Yes, it says so in RFC 1122. Microsoft sends 576-byte packets when it does IKEv1 fragmentation.
Still, I don't think you're going to find on the modern Internet any networks that aren't usable by IPv6. So I think we should be pretty safe in adoption IPv6's minimum of 1280 Yoav On Oct 17, 2013, at 9:34 PM, Mike Sullenberger (mls) <[email protected]> wrote: > As I remember it IPv4 has a minimum packet size of 576 that won't (or at > least shouldn't be) fragmented by IP. > > Mike. > > > Mike Sullenberger, DSE > [email protected] .:|:.:|:. > Customer Advocacy CISCO > > > >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On Behalf >> Of Valery Smyslov >> Sent: Wednesday, October 09, 2013 10:34 PM >> To: Paul Wouters >> Cc: [email protected] >> Subject: Re: [IPsec] I-D Action: draft-ietf-ipsecme-ikev2-fragmentation- >> 03.txt >> >>>> I also think that PMTU discovery isn't very useful for IKE. >>>> That's why it is MAY. >>> >>> That does not help implementors who still have to implement the MAY's. >>> if even you as a document author does not think it is very useful, >>> then I think it should just not be in the document. >> >> Sorry, I wasn't very clear. By "isn't very useful" I meant that it is not >> useful >> for the usual PMTU discovery goal in TCP - to find _maximum_ IP datagram >> size that is not fragmented by IP level. In IKE its the goal is different - >> to find >> _some_reasonable_ IP datagram size that is not fragmented by IP. >> >> If we have the size that is guaranteed to not be fragmented, no PMTU >> discovery will be needed. As far as I understand, for IPv6 it is 1280 bytes. >> But >> as far as I know, there's no such value for IPv4. >> If we mandate (or recommend) using really small value e.g. 128 bytes, than >> the performance will suffer badly, so it is not a good option. >> I'm especially worrying about network I'm not familiar with - mobile >> networks or other constrained environments. >> It would be great if some experts in such networks could clarify this. >> >> _______________________________________________ >> IPsec mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/ipsec > _______________________________________________ > IPsec mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/ipsec _______________________________________________ IPsec mailing list [email protected] https://www.ietf.org/mailman/listinfo/ipsec
