RE: [802.3ae] MIB-II ifSpeed 32-bit limitation for 10G
The original MIB-II definition may be found in RFC 1213.
ftp://ftp.isi.edu/in-notes/rfc1213.txt
The interface specific aspects of MIB-II are being extended by the
Interfaces Group MIB - RFC 2863.
ftp://ftp.isi.edu/in-notes/rfc2863.txt
A quote from this document.
Experience in defining these media-specific MIB modules has shown
that the model defined by MIB-II is too simplistic and/or static for
some types of media-specific management. As a result, some of these
media-specific MIB modules assume an evolution or loosening of the
model. This memo documents and standardizes that evolution of the
model and fills in the gaps caused by that evolution.
Dealing with speeds higher than 4.2 Gb/s was one of the reasons that
required this evolution.
The DESCRIPTION clause of ifSpeed in RFC 2863 also includes the
information about what needs to be done for speeds higher than 4.2 Gb/s
- use ifHighSpeed. This probably answers the concern expressed by Danny.
Here is the relevant quote.
"An estimate of the interface's current bandwidth in bits
per second. For interfaces which do not vary in bandwidth
or for those where no accurate estimation can be made, this
object should contain the nominal bandwidth. If the
bandwidth of the interface is greater than the maximum value
reportable by this object then this object should report its
maximum value (4,294,967,295) and ifHighSpeed must be used
to report the interace's speed. For a sub-layer which has
no concept of bandwidth, this object should be zero."
I hope this helps.
Regards,
Dan
> -----Original Message-----
> From: James Colin [mailto:james_colin_i@xxxxxxxxx]
> Sent: Wednesday, October 03, 2001 7:42 AM
> To: lobod@xxxxxxxxxxxx; stds-802-3-hssg@xxxxxxxx
> Subject: RE: [802.3ae] MIB-II ifSpeed 32-bit limitation for 10G
>
>
>
> Danny,
> Can you please send a pointer in regards to this
> MIB-II definition? Where this definitions can be
> found?
> Thank you,
> James
>
>
> > -----Original Message-----
> > From: Danny Lobo [mailto:lobod@xxxxxxxxxxxx]
> > Sent: Tuesday, October 02, 2001 11:15 PM
> > To: stds-802-3-hssg@xxxxxxxx
> > Subject: [802.3ae] MIB-II ifSpeed 32-bit limitation
> for 10G
> >
> >
> >
> > Hello,
> >
> > The ifSpeed object defined in MIB-II's ifTable is
> 32-bits
> > wide and so will
> > hold only upto 4.2 Gbits/s. This works fine for
> existing,
> > relatively slower
> > topologies such as Fast Ethernet. However, due to
> the 32-bit
> > constraint, it
> > cannot be used for 10 GBE.
> > Any suggestions on how to overcome this problem?
> >
> > Thanks,
> >
> > Danny Lobo
> > NetScout Systems Inc
> > 310 Littleton Rd.,
> > Westford, MA 01886. USA
> > 978-614-4309
> >
>
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