Information Technology Reference
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Information Model Extensions (PCIMe) [4]. Both, PCIM and PCIMe derive from and
use classes defined in the DMTF Common Information Model (CIM) [5]. Moreover,
the IPsec Model and QPIM define the semantics of IPsec policy and QoS policy,
respectively. In fact, these models define the semantics that a policy specification or
language should implement according to the IETF.
However, IETF lacks an information model for routing. Although it defines the
Routing Policy Specification Language (RPSL) [6] which is a language to specify
routing policies, is not based on any particular model and, moreover, there is no
definition of a model to be used over it.
Thus, the definition, modeling and deployment of a model for routing policies
based on a well-recognized standard, such as CIM, will enable the intra- and
inter-domain management of different network services (such as, IPsec, QoS and
routing) in a uniform manner.
This paper is intended to provide the results of modeling routing policies using
CIM. It also describes how to take advantage of the Policy-based Network
Management (PBNM) paradigm to develop such modeling. The last part of the paper
is devoted to report on the development of the proposed modeling using for this some
components deployed as part of the Euro6IX (European IPv6 Internet Exchanges
Backbone) EU-funded IST project [8].
2 Representing Routing Policies in CIM
The Common Information Model (CIM) is an approach from the DMTF (Distributed
Management Task Force) that applies the basic structuring and conceptualization
techniques of the object-oriented paradigm to provide a common definition of
management-related information for systems, networks, users, and services. The
major benefit of specifying routing policy rules in this way is that an organization can
utilize a common model that can be shared amongst all network nodes.
Policy model provides a framework for specifying configuration and operational
information in a scalable way using rules composed of conditions and actions. It
includes, among other elements, policy rules, policy groups, and policy conditions
and actions, both in generic and vendor-specific form.
We propose a set of classes and associations to extend the CIM Policy Scheme to
express routing policies (see Figure 1 for their representation in UML). Our proposal
is based on the reposition of the class
RoutingPolicy
of CIM Network Scheme in CIM
Policy Scheme.
RoutingRule
is used to implement routing policies. It defines a common connection
point for associating conditions such as
PacketFilterCondition
and
PolicyTimePeriodCondition
, and network actions (
RoutingAction
). One of the most
important uses of this class is to change the routing policy by changing values of
various attributes in a consistent manner.
RoutingAction
is the base class for the various types of network actions. There are
essentially three types of actions: forward the traffic unmodified, forward the traffic
but modify either the attributes describing the route and/or other attributes that define
how to adapt the traffic (e.g., its ToS -Type of Service- byte settings), or prevent the
traffic from being forwarded. The class properties of
RoutingAction
correspond with
the class properties of
RoutingPolicy
.
