Wireshark · Wireshark-users: Re: [Wireshark-users] LLDP encoding

[Anders Broman <anders.broman@xxxxxxxxxxxx>]

 

 

From: Wireshark-users [mailto:wireshark-users-bounces@xxxxxxxxxxxxx] On Behalf Of sothy shan
Sent: den 13 juni 2017 10:03
To: Community support list for Wireshark <wireshark-users@xxxxxxxxxxxxx>
Subject: Re: [Wireshark-users] LLDP encoding

 

 

 

On Tue, Jun 13, 2017 at 8:41 AM, Jaap Keuter <jaap.keuter@xxxxxxxxx> wrote:

On 13-06-17 08:28, sothy shan wrote:
> Hi,
> I am just checking LLDP in mininet with OVS using wireshark.
> My question some data are encoding differently. I wish to know why it is?
> For example, chaissisId type is 1. But it is shown as 02 in your image.
>
> https://wiki.wireshark.org/LinkLayerDiscoveryProtocol?action="">
>
> Same thing I observed in my testing also. do you have any specific encodign
> technique for LLDP data.
>
> Thanks for your explanation.
>
> Best regards
> Sothy
>
>

Hi,

Be aware that the TLV type field is a subfield of this 16 bit field. it's only
the seven most significant bits that constitute the subfield in question.
Therefore the value of the subfield is '1', while the representation of the 16
bit field it comes from shows '0x0207'

Thanks,
Jaap

 

Thanks. I got it. One question is regarding portID. POrtID subtype is 7. It means locally assigned port id. In my case local port id is 1. it is encoded as  31. why? thanks again

Sothy 

 

Sound like the ASCII character 0x31 = “1”

 

Regards

Anders

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