Spark VDSL + pppoe MTU

Forums › Spark New Zealand (including Skinny and BigPipe) › Spark VDSL + pppoe MTU

dfnt

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#212744 10-Apr-2017 16:47

Searching back I've seen a couple of posts regarding Spark supporting RFC 4638 on VDSL, however when I try it partially works but I can't browse certain sites (I assume because of MTU size issues) www.nzherald.co.nz and www.gpforums.co.nz to name a couple.

I'm setting MTU to 1508 on the ethernet interface connected to the modem, and 1500 on the pppoe interface and it connects fine, the same issue occurs on either ERL or pfsense.

Do Spark support this on VDSL or just UFB?

cbrpilot

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#1760359 10-Apr-2017 17:00

Yes, Spark supports a 1500 byte MTU on VDSL.

Just checked one of our BNGs, and we do have quite a few customers online negotiating an 1500 byte MTU.

Some modems support it, others do not.

My views are my own, and may not necessarily represent those of my employer.

dfnt

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#1760361 10-Apr-2017 17:10

I'm just bridging the HG630b to either an Edgerouter or pfsense box, whenever I try 1500 MTU I can't get to both afformentioned sites

sbiddle

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#1760376 10-Apr-2017 18:09

I'm pretty sure they only support 1500 bytes max in bridge mode so if you're desperate for 1500 you'll need to buy a better modem... Or just settle for 1492.

dfnt

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#1760381 10-Apr-2017 18:42

It is bridged, same thing happens with a zyxel p-870h-51a v2 as well

Not desperate, was just curious as to why it wasn't working

hio77

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#1760385 10-Apr-2017 18:56

sbiddle:

I'm pretty sure they only support 1500 bytes max in bridge mode so if you're desperate for 1500 you'll need to buy a better modem... Or just settle for 1492.

Interesting point.. I must test this on my device..

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

hio77

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#1760393 10-Apr-2017 19:22

hio77:

sbiddle:

I'm pretty sure they only support 1500 bytes max in bridge mode so if you're desperate for 1500 you'll need to buy a better modem... Or just settle for 1492.

Interesting point.. I must test this on my device..

So just tested this on my setup.

[2.1.4-RELEASE][admin@edge-router.home.baird.io]/root(1): ifconfig pppoe1
pppoe1: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> metric 0 mtu 1492
inet 122.57.xxx.xxx --> 125.238..xxx.xxx netmask 0xffffffff
inet6 fe80::20c:29ff:fee7:c677%pppoe1 prefixlen 64 scopeid 0x10
nd6 options=3<PERFORMNUD,ACCEPT_RTADV>

[2.1.4-RELEASE][admin@edge-router.home.baird.io]/root(2):
Message from syslogd@edge-router at Apr 10 19:04:24 ...
edge-router php: /index.php: Successful login for user 'admin' from: 10.3.57.13

[2.1.4-RELEASE][admin@edge-router.home.baird.io]/root(2): ifconfig pppoe1
pppoe1: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> metric 0 mtu 1500
inet 122.57.xxx.xxx --> 125.238.xxx.xxx netmask 0xffffffff
inet6 fe80::20c:29ff:fee7:c677%pppoe1 prefixlen 64 scopeid 0x10
nd6 options=3<PERFORMNUD,ACCEPT_RTADV>

My bridging modem is a NF4V in this case.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

dfnt

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#1760467 10-Apr-2017 21:43

I get that too, but doesn't seem to fully work

igb0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1508
options=6400bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,VLAN_HWTSO,RXCSUM_IPV6,TXCSUM_IPV6>
ether 0c:c4:7a:31:88:a0
inet6 fe80::ec4:7aff:fe31:88a0%igb0 prefixlen 64 scopeid 0x1
nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
media: Ethernet autoselect (100baseTX <full-duplex>)
status: active

pppoe0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> metric 0 mtu 1500
inet 219.88.164.197 --> 125.239.241.1 netmask 0xffffffff
inet6 fe80::ec4:7aff:fe31:88a0%pppoe0 prefixlen 64 scopeid 0xa
nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>

But yeah, doesn't seem to fully work

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BarTender

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#1764479 14-Apr-2017 17:56

An MTU of 1508 should work fine on all access types so you should be able to do a 1500 byte Ethernet frame as long as your router supports it. The only access that it may not work on is BUBA. But I know it works on UFB and VDSL just fine. But if you're at all concerned set a MTU of 1492 as that should work no matter what.

dfnt

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#1764499 14-Apr-2017 19:36

Whether I use the edgerouter, pfsense, h630b or zyzel I can't use an MTU of 1508 as sites like nzherald, gpforums etc stop working