Image Processing Reference
In-Depth Information
8.4.1.1 Control Information Repository
The CIR is used to maintain the network topology and the resource statistics of the
related links, including the communication paths in a real-time manner. The network
topology and paths may be pre-defined, dynamically discovered or computed as in
[
19
]. Moreover, the links
resource statistics include the overall capacity of each
network interface, and the amount of bandwidth reserved and used in each CoS on
the interface [
19
]. Further, the CIR records the user
'
s sessions-to-CoS mapping along
with the related configuration parameters. These parameters include the QoS require-
ments of the session (e.g., bandwidth, delay, jitter and packets loss), the session ID, the
IDs of the flows that compose the session, the ID of the CoS to which the session
belongs, the flows
'
source and destination IDs (e.g., IP and Media Access Control
(MAC) addresses) and the ports IDs. Additional users
'
relevant profile information
such as billing and personalization parameters may also be stored in the CIR.
'
8.4.1.2 Admission and Resource Control
With the ARC component, the SDNC is able to control the access to the network,
which spans the coordination of the cooperative UEs within the network. The SDNC
achieves this by dynamically taking into account not only the incoming service
request QoS requirements (e.g., bandwidth) and the network resource availability
obtainable from the CIR database, but also the potential energy efficiency of the
adopted strategy. It is responsible for creating and managing the communication
paths inside the network. Hence, the ARC provides an interface to receive requests
and also to send control instructions to be enforced throughout the network. When-
ever there is a session request admission, termination or readjustment of the QoS
requirements of a running session, the relevant information (e.g., resource usage) is
updated in the CIR in real-time fashion. This is important to maintain a good
knowledge of the network resource conditions without undue probing signaling.
Another advantage, for example, is that the ARC can exploit the updated informa-
tion from the CIR to optimize control performance in terms of traffic load-balancing.
Moreover, the ARC implements the advanced resource over-reservation algorithm
introduced in [
19
,
23
], so session requests can be admitted, terminated or readjusted
without instant signaling or resource wastage in the network. Hence, upon exhaus-
tion of the over-reserved resource in a requested CoS on a path, the ARC can
re-compute new reservation parameters and trigger the reservation readjustment
among the CoSs on the path to prevent the wastage [
19
,
23
].
8.4.1.3 Management Information Base and Control Policies
Enforcement
The MIB and the CPE components enable network transport nodes (see Fig.
8.10
)
to carry out the basic control functions required in all network nodes. In particular,
