Re: [EFM-OAM] Question on invalid length/type field test

[Geoff Thompson <gthompso@xxxxxxxxxxxxxxxxxx>]

John-

At 05:49 PM 5/6/2003 +0200, John Messenger wrote:

> Hi,
>
> 57.5.3.2 deals with errored frames.  One of the listed criteria
> (from (d))
> is a "frame containing an invalid Length/Type field".  I
> presume this refers
> to the check in the RemovePad function in 4.2.9.  That is, I presume
> that
> this really means a "frame whose received length does not match the
> length
> recorded in the Length/Type field (if any)".
>
> Is this interpretation correct?  If so, I think a change in wording
> would be
> in order to make it clear that the check is not applicable in the case of
> a
> "Type" field.  I could not find a comment on this point in
> the recently
> posted comment list.

I would make no such assumption.
 From the inadequate description I would assume that it gets set if the
value in the Type/Length field  lies in the narrow range between the
max legitimate LLC dataSize (1500) and the lowest legitimate value of
Type (1536).

Values 1 - 1500 are legitimate as length interpretation.
Values of 1536 and above are legitimate as Type interpretation
(Ref: 802.3 cl 3.2.6)

Doesn't seem to be worth doing to me.

Regards,
        -- John Messenger

Geoff