ipv4 MTU

[rickr4433]

What is the maximum possible packet size that can be sent over ip v4, (without regard to fragmentation.)
Thanks

 

[Morsing]

Do you mean packet or frame size?? Frames can't be fragmented, packets can. The frame size is 1500bytes.

packet size (windows) has nothing to do with the network (I think) only the IP stack of the recieving host.

Cheers

Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support

 

[jimbopalmer]

There are various nonstandard Jumbo Frames implementations. Prior to 802.1Q and 802.1p 1514 was as large as I saw in the standard, now a tagged frame can be 1518.

I tried to remain child-like, all I acheived was childish.

 

[gunthnp]

ethernet 1500 bytes 1518 with vlan info

gunthnp
If you like my tip please mark it.

 

[Comstocb]

They are generally correct but I have to disagree with the last few posts a little (I suspect they omitted the CRC's 4 bytes) and say when the internet is involved, you are restricted to a frame size of 1518 bytes (1500 byte packet size plus source/dest. MAC addresses, ethertype and CRC making it a 1518 byte frame). If 802.1q tagging is involved, it adds an additional 4 bytes to max out the packet size at 1522 bytes. Tagging never reaches the internet however as it takes both sides having tagging enabled for tagging to work and I don't imagine ISP will be enabling tagging on their equipment (could be wrong, I have never asked them).

Now, if you control the environment (meaning its a LAN and you can configure the switching/routing equipment), larger sizes are possible. My Extreme gear can support a size of 9216 (called Jumbo frames in Extreme slang).

Hope this helps

Brian