On Dec 19, 2012, at 1:27 PM, Stuart Werbner <swerb...@us.ibm.com> wrote:
> I am requesting a new LINKTYPE_ (LINKTYPE_IB) value for IP over Infiniband
> be reserved, in order to properly support this protocol within tcpdump and
> libpcap for upcoming AIX kernel releases.
So you're using LINKTYPE_ values, rather than SNMP interface type values, as
the network type in pcap files now? Good.
If you're writing nanosecond time stamps to files, are you now using a1 b2 3c
4d rather than a1 b2 c3 d4 as the magic number, so that programs or libraries
reading the files can determine what the time stamp resolution is?
(And speaking of AIX's libpcap/tcpdump, there's AIX support in the tcpdump.org
libpcap, but it seems to be tripping across some bugs in AIX's BPF
implementation, at least in the versions of AIX against which the people
reporting the bugs tried it.)
> If this value is already defined, please indicate that.
>
> I have discovered that within an AIX kernel header file, DLT_IB (Data-link
> Level Type) is defined, but I believe we are still in need of a Link-Layer
> Header Type.
>
> Here are the RFCs related to IP over Infiniband:
> * RFC 3827
> * RFC 4391
In the existing link-layer header type list:
http://www.tcpdump.org/linktypes.html
there's a LINKTYPE_IPOIB value, in which the packet data is as described in
section 6 of RFC 4391, starting with the 4-octet encapsulation header.
RFC 3827 just speaks of a snoop link-layer header type value for IP-over-IB,
referring to a "work in progress" document; as RFC 3827 came from Sun, and as
LINKTYPE_IPOIB was provided in response to a request from somebody from
Sun^WOracle, the snoop link-layer header type probably refers to the same thing.
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