On Sun, 2009-08-30 at 13:48 -0400, Mark Ellison wrote:
> On Sun, Aug 30, 2009 at 5:17 AM, Magnus Fromreide<
magfr@...> wrote:
> > Hello.
> >
> > According to rfc2742 agentxRegContext (octet string) is
> > "The context in which the session supports the objects in this
> > region. A zero-length context indicates the default context.
> > "
> >
> > Now I am would like to know how a zero-length context should be
> > represented?
> >
> The default context is an OCTET STRING of zero-length.
Not according to RFC 2741 6.1.1 ยง4.
In agentxRegContext we are looking a AgentX registrations and in this
domain it is explicitly stated that NON_DEFAULT_CONTEXT "" is distinct
from DEFAULT_CONTEXT but I can see no provision for the MIB to represent
that.
> How to represent this depends upon where it is being represented.
>
> On the wire, the tag is "OCTET STRING" the length is zero(0) and the
> value occupies no octets. There are numerous examples of OCTET
> STRINGs that may be zero-length in IETF standard MIB modules.
>
> For example, in the UsmUserTable, the usmUserPublic may be a
> zero-length string. In the USM MIB module, tthe usmUserPublic object
> definition shows he zero-length string as represented by the DEFVAL
> clause: { ''H } -- the empty string.
>
> A zero-length string and the empty-string are synonymous.
This is about the specific case of AgentX - we are talking about a
zero-length string and a non-existing string.
> - Mark
>
http://EllisonSoftware.com
