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 4:22 AM, Carlos G Mendioroz <tron_at_huapi.ba.ar> wrote:

> Where is that defined ?
>
> (That an NFS controlled retransmission is not a retransmission, that is ?)
> -Carlos
>
> Marko Milivojevic @ 08/06/2011 19:38 -0300 dixit:
>
> You would still be wrong, as retransmission as such would be only
>> those performed by the control protocol, i.e. TCP in this case. What
>> applications do is application behavior, not network control.
>>
>> Then again, that's being picky.
>>
>> --
>> 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 15:17, Carlos G Mendioroz <tron_at_huapi.ba.ar>
>> wrote:
>>
>>> Sure,
>>> I was just not ok with calling "retransmissions" only those packets
>>> recognized as such by tcpdump.
>>>
>>> I've learned to be picky with the nomenclature of things, my bad.
>>> -Carlos
>>>
>>> Marko Milivojevic @ 08/06/2011 18:09 -0300 dixit:
>>>
>>>> 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
>>>>
>>>> Mailto: markom_at_ipexpert.com
>>>> Telephone: +1.810.326.1444
>>>> Web: http://www.ipexpert.com/
>>>>
>>>> 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
>>>>>
>>>>> --
>>> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>>>
>>>
> --
> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina

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Received on Thu Jun 09 2011 - 10:39:17 ART