CROWN: A Service Grid Middleware for e-Science - Grid Computing: Infrastructure, Service, and Applications - page 8

The node server provides all the generic functionalities when running a
service instance, such as SOAP message processing, service instance
management, instance/invoke lifecycle management, and notii cation
mechanisms. Based on the Globus Toolkit 4.0, the node server adds many
features such as remote and hot service deployment, resource status moni-
toring and reporting, logging, remote control, and management. By add-
ing security modules, the node server can provide features like PKI/
Kerberos-based authentication, i ne-gained authorization, trust manage-
ment, and automatic trust negotiation (ATN), which could guarantee
security and privacy effectively when resources are used by remote users
or cross-domain resources.

1.2.3.2 Resource Locating and Description Service (RLDS)

This is a distributed information service system for service registration
and discovery. Multiple RLDS instances use information exchange and
the topology maintenance protocol to build a hierarchical architecture
and overlay the network at runtime as needed to get better resource
management and service discovery performance.

1.2.3.3 CROWN Scheduler

This is a metascheduling service in CROWN that queues and schedules
users' jobs according to a set of predei ned strategies, interoperates with the
RLDS to get current service deployment information and job status, uses a
predei ned scheduling policy (random policy, load balancing policy, etc.) to
do the matchmaking, and performs the service invocation. The CROWN
scheduler supports two types of jobs: POSIX application invocation and
grid service invocation. A job submission description language ( JSDL) is
used to describe the QoS requirements and security demands of the job.

1.2.3.4 CROWN CommSec

This is a plug-in for the node server and a generic Web service to provide
basic security communication features such as building and verifying
certii cate chains. Administrators can edit the predei ned policy i le
according to complex security requirements to provide independent,
extensible, and feasible security solutions.

1.2.3.5 CROWN AuthzService

This is a generic service that uses an XACML-based authorization policy
description language and provides authorization decision and policy man-
agement capabilities. It supports the multigranularity access control pol-
icy and the domain access control policy.