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pe1chl
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Re: Mikrotik VDSL / DSL Modem?

Tue Nov 13, 2018 7:34 pm

Using 1500-byte MTU with PPPoE is only possible when the ISP and the modem supports RFC4638.
When one of them doesn't, the router reverts to the safe MTU of 1480. However when manually configuring it should be
possible to get MTU 1492, when the modem at least supports VLAN tagging. When not, maybe 1488.
You cannot force the matter by setting higher values without the support. It will not work and/or it will crash the modem.
(in case of an AVM FritzBox in bridge mode it does that)
 
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dohmniq
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Re: Mikrotik VDSL / DSL Modem?

Tue Nov 13, 2018 8:41 pm

The ISP definitely supports RFC4638 as using the TG589 for VDSL+PPPoE allows non-fragmented 1500-byte pings. (I say "ISP" but it's probably true for any ISP using OpenReach network).
RouterOS allegedly has RFC4638 support since version 6.33, albeit with some bug-fixes since then!

But you have given me an idea to test:

Maybe with the TG589 in "bridge mode", doing only VDSL (and VLAN tagging) but not PPPoE, the TG589's ethernet port's MTU is only 1500?
This could mean that although everything is set up OK in RouterOS, the PPPoE negotiation fails somehow.
Should be easy enough to test next time I have some spare hours to rearrange everything again.
 
rendrag
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Re: Mikrotik VDSL / DSL Modem?

Tue Nov 13, 2018 9:14 pm

Couple of thoughts..

1) Re the TG589: make sure you have also increased the MTU on the TG589, or you're simply not going to be able to use packets larger than 1500 with it. You can't JUST increase packet size on the Mikrotik side.. :)

2) Whoever said turning off autonegotiate was the way to go with the SFP's gave you a bum steer. I've never had this work. The only way I can get the 180-T SFP's to work on my CRS-109's, is to power the CRS109 on, wait for it to boot, THEN insert the 180-T. If the 180T is installed when the Mikrotik boots, it will never pass traffic even after the sync light goes solid green.

Cheers,

DG
 
pe1chl
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Re: Mikrotik VDSL / DSL Modem?

Tue Nov 13, 2018 10:58 pm

To have MTU of 1500 on PPPoE you need to have MTU at least 1512 on ethernet (or in case VLAN tags are not counted at least 1508).
When it is not possible to raise MTU on ethernet (both on router and modem) to this value the RFC4638 protocol will detect this and the MTU of the PPPoE link will be lower.
I have had working MTU 1500 connection both with the SFP discussed in this thread and with Draytek Vigor 130 external VDSL2 modem which supports RFC4638.

Apparently your modem does not support RFC4638 and it will fail.
You are lucky that it just lowers the MTU (the RFC4638 does a ping of a large packet and it does not receive the reply), when doing the same with an AVM Fritzbox the large
packets just crash the modem and it will reboot and re-train. Likely some buffer overflow somewhere.
 
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dohmniq
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Re: Mikrotik VDSL / DSL Modem?

Wed Nov 14, 2018 2:37 pm

Update: online!

Probably the most critical aspect was this gem by rendrag:
2) Whoever said turning off autonegotiate was the way to go with the SFP's gave you a bum steer. I've never had this work. The only way I can get the 180-T SFP's to work on my CRS-109's, is to power the CRS109 on, wait for it to boot, THEN insert the 180-T. If the 180T is installed when the Mikrotik boots, it will never pass traffic even after the sync light goes solid green.

If you turn OFF auto-negotiate then you will see the "R" running flag but no packets are ever received from the SFP interface.
If you turn ON auto-negotiate, and maybe set advertise=1000M-full as needed, then the next time you insert the modem into the SFP cage it will work!
It's not enough to set advertise and auto-negotiate=on with the device already in place, it needs to be re-inserted after these settings have been changed.
Also, with my hAP ac running 6.43.4 the SFP interface will not work after a reboot, it will again need to be re-inserted.
(I'm about to raise a support ticket for that with supouts)

On the PPPoE front, I set the SFP interface's MTU to 1598 (easily enough for PPPoE + VLAN overhead) and the vlan's MTU to 1560 (easily enough for PPPoE overhead).
The other pppoe-client settings were max-mtu=1500 max-mru=1500, leaving mrru=disabled.

Really glad I don't have to use the locked-down TG589 as a glorified modem.
 
pe1chl
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Re: Mikrotik VDSL / DSL Modem?

Wed Nov 14, 2018 3:55 pm

If you turn OFF auto-negotiate then you will see the "R" running flag but no packets are ever received from the SFP interface.
If you turn ON auto-negotiate, and maybe set advertise=1000M-full as needed, then the next time you insert the modem into the SFP cage it will work!
O that is interesting, that must be some bug/feature introduced in RouterOS recently!
When I first received my SFP, it worked fine with auto-negotiate off. I had 1500 byte MTU all working (same as how you wrote above) and the only problem was I did not get my expected line speed and there is no way to monitor why.
Recently I tried the SFP again and same problem as you write: nothing received. I feared I had damaged the SFP somehow and put it aside.
Now I will try again with what you describe.
 
rendrag
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Re: Mikrotik VDSL / DSL Modem?

Thu Nov 15, 2018 12:37 am

O that is interesting, that must be some bug/feature introduced in RouterOS recently!
When I first received my SFP, it worked fine with auto-negotiate off. I had 1500 byte MTU all working (same as how you wrote above) and the only problem was I did not get my expected line speed and there is no way to monitor why.
Recently I tried the SFP again and same problem as you write: nothing received. I feared I had damaged the SFP somehow and put it aside.
Now I will try again with what you describe.
Oh that could be - You had yours quite some time before I finally got mine, and I think I was on a newer RouterOS version than you at the time, and didn't want to roll back to test it.

it's quite annoying though, as when the SFP does finally stop working (it was every 6 weeks like clockwork for a while, but it's just gone 3 months without a failure until last week..), it means I have to power cycle the CRS109 it lives in, and remove the SFP while it gets power cycled, which means I have to be at home to do it, or talk the missus through it..
 
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Re: Mikrotik VDSL / DSL Modem?

Mon Feb 18, 2019 12:56 pm

If you turn OFF auto-negotiate then you will see the "R" running flag but no packets are ever received from the SFP interface.
If you turn ON auto-negotiate, and maybe set advertise=1000M-full as needed, then the next time you insert the modem into the SFP cage it will work!
O that is interesting, that must be some bug/feature introduced in RouterOS recently!
When I first received my SFP, it worked fine with auto-negotiate off. I had 1500 byte MTU all working (same as how you wrote above) and the only problem was I did not get my expected line speed and there is no way to monitor why.
Recently I tried the SFP again and same problem as you write: nothing received. I feared I had damaged the SFP somehow and put it aside.
Now I will try again with what you describe.
any news from mikrotik support?
Last edited by timothy77 on Mon Feb 18, 2019 5:53 pm, edited 1 time in total.
 
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dohmniq
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Re: Mikrotik VDSL / DSL Modem?

Mon Feb 18, 2019 4:40 pm

No reply. I can't even find any "support tickets" section when I log into my Mikrotik account. I guess it's not a priority for them.
On the bright side, uptime now at 13 weeks although I did have to disable/re-enable the pppoe-client entry after being away for a week but everything SFP-wise seems stable.
 
yacsap
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Re: Mikrotik VDSL / DSL Modem?

Wed May 01, 2019 12:17 am

Hi everyone,

these are the xDSL ATM settings of the modems mentioned above:
Image
Hi Milotop,

How/where can we configure the VPI setting?

A screenshot from your Inbox with VPI setting would be helpful.

Many thanks,
b.L
[ IMikroTik ] >
 
pe1chl
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Re: Mikrotik VDSL / DSL Modem?

Wed May 01, 2019 10:13 am

You cannot configure it. You can only select a VPI/VCI setting from the above list.
You do that by accessing the link via a VLAN as in the last column of the table.
So to use VPI/VCI setting 8/36 you use VLAN 7.

VPI/VCI setting not in the table? -> you cannot use this modem.
 
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Re: Mikrotik VDSL / DSL Modem?

Wed May 22, 2019 2:44 am

You cannot configure it. You can only select a VPI/VCI setting from the above list.
You do that by accessing the link via a VLAN as in the last column of the table.
So to use VPI/VCI setting 8/36 you use VLAN 7.

VPI/VCI setting not in the table? -> you cannot use this modem.
I just used VLAN10 as the ISP has recommended me and it works like charm.
[ IMikroTik ] >
 
pe1chl
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Re: Mikrotik VDSL / DSL Modem?

Wed May 22, 2019 10:51 am

I just used VLAN10 as the ISP has recommended me and it works like charm.
So it likely is VDSL, not ADSL, so you do not have ATM and no VPI/VCI settings.
In that case this limitation does not occur.

Do you get the expected speed (same as a ISP supplied modem)?
It still is unfortunate that MikroTik does not add the display of the line parameters for these modems...
 
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Re: Mikrotik VDSL / DSL Modem?

Tue Jun 18, 2019 6:33 pm

I can recommend https://www.mikrotik-shop.de/Interfaces ... :2192.html

I got mine 2 days ago and it works great on a O2 VDSL 50/10 MBit connection.
But it does not work with Dt. Telekom (T-COM) VDSL connections. That should change during 2018.

With my O2 VDSL I got 49.7 MBit down and 9.4 MBit uplink.

1. After inserting the module, it was directly recognized (sfp1).
2. I switched off autonegotiation on the sfp device.
3. I created VLAN7 (vlan7) and connected it to the sfp device(sfp1).
4. Then I created a PPPoE Client, connected it to Interface vlan7 and configured the dial-out setting with my O2 credentials.
Then finally I switched off my FB. :)

That's it ... Really great stuff!
Step 5: /Interfaces/Interface List => WAN => Switch to Interface SFP.

Can confirm. T-Online. Works great, but slower than a Draytek Vigor 130.
VDSL 100/50:
Vigor 130: 91/28
SFP: 75/25.

Thank you all for your inputs :)
 
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Re: Mikrotik VDSL / DSL Modem?

Wed Oct 09, 2019 6:20 pm

Anybody tested any of those SFP modem in north america?

Rock

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