Kol wrote:Hi Brzxc, I had the same issue, fixed by increasing the MTU of the ATM interface:
set interfaces at-1/0/0 mtu 1540I believe the MTU setting under a physical interface on Juniper is the total, inclusive of the layer 2 headers, whereas MTU under a family stanza is not including layer 2 overhead.
I know this is a super old thread, but it still manages to occur. Is there any definitive reason why this is the case? I can indeed also confirm that using Internode PPPoE I had to have MTU 1540 set or i just didnt get any auth. The ppp traceoptions were absolutely no help.
I would have thought that leaving the MTU out would just let the interface determine its own (correctly?)
At the moment mine is showing (with the at-1/0/0 interface set to a MTU of 1540)
Physical interface: at-1/0/0, Enabled, Physical link is Up Interface index: 148, SNMP ifIndex: 532, Generation: 152 Link-level type: Ethernet-over-ATM, MTU: 1524, Clocking: Internal, ADSL mode, Speed: ADSL2+, Loopback: None
vs
Physical interface: at-1/0/0, Enabled, Physical link is Up Interface index: 148, SNMP ifIndex: 532, Generation: 152 Link-level type: Ethernet-over-ATM, MTU: 1514, Clocking: Internal, ADSL mode, Speed: ADSL2+, Loopback: None
when it doesnt.
I can see where it gets the default from
in 1514, but just trying to work out why it has to be 1524 to actually work (setting it to 1540 just defaults back to 1524 anyway, so may as well set to the exact value its looking for)
would really appreciate some info here.... I have logged same question with JTAC for their thoughts too