This module provides a subtree to define OIDs so that
various routing 'policies' used by Cisco routers can be
expressed. This module defines only this 'policy' OID
space and doesn't define any other object.

As an example, these OIDs are required by at least the
following MIB objects: inetCidrRoutePolicy
( IP-FORWARD-MIB, RFC4292 ) and
mplsL3VpnVrfRteInetCidrPolicy ( MPLS-L3VPN-STD-MIB
RCS4382).  Both of these objects are defined as OBJECT
IDENTIFIERs without any defined semantics, to
differentiate between multiple entries to the same
destination in the tables inetCidrRoutePolicyTable and
mplsL3VpnVrfRteInetCidrTable.  These two objects
utilise a generalised notion of 'policy' defined in
this module.

The table inetCidrRouteTable of IP-FORWARD-MIB may list
multiple paths pointing out of (either):

* different interfaces with the same next-hop
        ipv6 route 2003::/64 interface gig0/0 2222::1
        ipv6 route 2003::/64 interface gig0/1 2222::1
* different interfaces with no next-hop
        ipv6 route 2003::/64 interface gig0/0
        ipv6 route 2003::/64 interface gig0/1

2003::/64 and 2222::1 represent an IPv6 route-prefix
and IPv6 next-hop respectively.

If these interfaces were in different zones, then the
'InetAddressIPv6z' type next-hop could distinguish
them. If they are in the same zone, then the two
interfaces refer to the same link.

The indices of inetCidrRouteTable are:
        inetCidrRouteDestType
        inetCidrRouteDest
        inetCidrRoutePfxLen
        inetCidrRoutePolicy
        inetCidrRouteNextHopType
        inetCidrRouteNextHop

The inetCidrRoutePolicy object, when instantiated with a
value from crpPolicyIfIndex, allows us to distinguish
the routing table entries mentioned in the examples
above.

REFERENCE

[1] IP-FORWARD-MIB (RFC4292)

[2] MPLS-L3VPN-STD-MIB (RFC4382)

[3] ifIndex, IF-MIB

[4] RFC 4291 IP Version 6 Addressing Architecture,
Section 2.2, Text Representation of Addresses.