RFC4638? Baby jumbo frames for PPPoE connections (MTU 1508)

[martin42]

Hi,

Does 2.2-RELEASE support baby jumbo frames for PPPoE?  That would be great for FTTC connections in the UK.

Many thanks!

• Martin.

[jimp]

I believe so, there was at least one, possible more, forum thread about it in the 2.2 development board.

[pf3000]

Any idea how this might work on pfSense? Simply setting the WAN MTU to 1508 doesn't work for me.

My GPON internet does RFC 4638. I could connect and ping 1472 bytes using Openwrt BB.

[pf3000]

I set the following:
WAN MTU to 1500
interfaces>PPPs>pppoe0> MTU = 1500 and MRU =1500

Result: everything looks ok from the outside except ping.

[2.2-RELEASE][root@pfSense.playgroup]/root: ifconfig pppoe0
pppoe0: flags=88d1 <up,pointopoint,running,noarp,simplex,multicast>metric 0 mtu 1500
        inet 92.98.85.45 --> 31.215.64.1 netmask 0xffffffff
        inet6 fe80::20c:29ff:feb2:e4ab%pppoe0 prefixlen 64 scopeid 0x7
        nd6 options=21 <performnud,auto_linklocal>[2.2-RELEASE][root@pfSense.playgroup]/root: ifconfig vmx0
vmx0: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500
        options=60079b <rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,tso4,tso6,lro,rxcsum_ipv6,txcsum_ipv6>ether 00:0c:29:b2:e4:ab
        inet6 fe80::20c:29ff:feb2:e4ab%vmx0 prefixlen 64 scopeid 0x1
        nd6 options=21 <performnud,auto_linklocal>media: Ethernet autoselect
        status: active
[2.2-RELEASE][root@pfSense.playgroup]/root: route get 8.8.8.8
   route to: google-public-dns-a.google.com
destination: default
       mask: default
    gateway: 31.215.64.1
        fib: 0
  interface: pppoe0
      flags: <up,gateway,done,static>
 recvpipe  sendpipe  ssthresh  rtt,msec    mtu        weight    expire
       0         0         0         0      1500         1         0
[2.2-RELEASE][root@pfSense.playgroup]/root: ping -c 4 -s 1472 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 1472 data bytes
^C
--- 8.8.8.8 ping statistics ---
4 packets transmitted, 0 packets received, 100.0% packet loss
[2.2-RELEASE][root@pfSense.playgroup]/root: ping -c 4 -s 1462 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 1462 data bytes
1470 bytes from 8.8.8.8: icmp_seq=0 ttl=50 time=119.920 ms
1470 bytes from 8.8.8.8: icmp_seq=1 ttl=50 time=116.631 ms
1470 bytes from 8.8.8.8: icmp_seq=2 ttl=50 time=116.487 ms
1470 bytes from 8.8.8.8: icmp_seq=3 ttl=50 time=116.757 ms

--- 8.8.8.8 ping statistics ---
4 packets transmitted, 4 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 116.487/117.449/119.920/1.430 ms</up,gateway,done,static></performnud,auto_linklocal></rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,tso4,tso6,lro,rxcsum_ipv6,txcsum_ipv6></up,broadcast,running,simplex,multicast></performnud,auto_linklocal></up,pointopoint,running,noarp,simplex,multicast>

[pf3000]

I suppose PPPoE in pfSense/FreeBSD is maximum of 1492

Feb 6 10:36:14	ppp: mpd_wan.conf:31: Error in 'set link mtu 1500': max MTU on type "pppoe" links is 1492
Feb 6 10:36:14	ppp: mpd_wan.conf:32: Error in 'set link mru 1500': max MRU on type "pppoe" links is 1492
Feb 6 10:36:14	ppp: [wan_link0] Link: OPEN event
Feb 6 10:36:14	ppp: [wan_link0] LCP: Open event

More info
Baby jumbo frames (MTU 1508) for PPPoe connections?

[nietzowietzo]

Anyone got it working already? Just like in the UK many Fiber optic providers in the Netherlands use PPPoE and support RFC4638. So it would be great if we can get it working.

[pf3000]

I'm prepared to offer a bounty to anybody who makes this happen. Bounty thread started for those who would like to contribute
RFC 4638 (PPPoE 1508 MTU) - let's pitch in