Ntanzi M. Carrilho, Neco Ventura
Department of Electrical Engineering, University of Cape Town, Rondebosch, Cape Town, South Africa
Policy-based Network Management, DiffServ, XML-based Network Management, NETCONF.
A design, implementation, and evaluation of a Policy-based Management framework for DiffServ networks
using XML technologies is presented. XML is used for policy representation throughout the entire policy life
cycle, as well as in the communication protocol, reducing development costs, while promoting clarity, simplic-
ity, and interoperability. Furthermore, performance evaluation results show that the proposed scheme generates
less network traffic than its COPS-PR counterpart when protocol messages are compressed. Moreover, XML
messages generate higher processing delays. The added processing overhead caused by compression to XML
messages is very small, thus the gains in reduced network traffic generated outweigh the losses in terms of
processing delays.
Today Internet traffic is highly diverse. Applications
have different requirements in terms of bandwidth,
delay, loss and jitter. The Internet protocol suite was
originally designed to provide best-effort services; it
was designed to deliver packets to their destination
without any Quality of Service (QoS) guarantees, re-
sulting in unpredictable behaviour of applications.
In order to counter this behaviour a few technolo-
gies were designed to complement the IP infrastruc-
ture to it capable of handling traffic with different QoS
needs. One of these technologies is the Differenti-
ated Services (DiffServ) (Blake et al., 1998) network
architecture. DiffServ was designed to be a scalable
service differentiation architecture for the Internet. It
achieves scalability by classifying and possibly condi-
tioning traffic streams on the edge of the network, ac-
cording to their requirements. On the core of the net-
work, resources are allocated to these streams based
on their classification or Per-Hop Behaviour (PHB).
The management requirements for DiffServ net-
works differ from those of simple IP networks. Al-
though the DiffServ technology is relatively simple,
the initial setup and configuration of hundreds of de-
vices can be complex and daunting. Policy-Based
Network Management (PBNM) provide mechanisms
to simplify and automate the management and admin-
istration of these networks, therefore reducing man-
agement costs.
The Internet Engineering Task Force (IETF) is
working on the standardisation of PBNM technolo-
gies such as the Common Open Policy Service proto-
col for Policy Provisioning (COPS-PR) (Chan et al.,
2001) and its associated data definition language, the
Structure of Policy Provisioning Information (SPPI)
(McCloghrie et al., 2001). COPS-PR messages are
usually encoded according to the Basic Encoding
Rules (BER), a binary encoding scheme. As a conse-
quence the protocol is not easy to use, understand, or
debug. Up to now, COPS-PR and SPPI have failed to
gain considerable market acceptance (Schoenwaelder
et al., 2003), mainly because network operators feel
that COPS-PR protocol does not address their require-
ments (Schoenwaelder, 2003).
On the other hand the limitations of the Simple
Network Management Protocol (SNMP) as a suit-
able mechanism for device configuration manage-
ment are driving research on the applicability of XML
(the eXtensible Markup Language) to device con-
figuration management. The IETF has charted the
Network Configuration (NETCONF) Working Group
M. Carrilho N. and Ventura N. (2007).
In Proceedings of the Third International Conference on Web Information Systems and Technologies - Internet Technology, pages 72-79
DOI: 10.5220/0001281500720079
(WG) with the aim of creating a network configura-
tion protocol using XML technologies. NETCONF
(Enns, 2006) enables devices to communicate with
each other using Remote Procedure Calls (RPC) en-
coded in XML.
Motivated by the failure of COPS-PR, we present
the design, implementation, and evaluation of a
policy-based management architecture for DiffServ
networks using NETCONF as the device communi-
cation protocol, along with XML Schema and XML
for policy modelling and representation, respectively.
There are several advantages of using XML for both
data representation and the exchange protocol. XML
provides a format that is both machine and human-
readable, which is useful in the debugging and de-
ployment of the tool. XML Schema provides power-
ful and extensible modelling mechanisms capable of
modelling information of arbitrary complexity. Due
to the widespread XML document processing tools,
the effort needed in the development of the PBNM
system is reduced. Perhaps the most important incen-
tive for the use of XML for data representation and
protocol messages in a PBNM system is that it im-
proves interoperability between heterogeneous man-
agement systems or even between elements within the
same system, and provides a common format for the
various policy representation levels.
The remainder of this paper is organised as fol-
lows: Section 2 presents a brief overview of NET-
CONF. Section 3 presents an overview of relevant
work related to the one presented here. Section 4
introduces the proposed policy framework. Section
5 proceeds by describing the proposed PBNM ar-
chitecture and its main components. Section 6 pro-
vides measurement results and finally, conclusions are
drawn in Section 7.
NETCONF (Enns, 2006) is an XML based proto-
col created specifically for network device configu-
ration. It uses a XML RPC mechanism to expose
a formal Application Programming Interface (API)
through which managers and agents communicate.
The protocol defines a base set of operations to re-
trieve, edit and copy partial or entire device configu-
rations. This base set of operations can be extended
by adding capabilities.
NETCONF is a connection-oriented protocol
which requires a persistent connection between the
manager and the agent although it is not bound to any
particular transport protocol. Its connections must
provide authentication, data integrity, and privacy.
NETCONF depends on the transport protocol for this
capability. SSH, SOAP over HTTP and BEEP may be
used. Although we are not using any of these proto-
cols in our current implementation, in future we are
planning to use SSH to secure sessions.
This section will review research work addressing is-
sues relating to policy representation and transporta-
tion using XML based technologies.
(Beller et al., 2004) propose a framework for
defining reusable business-level policies for DiffServ
using XML for policy representation. Policies are de-
signed following a modular approach to increase re-
usability. Xpointers are used to locate reusable pol-
icy fragments placed in a reusable policy container.
Although this is a good approach, we think that us-
ing the XInclude standard would yield a better result,
since it would automate the parsing and inclusion of
re-usable fragments. This is the approach followed in
the research project.
(Clemente et al., 2005) propose a similar PBNM
architecture focusing on IP Security (IPSec). Similar
to the scheme proposed in our paper, XML is used for
representation of policies during their entire life cy-
cle. High-level policies are modelled based on PCIM
and lower-level policies are modelled based on the
IPSec PIB. A Model-Level mapping scheme is used
for lower level policy mapping. PIB attributes are
mapped to XML elements instead of attributes, result-
ing in XML documents that are even more verbose.
The proposals mentioned above only partially
solve the problems stated in Section 1. This is due to
the fact that they still use COPS-PR to provision poli-
cies. (Franco et al., 2006) and recognise in their work
the potential of using XML-based exchange protocols
for PBNM. They present two communication mod-
els for policy provisioning, based on NETCONF and
SOAP, respectively. The study shows, as compared
to COPS-PR, that both schemes waist more band-
width. An interesting finding is that if compression is
used for XML messages both schemes consume less
bandwidth than COPS-PR. The study concludes that
if NETCONF or SOAP are to be used for policy pro-
vision careful attention must be paid to the modelling
of the communication between devices. The archi-
tecture presented in this paper uses NETCONF for
device communication and the communication model
used is very similar to the one presented in (Franco
et al., 2006).
In summary, whereas (Beller et al., 2004) and
(Clemente et al., 2005) use COPS-PR for policy pro-
visioning, we employ NETCONF. We think that this
is a step forward because by using an XML-based
provisioning protocol coupled with XML policy rep-
resentations we simplify the internal structure of the
PBNM system and reduce development costs. More-
over, (Franco et al., 2006) use XML-based policy pro-
visioning schemes but their work focuses on low level
QoS policies. In this paper we aim to present a more
comprehensive policy framework by adding a layer of
abstraction that focuses on the network instead of the
various managed devices and simplifies the adminis-
tration process.
The IETF and the Distributed Management Task
Force (DMTF) have jointly developed object oriented
models for policy representation, namely the Policy
Core Information Model (PCIM) (Moore et al., 2001)
and its extensions (PCIMe) (Moore, 2003). PCIM and
PCIMe define the generic structure of a policy and can
be extended to enable developers and administrators
to define policies of different types. The Policy QoS
Information Model (QPIM) (Snir et al., 2003) is a fur-
ther extension of PCIM and PCIMe designed specifi-
cally for the representation of QoS policies. The pol-
icy framework presented here is based on these stan-
Figure 1 presents an overview of the policy frame-
work used in our work. Business-level policies are
used to express the general business requirements of
the network. They represent the highest level of pol-
icy abstraction and are generally presented in a user
friendly format. Business-level policies can be mod-
elled using PCIM extended to model policies in a spe-
cific domain, e.g. QoS.
Figure 1: Policy hierarchy.
This work focuses on the two middle levels of
Figure 1, more specifically, network and device-level
policies. Network-level policies represent generic
network operational and configuration information
that is independent of any specific device but is de-
pendent of general QoS mechanisms such as the type
of queue management strategy employed. We model
network-level policies based on the PCIM/PCIMe
and QPIM information models. We chose to model
network-level policies based on these standards be-
cause they are very flexible, widely accepted, and do
not depend on any storage technology.
Device-level policies are specific for a given de-
vice. The PBNM system translates network-level
policies to device-level policies based on the capa-
bilities supplied by each device. While network-
level policies provide a common level of abstrac-
tion required to manage multiple devices with poten-
tially different capabilities, device-level policies pro-
vide adequate policies for each device based on the
device’s capabilities. In this work we model device-
level policies based on the DiffServ Policy Informa-
tion Base (PIB). We opted to use the DiffServ PIB, in
favour of QDDIM (Information model for Describing
Network Device QoS Datapath Mechanisms) (Moore
et al., 2004) because of its simplicity and acceptance.
Furthermore COPS-PR is designed to transfer poli-
cies modelled using the DiffServ PIB, and in order
to provide a fair comparison between the alternative
policy provision scheme presented in this paper and
traditional COPS-PR schemes both schemes have to
be based on the same model.
Device-level policies provide a common configu-
ration format for multiple network devices. But the
specific configuration commands applied to devices
may differ. Therefore the final translation stage in the
policy life cycle is the translation of device-level poli-
cies to device-specific configuration commands.
4.1 Network-Level Policies
As mentioned in the previous section we model
network-level policies based on PCIM/PCIMe and
QPIM. These models are independent of any stor-
age technology allowing various data models to be
designed and implemented according to a single uni-
form model. Some of their strengths are that they al-
low for policy rule nesting and re-usability. Rule nest-
ing enables complex policy rules to be constructed
form multiple simpler rules enhancing the manage-
ability and scalability of the policy framework.
In order to gain advantage from these features
these information models have to be mapped to a suit-
able data model. By using XML for policy repre-
sentation and storage we ease that mapping. XML
is renowned for its ability to represent data of almost
arbitrary complexity, easily enabling data nesting and
WEBIST 2007 - International Conference on Web Information Systems and Technologies
There are two possible mapping schemes: schema
mapping and meta-schema mapping (Youn and Hong,
2003). A Schema Mapping is one in which the XML
Schema is used to describe CIM classes, and CIM In-
stances are mapped to valid XML Documents for that
schema. XML element names and attributes are taken
directly from the corresponding CIM element names
and attributes respectively. A Meta-schema Mapping
is one in which the XML schema is used to describe
the CIM meta-schema, and both CIM classes and in-
stances are valid XML documents for that schema.
CIM element names are mapped to XML attribute or
element values, rather than XML element names.
In this work we opted for the schema mapping
since it provides a more intuitive representation of
PCIM/PCIMe and QPIM in XML. Moreover because
XML Schema is used to describe CIM classes, this
mapping scheme gives us more validation power. The
mapping strategy adopted in this work is as follows.
The mapping of CIM structural classes is straight
forward. There is a one-to-one mapping of CIM struc-
tural classes to XML elements. CIM class attributes
are mapped to the corresponding XML element at-
tributes. Only concrete CIM classes are mapped. Ab-
stract classes are omitted and their attributes are in-
herited by the closest concrete descendant class.
The mapping of CIM associations is more tricky
because of the need to enable data re-usability. When
the association does not involve reusable information
the association class is not represented. Its attributes
are mapped to the structural representing the Depen-
dent/PartComponent of the association.
When the association involves reusable informa-
tion the association class is explicitly mapped to an
XML element. The end of the association represent-
ing the Dependent/PartComponent class is mapped to
an XInclude element. XInclude is a World Wide Web
Consortium (W3C) standard that enables the inclu-
sion of a fragment of an XML document within an-
other. XInclude uses XPointer, another W3C stan-
dard, to determine what part of a document to in-
clude. The advantage of using XInclude is that it
allows for policies to be created in a modular fash-
ion. Furthermore, some native XML databases al-
ready come equipped with an XInclude processor that
replaces xinclude elements with the XML fragments
they point to, making it very easy to deploy solutions
that benefit from XInclude. In order to increase ro-
bustness, XML policies are validated before and after
The extract below corresponds to a network-
level policy that models an Expedited Forwarding
(EF) class suitable for IP telephony. In the ex-
ample xinclude elements are used to locate and
include re-usable actions and conditions. The
example also demonstrates how associations (e.g.
PolicyConditionInPolicyRule) that involve
re-usable policy elements are used.
<PolicyRule Name="EFedgePolicyRule">
<xi:include href="/db/QoSPolicies/
@Name=’EFedgeConditions’])" />
<CompoundPolicyAction Name="EFedgeAct">
<xi:include href="/db/QoSPolicies/
<xi:include href="/db/QoSPolicies/
4.2 Device-Level Policies
Device-level policies are modelled based on the Diff-
Serv Policy Information Base (PIB). The DiffServ
PIB (Chan et al., 2003) follows the principles of
the DiffServ architecture
described in (Blake et al.,
1998) and its informal management model presented
in (Bernet et al., 2002). It describes a structure for
specifying management information that can be trans-
mitted to a network device using COPS/COPS-PR.
The DiffServ PIB models TCB elements as Provi-
sioning Classes (PRCs) and Instances of these classes
(PRIs), identified by unique Provisioning Instance
Identifiers (PRIDs).
As with network-level policies, there are two pos-
sible schemes for mapping SPPI-based PIB to a XML
format: model-level mapping and meta-model-level
mapping (Youn and Hong, 2003). A model-level
mapping is one in which each PIB object is mapped
to a XML Schema fragment. XML element names or
attributes are taken directly from PIB object names.
A meta model-level is one in which the XML Schema
gives a generic description of the PIB. In this case, in-
stead of mapping PIB objects to XML element names
or attributes, PIB objects are mapped to XML at-
tributes values defined by the XML Schema.
For this work we used the model-level mapping
because it provides a more intuitive representation
of the PIB in XML, and it gives us more validation
For the mapping strategy each PRC is mapped to
a XML element and instances of that PRC (i.e. PRIs
or PIB objects) are mapped to corresponding XML
attributes. We chose to map PRIs to XML attributes
instead of child elements as in
(Clemente et al., 2005)
because this way the resulting XML documents be-
come less verbose.
As an exception, PRIs or objects
that refer to other Provisioning Instance Identifiers
(PRIDs), such as the ClfrElementSpecific ob-
ject, are mapped to child XML elements. This is due
to the fact that
PRIs containing PRIDs are at times
optional, and can be left out
. These elements have an
attribute Location, which has as value, an Xpath
expression locating the desired PRC element. PRCs
of the same type are grouped within the same PRC
container, so that XML documents become more con-
venient for reading and processing.
Figure 2 depicts a very simplified version of a
TCB. In the figure the blocks are PRIs. The arrows
depicted are linking PRIs using their PRIDs as refer-
Figure 2: DiffServ PIB TCB.
The XML fragment bellow corresponds to the
mapping of the highlighted portion of Figure 2. Note
that although all elements that represent the DiffServ
PIB belong to a specific namespace (i.e. ds-pib),
we chose to leave the namespace prefix out of the fol-
lowing example for simplicity.
<IpFilterTable BaseFilterPrid="3"
<ClfrElementTable ClfrElementPrid="1">
<ClfrElementSpecific Location=
<ClfrElementNext Location=
<MeterTable MeterPrid="1">
There are many advantages of using a XML over bi-
nary SPPI for policy representation. XML-based PIB
is clear, easy to use and debug. The Xpath-based nam-
ing scheme presented here is more clear and easy to
understand than the Object Identifier (OID) naming
scheme employed by SPPI-based PIBs. As depicted
in the XML fragment above, the generated XML doc-
ument is easy readable and self-describing. Further-
more, because XML parsers are widely available, de-
velopers spend less time worrying about the details of
the parser itself and more time working on the appli-
cation. This certainly reduces the development cycles
of PBNM applications.
Figure 3 presents an overview of the our proposed
PBNM architecture. It is based on the PBNM archi-
tecture defined by the IETF (Yavatkar et al., 2000).
The components are the same, whereas the technolo-
gies used are different.
Firstly, a native XML database serves as the pol-
icy repository. This is a natural choice taking into
consideration that we only use XML for policy repre-
sentation. Some native XML databases already come
equipment with an XInclude processor and an XML
parser and validator’. That way we do not have to
worry about the parsing, validating and processing of
XML documents, focusing only on policy authoring.
Furthermore, we can organise policies in the database
in a modular fashion, as described in Section 4.1, us-
ing XInclude to include the various reusable XML
policy fragments.
Figure 3: Proposed PBNM architecture.
Secondly, policy provisioning is done through
NETCONF instead of COPS-PR. Because NET-
CONF is XML-based it is simple, portable, easy to
understand, program and debug. Additionally we
can use the same tools to process protocol messages
and configuration data, greatly reducing development
As per Figure 3, the management station serves
WEBIST 2007 - International Conference on Web Information Systems and Technologies
as the interface between the administrator and the
PBNM system. It is used to create, insert and edit
policies in the XML database through the standard
API exposed by the database server. It also monitors
the operation of various PDPs.
The native XML database stores policies in XML
format. It automatically validates them against well
defined XML Schemas. The database server includes
a XInclude processor that automatically processes
XInclude elements, locating and including fragments
of policies stored in reusable policy collections. The
other system components interact with the database
server through a standard API.
The PDP is the central part of the system. It is
responsible for fetching network-level policies stored
in the database using the roles supplied by PEPs
to discriminate between policies. It validates the
fetched policies. Translates network-level policies
into device-level based on the device capabilities sup-
plied by PEPs; sets up a scheduler according to the
time conditions attached to each policy and sends
device-level policies to PEPs using the NETCONF
API exposed by them.
The PEPs enforce policies on the DiffServ routers.
They are responsible for receiving and translating
common device-level policies into a set of commands
specific for the type of router being managed, and
feeding the resulting commands to the router.
5.1 The Communication Model
The communication model employed in this scheme
is different from that employed by schemes that use
COPS-PR. COPS-PR sees the PDP as the server and
the PEP as the client. The PEP opens the connection
with the server. In case of failure the client is respon-
sible for re-establishing the lost connection.
On the other hand NETCONF employs a
client/server model where the PDP is the client
whereas the PEP is the server. The PDP is configured
with a list of PEPs that it manages. It is responsible
for initiating communication with all PEPs, request-
ing roles and capabilities of each device, and sending
policy decisions. The PDP has to keep track of all
open sessions to PEPs. In case of connection failure
the PDP is responsible for re-establishing the lost con-
nection. This characteristic makes this scheme less
attractive than the COPS-PR scheme, with regard to
failure recovery.
5.2 Implementation Details
This Section gives a brief overview of some of the
details regarding the implementation of the proposed
The native XML database used was the eXist
(Meier, 2006) open source database. It has XQuery
support to run server side applications. It also comes
equipped with an XInclude engine to process xinclude
elements. We use the standard XML:DB API pro-
vided to interact with the repository.
The PDP was programmed as a multi-threaded
Java client. We used the Java API for XML Pro-
cessing (JAXP) to ease the parsing, validation, and
processing of policies. JAXP provides an abstraction
layer between the PDP application and the XML doc-
uments through the Document Object Model (DOM)
and the Simple API for XML (SAX). The PDP has
a simple NETCONF stack used to communicate with
The Yenca (Bourdelon and State, 2004) NET-
CONF agent prototype was used as basis for the PEP
server. Yenca is a simple NETCONF agent writ-
ten in C by the LORIA-INRIA Lorraine Madynes
Research team, in France. The agent has a modu-
lar design allowing users to extend it with modules
that are loaded dynamically. We extended the Yenca
agent with a DiffServ module that supports the Diff-
Serv PIB. The module validates policies and trans-
lates them to router-specific configuration commands.
The advantages of using XML in any system are its
simplicity, clarity, and portability. On the other hand
that design choice can be costly in terms of network
usage and processing overhead because of the verbose
nature of XML documents. This Section presents
a performance comparison between the XML-based
PBNM system proposed in this paper and a PBNM
system using COPS-PR as the management protocol
with a SPPI-based DiffServ PIB.
6.1 Provisioned Policies
DiffServ policies were provisioned to core DiffServ
routers in four iterations, going from simple to com-
plex. Table 1 gives a summary of the four iterations.
In iteration 1 the PDP sends policies correspond-
ing to the Expedited Forwarding (EF) class suitable
for IP telephony. In iteration 2 it adds an Assured For-
warding 4x class (AF4x) designed to support multi-
media conferencing applications. In the third iteration
we add an AF3x class for multimedia streaming appli-
cations. Finally, in iteration 4, a AF1x class suitable
for applications that generate high throughput data is
Table 1: Provisioned policies.
Number of
1 EF 67
2 EF, AF4x 213
3 EF, AF4x, AF3x 293
EF, AF4x,
AF3x, AF1x
added. These policy classes were created following
the guidelines recommended by (Babiarz et al., 2006).
6.2 Experimental Environment
Our experimental setup is composed of two machines
acting as a PDP and PEP respectively. The PDP is
an AMD Sempron 2600+, with 705MB RAM, run-
ning a Fedora Core 4 operating system. The PEP is a
Pentium II, 233 MHz, with 450 MB RAM, running a
Fedora Core 4 operating system. The PEP serves as
proxy to an edge DiffServ router implemented using
the Linux traffic control libraries. The the two ma-
chines are connected to each-other via a 100 Mbps
The overhead imposed by our implementation was
compared to that of the COPS-PR/DiffServ imple-
mentation developed by the Networks and Protocols
Group of the Tampere University of Technology. We
chose this implementation because like Yenca, it is
written in C, and it is simple and small, providing a
good basis for comparison.
The parameters taken into consideration when
comparing the performance of both schemes were
network usage when the PDP sends decisions to the
PEP, and the processing delays generated when the
PEP parses and saves policy decisions.
6.3 Network Usage
We compared the network traffic generated by each
scheme for each policy provisioning iteration. Given
the verbose nature of XML documents we decided to
add zlib compression to XML messages and verify
its effect on the traffic generated. Figure 4 shows the
resulting measurements.
The results show that NETCONF generates more
traffic than COPS-PR. As the number of objects trans-
mitted increases, the amount of traffic NETCONF
generates as compared to that of COPS-PR also in-
When zlib compression is added to NETCONF
messages, and the number of objects transmitted is
small, both schemes generate roughly the same net-
work traffic. However, as the number of objects in-
creases NETCONF outperforms COPS-PR. This is
due to the fact that XML documents are structurally
repetitive, resulting in good compression levels for
large documents.
Figure 4: Network usage.
In cases where bandwidth is scarce, compression
schemes such as XMill can be used. These schemes
are tailored specifically for XML documents, achiev-
ing better results than general compression schemes.
6.4 Processing Delay
The second parameter considered was the time taken
for the PEP to parse, decode and save policy deci-
sions. Figure 5 shows the resulting measurements.
Figure 5: Processing delays.
Not surprisingly the measurements show the
scheme proposed in this paper generates more pro-
cessing overhead. The XML messages are more pro-
cessor intensive than BER messages because they go
through complex parsing and validation before data is
extracted. However, as network devices become more
powerful the processing overhead caused by XML
documents becomes a less relevant issue.
The added processing overhead generated by
adding compression to documents is very small,
therefore with the use of compression the gains in re-
WEBIST 2007 - International Conference on Web Information Systems and Technologies
duced network traffic generated outweigh the losses
in terms of processing overhead.
In this paper we presented the design, implementa-
tion, and evaluation of a PBNM system based on
XML technologies. XML is used for policy represen-
tation throughout the entire policy life cycle, as well
as in the communication protocol, reducing develop-
ment costs, while promoting clarity, simplicity, and
interoperability. As exemplified, XML-based (net-
work and device-level) policies are self-describing,
and easy to use.
The performance comparison results show that the
scheme proposed in this paper generates less network
traffic than its COPS-PR counterpart when protocol
messages are compressed. The difference becomes
more significant as the number of objects transferred
On the other hand the measurements show that the
XML-based scheme proposed here generates more
processing delays than COPS-PR due to the fact that
XML messages have to go through complex parsing
and validation before data is extracted. However, as
network devices become more powerful the process-
ing delays caused by XML messages becomes a less
relevant factor.
The added processing overhead generated by
adding compression to documents is very small,
therefore by using compression the gains in reduced
network traffic generated outweigh the losses in terms
of processing delays. In the near future we plan to ver-
ify the memory consumption levels at the PEP. This
can be a concerning factor because DOM parsers have
to reconstruct entire XML documents in memory in
order to process it.
Babiarz, J., Chan, K., and Baker, F. (2006). Configuration
Guidelines for DiffServ Service Classes. RFC 4594
Beller, A., Jamhour, E., and Pellenz, M. E. (2004). Defining
Reusable Business-Level QoS Policies for DiffServ.
In DSOM, pages 40–51.
Bernet, Y., Blake, S., Grossman, D., and Smith, A.
(2002). An Informal Management Model for Diffserv
Routers. RFC 3290 (Informational).
Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z., and
Weiss, W. (1998). An Architecture for Differentiated
Service. RFC 2475 (Informational). Updated by RFC
Bourdelon, J. and State, R. (2004). YENCA
Network Management Framework.
Chan, K., Sahita, R., Hahn, S., and McCloghrie, K. (2003).
Differentiated Services Quality of Service Policy In-
formation Base. RFC 3317 (Informational).
Chan, K., Seligson, J., Durham, D., Gai, S., McCloghrie,
K., Herzog, S., Reichmeyer, F., Yavatkar, R., and
Smith, A. (2001). COPS Usage for Policy Provision-
ing (COPS-PR). RFC 3084 (Proposed Standard).
Clemente, F. J. G., Pérez, G. M., and Gómez-Skarmeta,
A. F. (2005). An XML-Seamless Policy Based Man-
agement Framework. In MMM-ACNS, pages 418–
Enns, R. (2006). NETCONF Configuration Protocol. Tech-
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Conf Working Group.
Franco, T. F., Lima, W. Q., Silvestrin, G., Pereira, R. C.,
Almeida, M. J. B., Tarouco, L. M. R., Granville,
L. Z., Beller, A., Jamhour, E., and Fonseca, M.
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ington, DC, USA. IEEE Computer Society.
McCloghrie, K., Fine, M., Seligson, J., Chan, K., Hahn,
S., Sahita, R., Smith, A., and Reichmeyer, F. (2001).
Structure of Policy Provisioning Information (SPPI).
RFC 3159 (Proposed Standard).
Meier, W. (2006). eXist Version 1.0 - Open Source Native
XML Database. http://exist.sourceforge.net/.
Moore, B. (2003). Policy Core Information Model (PCIM)
Extensions. RFC 3460 (Proposed Standard).
Moore, B., Durham, D., Strassner, J., Westerinen, A., and
Weiss, W. (2004). Information Model for Describ-
ing Network Device QoS Datapath Mechanisms. RFC
3670 (Proposed Standard).
Moore, B., Ellesson, E., Strassner, J., and Westerinen, A.
(2001). Policy Core Information Model Version 1
Specification. RFC 3060 (Proposed Standard). Up-
dated by RFC 3460.
Schoenwaelder, J. (2003). Overview of the 2002 IAB Net-
work Management Workshop. RFC 3535 (Informa-
Schoenwaelder, J., Pras, A., and Martin-Flatin, J.-P. (2003).
On the Future of Internet Management Technologies.
IEEE Communications Magazine, 41(10):90–97.
Snir, Y., Ramberg, Y., Strassner, J., Cohen, R., and Moore,
B. (2003). Policy Quality of Service (QoS) Informa-
tion Model. RFC 3644 (Proposed Standard).
Yavatkar, R., Pendarakis, D., and Guerin, R. (2000). A
Framework for Policy-based Admission Control. RFC
2753 (Informational).
Youn, K. S. and Hong, C. S. (2003). A Network Manage-
ment Architecture Using XML-Based Policy Informa-
tion Base. In ICOIN, pages 876–885.