Subject: A question on Mcast MIB?

From: Haixiang He <[email-masked]>
Date: Tue, 17 Oct 2000 18:38:06 -0400

In RFC 2932, IPv4 Multicast Routing MIB, it says:

ipMRouteInIfIndex OBJECT-TYPE
    SYNTAX     InterfaceIndexOrZero
    MAX-ACCESS read-only
    STATUS     current
    DESCRIPTION
            "The value of ifIndex for the interface on which IP
            datagrams sent by these sources to this multicast address
            are received.  A value of 0 indicates that datagrams are not

            subject to an incoming interface check, but may be accepted
            on multiple interfaces (e.g., in CBT)."
    ::= { ipMRouteEntry 5 }

Assume the datagrams is coming from interface 0, e.g. ifIndex=0, then
how do you explain this value?

Thanks,

Haixiang

---

From: Keith McCloghrie <[email-masked]>
Date: Tue, 17 Oct 2000 16:40:07 -0700 (PDT)

InterfaceIndexOrZero is defined in RFC 2863 as:

  InterfaceIndexOrZero ::= TEXTUAL-CONVENTION
      DISPLAY-HINT "d"
      STATUS       current
      DESCRIPTION
            "This textual convention is an extension of the
            InterfaceIndex convention.  The latter defines a greater
            than zero value used to identify an interface or interface
            sub-layer in the managed system.  This extension permits the
            additional value of zero.  the value zero is object-specific
            and must therefore be defined as part of the description of
            any object which uses this syntax.  Examples of the usage of
            zero might include situations where interface was unknown,
            or when none or all interfaces need to be referenced."
      SYNTAX       Integer32 (0..2147483647)

Keith.