> On Apr 10, 2015, at 3:49 PM, Larry Kreeger (kreeger) <[email protected]> > wrote: > > I thought Path MTU discovery was used to set the MSS in the TCP stack. I > just wasn't sure if it worked the same way for UDP. >
Since, as you know, UDP has no MSS and no connection, the packetization size state is maintained by the application on top of UDP, or suffer IP-level fragmentation. See e.g, first para of https://tools.ietf.org/html/rfc1191#section-6.1 <https://tools.ietf.org/html/rfc1191#section-6.1> Thanks, ― Carlos. > - Larry > > From: Anoop Ghanwani <[email protected] <mailto:[email protected]>> > Date: Friday, April 10, 2015 12:10 PM > To: Larry Kreeger <[email protected] <mailto:[email protected]>> > Cc: Lizhong Jin <[email protected] <mailto:[email protected]>>, Lucy yong > <[email protected] <mailto:[email protected]>>, Erik Nordmark > <[email protected] <mailto:[email protected]>>, "[email protected] > <mailto:[email protected]>" <[email protected] <mailto:[email protected]>> > Subject: Re: [nvo3] Encapsulation considerations > > Even for TCP it depends on what the MSS is. > > Anoop > > On Fri, Apr 10, 2015 at 11:55 AM, Larry Kreeger (kreeger) <[email protected] > <mailto:[email protected]>> wrote: >> On 4/9/15 7:22 PM, "Lizhong Jin" <[email protected] >> <mailto:[email protected]>> wrote: >> >> >>-----Original Message----- >> >>From: Lucy yong [mailto:[email protected] <mailto:[email protected]>] >> >>Sent: 2015年4月9日 22:28 >> >>To: Lizhong Jin; 'Erik Nordmark'; [email protected] <mailto:[email protected]> >> >>Subject: RE: [nvo3] Encapsulation considerations >> >>Lizhong, >> >>[snip] >> >> [Lizhong] If the NVE and tenant is integrated into one device, then >> >>the issue >> >>could be solved by implementation. Because tenant know the entropy value >> >>of >> >>the first segment, and use the same value to the subsequent segment. So >> >>different implementation model could provide different entropy value. Or >> >>do we >> >>need other mechanism to mitigate this issue, e.g., fragment on NVE in >> >>draft-herbert-gue-fragmentation. >> >>[Lucy] IMO: NVO3 solution SHOULD avoid packet fragmentation. >> >>Draft-herbert-gue-fragmentation provides an option for a GUE application >> >>to do >> >>fragmentation but does not require doing it. GUE application decides if >> >>the >> >>fragmentation is needed or not. We should not separate two. >> >[Lizhong] fragmentation could not be avoided, because we are unable to >> >prevent >> >the tenant from fragmentation. This is the factor which makes the hashing >> >based >> >load balancing unoptimized. >> >> I'm not very familiar with host stacks. Do they actually fragment at the >> IP layer, or is it done at the transport layer before adding the IP >> header? I'm sure TCP must break the segments up before IP would fragment, >> but I'm not sure about UDP. >> >> - Larry >> >> _______________________________________________ >> nvo3 mailing list >> [email protected] <mailto:[email protected]> >> https://www.ietf.org/mailman/listinfo/nvo3 >> <https://www.ietf.org/mailman/listinfo/nvo3> > > _______________________________________________ > nvo3 mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/nvo3
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