[Nfd-dev] additional data between ethernet header and ndn header

[Junxiao Shi]

Hi Salvatore

Alex’s NFD version implements NDNLPv2. NDNLPv2 permits bare Interest/Data packets to appear on the wire. NFD’s NDNLPv2 implementation sends NDNLPv2 packets only if at least one NDNLPv2 header/trailer field is added.
In his experiment, if none of the NDNLPv2 header/trailer field is added, the packet would be bare Interest/Data and thus no additional octets appear on the wire.

Yours, Junxiao

> On Dec 15, 2015, at 2:59 PM, Salvatore Signorello <salvatore.signorello at uni.lu> wrote:
> 
> Thank you, Junxiao,
> 
> this clarifies things a lot ;)
> 
> If this protocol is always used by NFD, I wonder why Alex doesn't see the additional bytes when dumping a packet. Any clue about that?
> 
> Best,
> Salvatore
> 
> On 12/15/2015 04:37 PM, Junxiao Shi wrote:
>> Hi Salvatore
>> 
>> The payload of the first packet in the pcap is 50:37:51:08:00:00:00:00:00:00:00:11:54:2b:05:29:07:21:08:10:70:34:73:6f:66:74:77:61:72:65:73:77:69:74:63:68:08:0d:73:61:79:68:65:6c:6c:6f:77:6f:72:6c:64:0a:04:10:f2:e0:8f.
>> This appears to be NDNLPv1-TLV <http://redmine.named-data.net/projects/nfd/wiki/NDNLP-TLV> protocol, and can be interpreted as:
>> 
>> 50 37 // NdnlpData
>>    51 08 // NdnlpSequence
>>       00 00 00 00 00 00 00 11
>>    54 2b // NdnlpPayload
>>       05 29 // Interest
>>          07 21 // Name
>>             08 10 // NameComponent
>>                70 34 73 6f 66 74 77 61 72 65 73 77 69 74 63 68
>>             08 0d // NameComponent
>>                73 61 79 68 65 6c 6c 6f 77 6f 72 6c 64
>>          0a 04 // Nonce
>>             10 f2 e0 8f
>> 
>> Neither ndndump nor NDN dissector for Wireshark supports NDNLPv1-TLV.
>> In latest NFD, NDNLPv1-TLV is deprecated and replaced by NDNLPv2 <http://redmine.named-data.net/projects/nfd/wiki/NDNLPv2>, which will be supported by NDN dissector for Wireshark in #3197 <http://redmine.named-data.net/issues/3197>.
>> 
>> Yours, Junxiao
>> 
>> On Mon, Dec 14, 2015 at 3:52 PM, Salvatore Signorello < <mailto:salvatore.signorello at uni.lu>salvatore.signorello at uni.lu <mailto:salvatore.signorello at uni.lu>> wrote:
>> Hi Alex,
>> 
>> the pcap is in attach. I'm not using the latest version of the software tools and daemon, so if you either don't see the issue or are not able to reproduce it. I'll likely update the ndn software suite before asking you for more support.
>> 
>> Thanks,
>> Salvatore
> 
> -- 
> Salvatore Signorello
> PhD student @ SecanLab
> 
> Interdisciplinary Centre for Security, Reliability and Trust
> SnT, University of Luxembourg
> http://wwwen.uni.lu/snt/people/salvatore_signorello <http://wwwen.uni.lu/snt/people/salvatore_signorello>
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