Feb 26, 2008
Sophos XG Firewall: How to set the MTU on a PPPoE interface KB-000036093 02 13, 2020 02 13, 2020 With the MTU on PPPoE connections set to 1452 the overhead per frame is reduced by 0.44%. This translates into a faster Internet connection. On a standard T1 at 1.544 Mbps, this means an increase of about 10 kbps. NOTE: MTU may differ per provider. • The built in PPPoE client for Windows XP uses an MTU that is set to 1480. For more information please reference this XP MTU article. This only applies if you are running the built in XP PPPoE client! Finding the Correct MTU MTU/MRU When a PPPoE-speaking DSL modem sends or receives Ethernet frames containing PPP + PPPoE payload across the Ethernet link to a router (or PPPoE-speaking single PC), PPP + PPPoE contributes an additional overhead of 8 bytes = 2 (PPP) + 6 (PPPoE) included within the payload of each Ethernet frame. In computer networking, the maximum transmission unit (MTU) is the size of the largest protocol data unit (PDU) that can be communicated in a single network layer transaction. The MTU relates to, but is not identical to the maximum frame size that can be transported on the data link layer, e.g. Ethernet frame. MTU Issues¶ Issues with upload speed frequently end up being issues with the MTU. If the MTU on pfSense® software (default 1500), is higher than the MTU of the upstream link, it can result in packets being fragmented, lost, or otherwise mishandled. Setting MSS clamping on the WANs or changing the MTU of the interface may help. MTU. Typically, the largest Ethernet frame that can be transmitted without fragmentation is 1500 bytes. PPPoE adds another 6 bytes of overhead and PPP field adds two more bytes, leaving 1492 bytes for IP datagram. Therefore max PPPoE MRU and MTU values must not be larger than 1492.
PPPoE server sends Echo-Request packets to the client to determine the state of the session, otherwise, the server will not be able to determine that session is terminated in cases when a client terminates session without sending Terminate-Request packet.. MTU. Typically, the largest Ethernet frame that can be transmitted without fragmentation is 1500 bytes.
It's fairly well documented that I need to set my MTU to 1452 (NTT Flet's, Japan) because of some q-in-q stuff NTT is doing on the transit to their pppoe concentrators. At my previous setup with edgerouter poe, the mtu was easily set and internets was fast (mss clamping doesn't seem to do anything), and with the UDM pro I can't find it anywhere MTU - AAISP Support Site
Maximum MTU for PPPOE - Plusnet Community
I understant that the usual maxium mtu on a PPPoE connection is 1492 (1500 minus the 8 bits that PPPoE is adding). but that said, Bell allows us to use 1500 (1500+8). Some users did this with their own pfsense "router" and this helps to get a little bit more throuput. So why is this EA9500 router limited to 1492 when a PPPoE is used? PPPoE on WAN link for Centurylink gigabit service