Programmable Network Management based on the Web Services paradigm

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4 Νοε 2013 (πριν από 3 χρόνια και 7 μήνες)

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Programmable Network Management based on the Web Services
paradigm


DIMITRIS ALEXOPOULOS (*), JOHN SOLDATOS (**),


*
Electrical & Computer Eng. Dept., Computer Science Division,

National Technical University of Athens,

9 Heroon Polytechneiou Str, GR
-
15773
Zografou,

GREECE



**

Athens Information Technology,

19,5km Markopoulo Ave.,GR
-
19002, Peania, Attiki,

GREECE




Abstract:
Network Programmability is gradually gaining momentum in state of the art network and service
management implementations. Most of t
hese implementations rely on distributed programming models (such
as CORBA, RMI, DCOM) towards exporting programmable APIs that can be invoked from remote.
Nevertheless, very few implementations leverage the emerging W3C Web Services paradigm. In this pape
r we
describe the potential benefits from implementing programmable network management interfaces as a
collection of Web Services, and introduce a framework for delivering IEEE P1520 programmable interfaces
based on the Web Services standards. The paper re
views current network management models and their
limitations, along with relevant work targeting Web based programmability. Based on these reviews we
position the proposed framework, as a handy approach to boosting programmability in network and service
m
anagement.


Key
-
Words:
Web Services, Programmable Networks, Network Management, Web Based Management.



1. Introduction


Flexibility in network control and management is
nowadays a key requirement for network operators
and service providers. This i
s because network
operators and service providers need to be able to
deploy custom implementations of network control
and management algorithms, which are perfectly
tailored to their business strategies. Apart from
network control strategies telecom enterp
rises should
be capable of customizing their service management
schemes. Flexible service management allows for
deployment of new applications and subsequently
for generating new revenue streams.


Offering flexibility in network and service
management
is not a trivial task for a variety of
reasons. First, because the present and most probably
the future computer networks consist of
heterogeneous network equipment spanning a wide
range of different networking technologies and
vendors. Even worse, most ve
ndors do not provide
capabilities for custom implementation of network
control and service creation algorithms.
Standardization processes tackle with this
heterogeneity, and boost vendor interoperability;
nevertheless these processes are very slow and
cann
ot minimize time to market for network services
and applications.


To address these briefly mentioned issues that
combat flexibility in network control and
management systems the use of
programmable
network interfaces
(
PNI
) is gradually acknowledged
as

a prominent and efficient solution. Programmable
Network Interfaces rely on the implementation of an
application
-
programming interface

(
API
) enabling
control and management of individual network
elements (Element Management), as well as of
whole network c
ontrol algorithms and services
deployed on top of them. Based on APIs, the
standardization overhead is kept to a minimum,
which accelerates the respective deployment
procedures.


Several frameworks for designing and
implementing PNIs have been establish
ed in the
scope of research and industrial initiatives. Among
the prominent examples are
OPENSIG

with the
IEEE P1520
initiative [1],
TEMPEST
[15] and
Active Networks
(
ANTS
) [16]. We believe that
OPENSIG / P1520 deserves much attention since it
constitutes
a step towards PNI standardization. The
P1520

initiative, as shown in
Fig. 1
, is based on
developing multi


tiered programmable interfaces
that provide a flexible way of designing,
implementing and altering network management and
services.


Applicatio
ns that can be delivered through
programmable network interfaces in general and
IEEE P1520 in particular, cover areas such as
network control
(traffic engineering, call admission),
network management
(fault, configuration,
accounting, performance, security

-

FCAPS),
service
creation
and
management
. Network management is
a particularly important application given that most
current network management models lack essential
flexibility features. To be more specific, currently
network management in the Internet
is highly based
on
Simple Network Management Protocol
(
SNMP
),
which is simple but limited to individual devices or
restricted network segments, since it cannot scale for
large networks. Larger operator networks are usually
supported by the
Telecommunicatio
n Management
Networks

(
TMN
) architecture and relevant
supporting protocols. Acknowledging the need for
decentralizing network management task, industrial
and research efforts have focused on CORBA and
Java based management models that allow for
distributio
n network management paradigm.
Lightweight but less functional implementations of
decentralized network monitoring, control and
management are also achieved through the Web
based management paradigm [2].


Also, several efforts have also addressed servic
e
level management (e.g., the TINA architecture [17],
and other Java based models such as JAIN [13],
PARLAY [12]). It should be noted that TINA,
JAIN, PARLAY and CORBA based
implementations leverage programmable networks
concepts.
Thus, network managers ar
e more and
more considering programmable networks for
implementing network and service management.
Indeed, programmable networks applications can
overcome the limitations of legacy network and
service management models.



2. W3C Web Services for PN
Manage
ment


Current network programmability
implementations addressing network management
are mostly based on legacy distributed programming
models such as OMG’s
Common Object Request
Broker Agent

(
CORBA
), Microsoft’s
Distributed
Component Object Model

(
DCOM
)

and Sun’s
Remote Method Invocation

(
RMI
). To the best of
our knowledge there are very few implementations
that leverage the emerging Web services paradigm
for distributed applications.





Fig. 1


The P1520 Reference Model



Hence, in this paper, we concentrate on
implementing programmable network management
and service management applications based on the
Web Services distributed technology. We aim at
demonstrating that several characteristics of Web
Services are perfectly ta
ilored to supporting
implementations of PNIs. One of our objectives is to
provide a framework for implementing
programmable interfaces that comply with the IEEE
P1520 initiative and exporting them as W3C Web
Services.


Web Services constitute a W3C stan
dard for
distributed programming model, based on exchange
of
Simple Object Access Protocol
(
SOAP
) messages,
and description of services using the
Web Services
Description Language

(
WSDL
) [9]. The rationale
behind using Web Services in programmable
network
applications lies in the fact that they
provide a set of advantages for implementing
programmable network applications.


First, Web Services provide support for service
registration & discovery through the
Uni
versal
Description, Discovery
and

Integratio
n

technology
(
UDDI
) [10]. Thus, each service can be located
through the
UDDI Business Registry

(
UBR
)
depending on the management task at hand. Second,
Web Services are platform independent and enable
sophisticated system interoperability, since they are
in
voked over the standard HTTP protocol. In
addition, the HTTP based invocation bypasses all
obstacles in network management imposed by
proxies and firewalls. Furthermore, management
information and commands are implemented and
exchanged using XML. Thus, Web

Services’
implementations are more lightweight compared to
conventional CORBA and DCOM implementations.
It is also important that Web Services allow
programmable networks technology to be integrated
with network policy
-
based management. Indeed,
Web Servic
es could interact with policy services
through protocols like the widespread
Light
Directory Access Protocol

(
LDAP
), or the more
specialized
Common Open Policy Service

(
COPS
),
or even implement stand
-
alone network policies
using description, discovery and
assembly
techniques provided by the
UDDI

registry.


Using Web Services network management
applications can be implemented at discrete
layers/levels, based on the P1520 specification.
Element level management (the P1520
Physical
Element

and
Virtual Netw
ork Device

levels) could
be delivered as a Web Service. This delivery can
exploit existing work in the area of XML/MIB
mapping and exposing devices functionality through
an XML interface. Using XML interfaces and
through the
Simple Object Access Protocol

(
SOAP
)
[8] management of each element could be delivered
over the WWW. Thus, an element level API
allowing potential development of multi
-
device
network management functions based on a
distributed computing paradigm, is created as a
collection of Web Servic
es. This collection
constitutes the ‘
Element Level Web Services’
.


Referring to the network level management level
and the relevant
Network Generic Services

level of
the P1520 initiative, we use Web Services to
develop open, programmable interfaces. Ind
eed
tasks as routing, resource management or call
control could be addressed using a more complicate
set of Web Services (i.e. higher level API), which
could be based on the assembly of
element level
Web Services
. We call Web Services implementing
Network
Generic Services

management functions,

Network Generic Web Services
’.


Furthermore by exposing ‘
Network Generic Web
Services
’ functionality as another API, complex
network and service management algorithms could
be designed, developed and deployed in a
n easy and
timely fashion. Note that a Web Services
implementation provides direct support to Web
based management applications given that the
interface of the ubiquitous WWW Browser. Last but
not least, use of the WWW in the framework we
propose implies i
nheritance of Web Based
Management advantages, such as lightweight
implementation, distribution of management
functions or remote handling.



The following section, namely section 3,
introduces a framework for implementing
programmable network interface

for use within
network management applications. Section 4
discusses relevant work that can be exploited in any
implementation that follows the proposed
framework. Finally, Section 5 provides a brief yet
comprehensive set of conclusions.



3. A Framework f
or PN Management
using Web Services


The framework suggests that programmable
interfaces are implemented at various layers as
specified in IEEE P1520:
Element Level
Management
,
Network Level Management

and
Service Level Management.



3.1

Element Level
Management


At this level the main issue is to deliver the
network element’s management functionality as an
open
Application Programming Interface

(API). A
graphical representation of the proposed architecture
regarding the
Element Level Management

is s
hown
in
Fig. 2.



Fig. 2
-

Element Level Management



Starting from the
P1520

Physical Element

level
which represents the actual network element, a
vendor
-

specific implementation of a low level,
general purpose management protocol should
address task
s such as querying a node or altering it’s
state. Protocols like
Simple Network Management
Protocol

(SNMP),
Common Management
Information Protocol

(CMIP) or
General Switch
Management Protocol

(GSMP) could fit this
purpose, depending on the management inter
face
supported by the specific network device. From an
implementation perspective, frameworks as Sun’s
Java Management extension

(
JMX
) [6] or the open
source OpenNMS [7] can assist accessing low level
resources providing Java interface for protocols like
S
NMP.


We propose that network managers define an
abstract, vendor
-
independent representation of each
network element (e.g., switch, routers,
internetworking device, terminal), which could be
thought of as a generic
Management Information
Base

(
MIB
). To
comply with the Web Services
implementation, this Vendor
-
Independent MIB (VI
-
MIB) could be implemented as an XML


Schema
representation, containing the essential information
for monitoring and controlling the element node.
The status of the element can be

represented as an
XML document that conforms to the pre
-
mentioned
XML


Schema (VI
-

MIB), as long as the use of
XML for low
-
level resources description provides a
loosely coupled description of each element.


This XML
-

Schema with the correspondent X
ML
document, as well as collections of commands for
low level access to the network nodes will compose
the CCM


interface, as described in IEEE
P1520

[1]. The interface to those low level commands
(such as packet redirecting, getting and setting
system pr
operties etc.) should be implemented as an
open Application Programming Interface (API).
This constitutes the
Control API

(
C
-
API
) as
mentioned in
Fig. 2
. Such an API can substantiate a
Programmable Network Interface

(PNI), enabling
network administrators t
o develop modular, object
-
oriented management techniques. The applications
developed using the
C
-
API

will get information
regarding the relevant switch through the Schema


compliant XML instance, and will control the switch
through the CCM
-
interface.



The implementation of the
C
-
API
will be
delivered over the Web through the UDDI Business
Registry as a set of Web Services. This web
services’ API will compose the
Virtual Network
Devices
(Software Representation of network
elements) level described in th
e IEEE
P1520
.


3.2 Network Level Management


At this level we assume that each network
element’s functionality has been exposed as
illustrated in the previous paragraph. Thus, the
delivering of advanced network control algorithms
(admission control, rou
ting, resource management),
hinges on using available APIs to assemble more
sophisticated network and service management
functions. The proposed architecture for the
Network
Management Level

is graphically represented in
Fig.
3
.


As shown in
Fig. 3
, net
work level management is
implemented based on discovering and aggregating
Web Services deployed in the scope of Element
Level Management. Indeed, appropriate
combination of low
-
level functions such as packet
redirection could address tasks as resource
mana
gement or routing. The assembly of these
lower level functions into higher layer APIs should
be performed in an additional proxy or gateway
model.


A set of such functions dealing with network level
management issues will compose the
Network
Control API

-

NC
-
API

as mentioned in
Fig. 3

and
should also be deployed as a set of so
-
called
‘network level’ Web Services. This set of Web
Services could be thought of as the NGS level, as
referred in the IEEE P1520 initiative.



Fig. 3
-

Network Level Management


3.3 Service Level Management

Moving one layer above the NGS level,
Fig. 4

pictures the architecture we propose for
implementing service level management. Once
again Web Services’ dynamic finding and execution
enables our designing, implementing and deliver
ing
Value Added Services utilizing APIs delivered to
provide element and network level management
functionality (
C
-
API
and

NC
-
API
). These ‘service
level’ Web Services can be considered as IEEE
P1520

Value Added Services

level, and as is shown
in
Fig.

4

the
y accommodate needs of telecom
operators.



Fig. 4


Service Level Management



As stated in both network and service level
management multi


layered architecture of the IEEE
P1520

can take advantage of the fact that, in all
cases, higher layers could

make use of lower layers’
web services towards assembling more sophisticated
Web Services. An example of such a sophisticated
Web Service could be incorporating a network
policy implementation for element, network and
service level management. This integr
ation can be
realized in two different ways. A first option is to
establish a connection through a Web Service to a
static directory service, in order to gather
information about network management policies.
Another possibility is to leverage UDDI and Web
Service discovery for dynamic finding & executing
Network Management functions. Policies can be
implemented either through
Common Open Policy
Service

(
COPS
), or as other Web Services that
dynamically look up Network Level Web Services.
The pre
-
mentioned lo
okups could be achieved using
technologies like
Lightweight Directory Access
Protocol

(
LDAP
). As is also shown in
Fig. 3

and
4

access to the above mentioned network policy
implementation should have all layers of network
management.



4.

Relevant Work


A
lot of effort has been recently put on
implementing programmable network interfaces, and
developing network management applications on top
of them. To this end, several works have also
concentrated on devising techniques for vendor
independent representati
ons of the work. In this
paragraph we concentrate on Web based
architectures and implementations, which are
pertinent to our approach for implementing Network
management as web services. We also underline
cases where this relevant work could be reused in
the scope of our framework.


The
Parlay

working group has released Web
Services interfaces to the existing
Parlay/OSA

API
[12]. In this way telecom business can use
Parlay/OSA API through the Web Services
paradigm in order to provide an
Enterprise
Appli
cation Integration

(
EAI
) infrastructure
technology (
Fig. 5
).


The OpenNMS [7] project provides an open API;
based on Sun’s Java programming language, which
exposes low
-
level network management functions
from protocols like SNMP to a higher, more
abstra
ct level. This open API can be used in the
scope of our framework towards interfacing to the
low level capabilities of network elements.


A commercial management framework named
WebNMS developed by AdventNet Inc. is based on
the OPENSIG model. This fram
ework models
network elements using XML, CORBA, SNMP and
other technologies in the back
-
end and provides a
Web based network management system. Such an
approach is pertinent to our framework as far as
abstract modeling of network elements, finally
delivere
d over the WWW, is concerned.


Closely related to our framework’s need for
abstract modeling of network elements is the XML
and XML schema description of network elements
used in the scope of the project “XML based
Management Interface for SNMP Enabled
Devices”
undertaken from the
Avaya Labs Research

team
[19]. This modeling approach creates an XML
Schema definition of the element’s SNMP interface,
and uses XML to retrieve and modify device
information from the device’s MIB.


Another implementation of

network
programmability for network management has been
carried out by Intel Corporation, which developed
Phoenix Framework

that enables service
management over “
active devices


[19]. Those
active devices are devices in the network
infrastructure (routers
, switches etc.) that support
the
Phoenix Framework

and can be managed from
the Phoenix’s console


the
proactive console
. The
whole architecture is based upon Sun’s Java
programming language and consequently issues like
scalability, extensibility and secu
rity are handled
with Java Technologies such as the
Remote Method
Invocation

(
RMI
). The whole concept is similar to
our framework’s concepts except for the fact that it
relies on RMI instead of W3C web services.



5.

Conclusion
-

Future Work


Since Network

Programmability is a prominent
solution to providing open and flexible management
of networks and related services, programmable
implementations are proliferating. Most of these
implementations are based on legacy distributed
programming models, such as C
ORBA, RMI and
DCOM. Next generation implementations should
consider the emerging Web Services paradigm.
Several groups working on open API for network
and service management (e.g. Parlay) are already
focusing on web service implementations. In this
paper w
e have also contributed a framework for
delivering network and service management APIs as
Web Services. The framework follows the IEEE
P1520, and is fairly general in the sense that is
targets all possible networking infrastructures. The
framework attempts

to exploit all the beneficial
aspects of Web Services, including registration,
discovery and assembly of services.


As a next step to this work we intend to take into
account this framework in order to implement an
open API as a set of Web Services on

top of an
experimental network. Given that we have readily
available implementations of such APIs based on
Java RMI and Intelligent Agents [3,4], we believe
that this implementation will demonstrate the
benefits of the Web Services paradigm, as far as the

delivery of programming interfaces is concerned.
Also, we will use these web services in order to
build a web based management application, thus
revealing the ease of such an implementation in
contrast to traditional approaches.


References:

[1]

J. Biswas, A.

Lazar, S. Mahjoub, L.
-
F. Pau, M.
Suzuki, S. Torstensson, W. Wang, S. Weinstein,
“The IEEE P1520 Standards Initiative for
Programmable Network Interfaces”, IEEE
Communications Magazine, October 1998, pp.
64
-
71.

[2]

E. Vayias, J. Soldatos, N. Mitrou, K.
Kontova
ssilis, G. Kormentzas, “Managing
Networks over the Web: Classification of
Approaches and an Implementation” , Proc. of
the International Conference on
Telecommunications, ICT '98 , Chalkidiki,
Greece, June 1998, vol. IV, pp.451
-
456.

[3]

J.Soldatos, G.Kormentza
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Kontovasilis, N.Mitrou, "An Intelligent Agents
-
Based Prototype Implementation of an Open
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[4]

Han
sen, M., Jensen, P., Soldatos, J., Vayias, E.,
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-
level control of network elements from an
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-
0904188647, pp. 23
-
30, 1999.

[5]

Danny Raz, Yuval Shavitt: “Active Networks
for Efficient Distributed Network M
anagement”.
IEEE Communications Magazine, 38(3), March
2000, pp. 138

143.

[6]

Java Management eXtension (JMX):

http://java.sun.com/products/JavaManagement/

[7]

OpenNMS documentation:

http://www.opennms.org/users/docs/

[8]

W3C SOAP Specification:

http://www.w3.org/TR/SOAP

[9]

W3C WSDL Specification:

http://www.w3.org/TR/WSDL

[10]

UDDI Specifications:

http://www.uddi.org/specifications

[11]

W3C XML Schema Specification:

http://www.w3.org/TR/xmlschema
-
1/

http://www.w3.org/TR/xmlschema
-
2/

[12]

Parlay framework:
http://www.parlay.org/

[13]

JAIN framework:

http://java.sun.com/products/jain/overvie
w.html

[14]

Parlay Web Services:

http://www.parlay.org/specs/library/index.asp

[15]

Van der Merwe, J.E., Rooney, S., Leslie,
I.M. and Crosby, S.A., "The Tempest
-

A
Practical Framework for Network
Prog
rammability", IEEE Network, November
1997.

[16]

ANTS framework:
http://www.cs.washington.edu/research/networki
ng/ants/

[17]

TINA framework:
http://www.tina
c.com/


[18]

Avaya Labs Research, XML based
Management For SNMP Enabled Devices:
http://www.research.avayalabs.com/user/mazum
/Projects/XML/

[19]

Intel Corp.,
Phoenix Framework
:

http://www.intel.com/technology/itj/q31999/
pdf/phoenix.pdf