffic to/from router … and that’s probably not what you’d want.

The only scenario where switch chip could help you would be if you’d have two ethernet prots bridged and one would have to carry tagged frames and the other one untagged … switch chip could add tags when frames would be passing from untagged towards taged port and strip tags when frames would be passing in the opposite direction. When it comes to interaction of router with any of VLANs, it boils down to what I described in previous paragraph.

Once (when vlan-aware bridge came to ROS with v6.42) I did some benchmark tests with my RB951G, used as VLAN switch. When switch chip did the tagging/untagging, intra-VLAN traffic passed device at wire speed (1Gbps) without any effect on CPU. When I reconfigured it to use VLAN-aware bridge (so CPU was doing tagging/untagging, albeit ROS code doing it was probably different than in your case), the througput peaked at around 0.5Gbps and CPU utilization was hitting 100%. My benchmark is not a good example of how device performs in your case (in my case it was flip from all HW-offloaded operation to fully CPU-bound operation, in your case it is simply adding a single operation), it only indicates that CPU in this device can not handle even most trivial tasks (e.g. adding/stripping VLAN header) at wirespeed.