MTU setting will it affect profile

[pctech]

Now I know that MTU only affects outbound packets but wonder if this has any effect on the BT line profile as its set to 1458 at the min and wondering if I'll get any benefit from setting it to 1500?

[Rik]

Try it and see, Mitch. I use 1500, it produced the best results for me.

[esh]

MTU! This takes me back to the days of optimising 28k modems where an extra 0.2K made everything seem zippy. Does it really affect much anymore what with low latencies being the norm on digital lines? How much difference did it make for you Rik, did you make any measurements? Next it will be parity bits and software flow control! Serial cables! Argh!

[Rik]

Happy days. For me, it had no effect on pings, but I was able to improve throughput slightly by having the larger packets.

[Gary]

!500 worked well for me as well, seems to be the best setting after experimenting.

[nowster]

MTU can have a slight impact on throughput, due to the PPP/L2TP encapsulation and ATM framing. I seem to remember that making the MTU+PPP overhead a whole number of ATM frames can raise throughput a fraction.

The difference between MTU of 1458 and 1500 isn't going to be that great until you get much above 10Mbps.

If Path MTU Discovery isn't working at any point along the network chain to a remote server, you may need a working 1500byte MTU. PMTU can be disrupted by incorrectly configured routers/firewalls/load balancers which don't pass back the correct ICMP packets.

[Rik]

Thanks for that explanation, I knew it had an effect for me, but not why.