I finally have a FTTC connection provided by UK ISP "SSE" so now I can post an update, which is really a request for help
With the ISP-supplied router/modem (a Technicolor TG589vac v2) everything works as expected and specifically I can send 1500-byte pings (i.e. 1500 IP packet size) with don't-fragment bit set successfully to/from my internet server. (I'll call these "full size pings"). So we know my ISP supports RFC4638 / baby-jumbos.
If I connect my hAP ac running RouterOS v6.43.4 to a TG589 LAN port then full-size pings still work OK.
If I set the TG589 into bridge mode, where the TG589 only handles the VDSL side (including VLAN tagging required for UK FTTC network) and the hAP does PPPoE then it partially works:
/interface pppoe-client add add-default-route=yes disabled=no interface=ether5 keepalive-timeout=disabled max-mru=1500 max-mtu=1500 name=SSE password=PASSWORD profile=pppoe-client-default use-peer-dns=yes user=USERNAME@ISP
13:59:13 pppoe,ppp,info SSE: initializing...
13:59:13 pppoe,ppp,info SSE: connecting...
13:59:13 pppoe,debug,packet ether5: sent PADI to FF:FF:FF:FF:FF:FF
13:59:13 pppoe,debug,packet session-id=0x0000
13:59:13 pppoe,debug,packet host-uniq=0x15b0001
13:59:13 pppoe,debug,packet service-name=
13:59:13 pppoe,debug,packet ppp-max-payload=1500
13:59:13 pppoe,debug,packet ether5: rcvd PADO from 2A:8A:1C:EC:7C:29
13:59:13 pppoe,debug,packet session-id=0x0000
13:59:13 pppoe,debug,packet ac-name=nge001.clc-re0
13:59:13 pppoe,debug,packet host-uniq=0x15b0001
13:59:13 pppoe,debug,packet ppp-max-payload=1500
13:59:13 pppoe,debug,packet service-name=
13:59:13 pppoe,debug,packet ac-cookie=1e 3f 7b 3c df 1e fe 44 ba 13 e9 34 fc 3e 7a 62
13:59:13 pppoe,debug,packet ether5: sent PADR to 2A:8A:1C:EC:7C:29
13:59:13 pppoe,debug,packet session-id=0x0000
13:59:13 pppoe,debug,packet host-uniq=0x15b0002
13:59:13 pppoe,debug,packet service-name=
13:59:13 pppoe,debug,packet ppp-max-payload=1500
13:59:13 pppoe,debug,packet ac-cookie=1e 3f 7b 3c df 1e fe 44 ba 13 e9 34 fc 3e 7a 62
13:59:13 pppoe,debug,packet ether5: rcvd PADS from 2A:8A:1C:EC:7C:29
13:59:13 pppoe,debug,packet session-id=0x015c
13:59:13 pppoe,debug,packet service-name=
13:59:13 pppoe,debug,packet host-uniq=0x15b0002
13:59:13 pppoe,debug,packet ppp-max-payload=1500
13:59:13 pppoe,debug,packet ac-name=nge001.clc-re0
13:59:13 pppoe,debug,packet ac-cookie=1e 3f 7b 3c df 1e fe 44 ba 13 e9 34 fc 3e 7a 62
... then LCP, IPIP, etc.
The hAP doesn't want to create a PPPoE session with 1500 MTU:
/interface print where type="pppoe-out"
Flags: D - dynamic, X - disabled, R - running, S - slave
# NAME TYPE ACTUAL-MTU L2MTU MAX-L2MTU MAC-ADDRESS
0 R SSE pppoe-out 1480
The hAP ethernet port connected to the TG589 has MTU set to 1512. I've tried setting various pppoe-client settings like "max-mtu" and "max-mru" to 1500. Even if I set the "pppoe-out" interface's MTU to 1500 it reverts back to 1480 after a few seconds.
Trying to offload more work onto the hAP just makes things worse for me.
With VLAN tagging turned off on the TG589 and a vlan interface created on the hAP then PPPoE from the hAP doesn't work at all:
/interface vlan add interface=ether5 mtu=1512 name=VDSL-vlan vlan-id=101 arp=disabled
/interface pppoe-client set [ find name=SSE ] interface=VDSL-vlan
I've no idea why because the "PADI" packets sent have the correct vlan ID but no "PADO" responses arrive:
19:17:12 pppoe,ppp,info SSE: initializing...
19:17:12 pppoe,ppp,info SSE: connecting...
19:17:12 pppoe,debug,packet VDSL-vlan: sent PADI to FF:FF:FF:FF:FF:FF
19:17:12 pppoe,debug,packet session-id=0x0000
19:17:12 pppoe,debug,packet host-uniq=0x13a0001
19:17:12 pppoe,debug,packet service-name=
19:17:12 pppoe,debug,packet ppp-max-payload=1500
19:17:13 pppoe,debug,packet VDSL-vlan: sent PADI to FF:FF:FF:FF:FF:FF
19:17:13 pppoe,debug,packet session-id=0x0000
19:17:13 pppoe,debug,packet host-uniq=0x13a0001
19:17:13 pppoe,debug,packet service-name=
19:17:13 pppoe,debug,packet ppp-max-payload=1500
The ideal final setup is with the Proscend 180-T in the SFP port in the hAP:
/interface ethernet set [ find default-name=sfp1 ] speed=1Gbps arp=disabled auto-negotiation=no mtu=1512
/interface vlan set [ find name=VDSL-vlan ] set interface=sfp1
As other people have said, setting speed=1Gbps and auto-negotiation=no gives the interface "running" state.
The green LED on the Proscend goes solid so I guess DSL synchronization is OK.
Again, no "PADO" responses arrive when I try PPPoE.
I do have a couple of RB260GS with also feature an SFP port so might try some tests using that.
So I guess I'm asking for feedback on:
- Known working/broken RouterOS devices, e.g. hAP ac works, hAP ac2 broken, RB260GS
- Known working/broken RouterOS versions, e.g. 6.43.4 works, 6.40.1 broken
- Confirmation/config examples of PPPoE with vlan tagging, particularly with 1500 MTU allowing full-size pings
Other related threads:
PPPoE MTU problem
PPPoE connection to UK BT ADSL, MTU with RFC 4638 which mentions RouterOS RFC4638 support since 6.33!
PPPoE RFC4638 problem. Not seeing 1500 MTU on pppoe-client?
More investigation into Mikrotik PPPoE negotiated MTUs