[ndnSIM] What is the maximum size of a Data packet ?

Adrien Thibaud adrien.thibaud at tesa.prd.fr
Thu Mar 22 03:50:37 PDT 2018


Hi Susmit,

Thank you for your response.

Is there a specific reason that the NDN community choose 8800 octets as 
the maximum size in the code and not 1500 or 65535 for example ?

Then I have a question about how NDN communicates with upper and lower 
layers.
For the lower layer, there is a need to fragment and reassemble the NDN 
packet hop-by-hop and NDNLP has been defined for that.
But for the upper layer, how does the application know the maximum size 
of the NDN packet ?
Is there a layer between NDN and the application that is in charge to 
cut into NDN chunk the application data ?

Regards,
Adrien Thibaud


Le 20/03/2018 à 16:57, Susmit a écrit :
> Hi Adrien,
>
> The first is the theoritical maximum but that does not mean you should
> have a packet that big.
> By default, NDN uses 8800 byte packets, you can change it if you need to.
> There are several considerations you need to take into account before
> using large packets, fragmentation/reassembly, effect on router
> queues,
> effect on retransmission etc.
>
> On Tue, Mar 20, 2018 at 3:42 AM, Adrien Thibaud
> <adrien.thibaud at tesa.prd.fr> wrote:
>> Hi everyone,
>>
>> I am a little bit confused about the maximum size a NDN packet can have.
>>
>> In the specification
>> (http://named-data.net/doc/NDN-packet-spec/current/tlv.html), it says that
>> the length can be encoded on 8 octets, so the maximum size should be 2^64
>> octets.
>>
>> But in the code, there is a constante MAX_NDN_PACKET_SIZE set to 8800
>> (octet) and is define as the "practical limit of network layer packet size"
>> (https://github.com/named-data-ndnSIM/ndn-cxx/blob/ndn-cxx-0.3.4-ndnSIM/src/encoding/tlv.hpp#L39).
>>
>> Does anyone know which is the real maximum size ?
>>
>> Maybe the specification is not up-to-date ...
>>
>> Thank you,
>>
>> Adrien
>>
>> --
>> Adrien THIBAUD
>> PhD Student
>> INP Toulouse - ENSEEIHT
>> University of Toulouse, France
>> TéSA Cooperative research laboratory
>> IRIT Research Laboratory
>>
>> _______________________________________________
>> ndnSIM mailing list
>> ndnSIM at lists.cs.ucla.edu
>> http://www.lists.cs.ucla.edu/mailman/listinfo/ndnsim
>
>

-- 
Adrien THIBAUD
PhD Student
INP Toulouse - ENSEEIHT
University of Toulouse, France
TéSA Cooperative research laboratory
IRIT Research Laboratory



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