Re: JUMBO FRAMES

It is a tcp based app. Communication is within the same vlan . For routed
traffic , i am sure MSS won't be negotiated above PMTU. But for traffic
between the same VLAN , does some thing like that happen(PMTU) ?
I am using AIX iptrace + wireshark.

Switch isn't configured for Jumbo frames and i see server sending frames >
1500.

In case of Jumbo frames + TCP , do both parties agree on a larger MSS in SYN
?

Also do they need rfc 1323 (Win scale) agreed ?

On Thu, Jun 9, 2011 at 2:39 AM, Marko Milivojevic <markom_at_ipexpert.com>wrote:

> Those retransmissions are implemented on the application layer and may
> not be seen as such unless you were specifically looking for them. On
> the other hand, TCP retransmissions will be immediately identified as
> such. Have you ever used tcpdump?
>
> --
> Marko Milivojevic - CCIE #18427
> Senior Technical Instructor - IPexpert
>
> FREE CCIE training: http://bit.ly/vLecture
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>
> On Wed, Jun 8, 2011 at 13:19, Carlos G Mendioroz <tron_at_huapi.ba.ar>
> wrote:
> > Why is that you won't see retransmissions if it is not TCP ?
> > Try SIP over UDP, you will see retransmissions.
> > NFS over UDP ? Same thing.
> > Just because TCP is not in charge of them does not mean they will not
> take
> > place :)
> > -Carlos
> >
> > Marko Milivojevic @ 8/6/2011 15:34 -0300 dixit:
> >>
> >> Is the application TCP? If it isn't, you won't see the retransmissions.
> >>
> >> And yeah - traffic is very likely being dropped by the switch, but
> >> lacking any command output, it's hard to say for sure :-)
> >>
> >> --
> >> Marko Milivojevic - CCIE #18427
> >> Senior Technical Instructor - IPexpert
> >>
> >> FREE CCIE training: http://bit.ly/vLecture
> >>
> >> Mailto: markom_at_ipexpert.com
> >> Telephone: +1.810.326.1444
> >> Web: http://www.ipexpert.com/
> >>
> >> On Wed, Jun 8, 2011 at 08:32, Bernard Steven <buny.steven_at_gmail.com>
> >> wrote:
> >>>
> >>> What will happen if a server sends a jumbo frame to the connected
> switch
> >>> that does not support (not configured) Jumbo frames ?
> >>>
> >>> My problem is when i capture traffic from server IF (tcpdump ) , i see
> >>> large
> >>> frames (1518<) , in the mean time , switch is not configured for JF and
> >>> also
> >>> i don't see any retransmissions in tcpdump. (assuming switch discards
> the
> >>> jumbo frame). And also i dont have any visibility on the other end of
> the
> >>> communication. Some how , application does not work.Switch is a 4948.
> >>>
> >>>
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> >>
> >>
> >>
> >>
> >
> > --
> > Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina

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Received on Thu Jun 09 2011 - 07:12:15 ART