What is PPPoE MTU?
PPPoE MTU defines the maximum number of bytes that a PPPoE payload can have. This typically starts from IP layer in most cases. Below is what a typical PPPoE packet look like in terms of headers. Ethernet, then PPPoE then PPP followed by IP or IPv6 payload.
Is 1500 a good MTU?
The MTU (Maximum Transmission Unit) states how big a single packet can be. Generally speaking, when you are talking to devices on your own LAN the MTU will be around 1500 bytes and the internet runs almost universally on 1500 as well.
What is best MTU size?
28 bytes – IP header and ICMP headers. 1460 + 28 = 1488 is the optimum MTU Setting.
What is a good MTU size?
Add 28 to that number (IP/ICMP headers) to get the optimal MTU setting. For example, if the largest packet size from ping tests is 1462, add 28 to 1462 to get a total of 1490 which is the optimal MTU setting.
Is 1500 MTU bad?
It can really be anything below 1500 and it may work. Recommended that it is above 1400 still though. Having the maximum allowed MTU (1500) for Ethernet is used to allow for the most efficient packet transferring.
What MTU 1492?
The MTU size includes the data payload, any transport headers (such as TCP, UDP, GRE, RTP, or ICMP), and the IP header. It is generally recommended that the MTU for a WAN interface connected to a PPPoE DSL network be 1492. In fact, with auto MTU discovery, 1492 is discovered to be the maximum allowed MTU.
How big should the MTU and Mru be for PPP?
To prevent frequent fragmentation and reassembly for PPP packets over Ethernet, you can configure the maximum transmission unit (MTU) and MRU sizes for PPP subscribers. For PPPoE subscribers, the PPP MRU or PPP MTU size can be greater than 1492 bytes if the PPP-Max-Payload tag is received in the PPPoE Active Discovery Request (PADR) packets.
What does 58 bytes mean in PPP MTU?
58 bytes is the PPP overhead payload, which is calculated as the sum of the IP, UDP, L2TP, HDLC, and PPP header payloads. If the PPP MTU is configured using the mtu size statement, the PPP MTU is the lesser of the configured MTU and the (interface MTU – 58 bytes) value.
How is the MTU determined for a terminated PPPoE interface?
Junos OS determines the PPP MTU value for a terminated PPPoE interface based on the configured MTU, PPP lower-layer MTU, and the presence and value of the PPP-Max-Payload tag in the PADR packet. If the PPP lower-layer MTU falls below 1492 bytes, then the PPP MTU value is the lesser of the PPP lower-layer MTU and the configured MTU value.
What’s the maximum transmission unit ( MTU ) for Ethernet?
Standard Ethernet supports an MTU of 1500 bytes and Ethernet implementation supporting jumbo frames, allow for an MTU up to 9000 bytes. However, border protocols like PPPoE will reduce this. Path MTU Discovery exposes the difference between the MTU seen by Ethernet end-nodes and the Path MTU