Since changing to a PPPOE ISP yesterday, my MX105 seems to be throttling speeds and I have no idea why. I was with Virgin Media (VM) who use DHCP public IP addresses but my new ISP (BT) uses PPPOE. I should be getting 900Mbps down and 110 up but I’m only seeing 350 down and 0.35 up.
When with VM, I had their router in modem mode and used the MX as the router and firewall. Everything was fine with VM and I got full speeds. When I moved to BT, I connected the MX direct to the ONT – the router doesn’t have a modem/bypass function – you just go direct to the ONT.
When I noticed the reduced speeds direct to the ONT, I unplugged the MX from the ONT, reconnected BT’s router and plugged in a laptop and ran some speed test, all of which showed full speeds (900/110).
Any ideas on what may be causing the reduced speeds through the MX?
Hopefully it's just a speed/duplex issue, we've seen this a couple times with our MX's that connect to CenturyLink or AT&T ONT's. We've had to go manually set the ports to 100/full or 1gbps/full, depending on what the carrier specifies.
Some thoughts of mine (I know nothing about BT ONT configuration):
Perhaps you are facing a speed/duplex mismatch. I'd try locking the config at 1000/full for a test.
DHCP has a 1500 byte MTU. PPPoE has a 1492 byte MTU. Perhaps you are experiencing an MTU squeeze. You can test this on windows by running: netsh interface ipv4 show subinterface Note the name of the interface being used for Internet traffic (it will have lots of traffic on it). Then temporarily change the MTU to something like 1300. netsh interface ipv4 set subinterface “Local Area Connection 2” mtu=1300 If that resolves it, you'll need to request Meraki support to lower the MTU for you.
Perhaps BT use a VLAN tag for the Internet service, and you are falling into some default service with lower performance by not using the same VLAN tag.