Re: Pcap link type of InfiniBand

[Guy Harris <guy () alum mit edu>]

On Jul 6, 2016, at 11:42 PM, Tal Attaly <talat () mellanox com> wrote:

> I understand that LINKTYPE_ value just saves an id for the link type, but parsing code for InfiniBand is exist in 
> wireshark - under ERF link type (Extensible Record File), so I wonder why not using the actual link type of 
> InfiniBand.

LINKTYPE_ values are assigned numerically in order.

LINKTYPE_ERF is 197.

LINKTYPE_INFINIBAND is 247.

I.e., at the time LINKTPE_ERF was assigned, LINKTYPE_INFINIBAND *did not exist*, so nobody *could* use it!

LINKTYPE_ERF was requested by Endace (the creators of ERF) to allow all metadata from Endace DAG cards to be included 
in pcap captures.  ERF files support multiple link-layer types, one of which is InfiniBand, as they had, at least at 
one point, hardware to capture InfiniBand traffic:

        
http://www.endace.com/endace-delivers-single-device-solution-for-infiniband-data-capture-filter-and-analysis.html

so LINKTYPE_ERF could be used for InfiniBand captures - and, in fact, if the capture was done with Endace's InfiniBand 
hardware, it's quite logical that it would have been used for the capture.
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