Page 638 - Cloud computing: From paradigm to operation

3 XaaS

between CSC and particular data centre. The XaaS CSP acting alone is not able to impact
network performance without interaction with NaaS CSP.
As a solution to guarantee end-to-end service quality, bandwidth reservations can be
applied in the network between the CSU and the data centre. This allows the guarantee of
certain network performance and can be a basis for end-to-end SLA contract for the service
between a CSU and the XaaS CSP. To fulfil these needs, XaaS CSP interacts with NaaS CSP.
NaaS CSP can be any actor that has the ability to offer connectivity between XaaS CSP and
the CSC, to which CSU belongs.
Roles CSU, CSC, CSP
Figure
(optional)

Pre-conditions – XaaS CSP has no impact on connectivity parameters between the service and the CSU.
(optional)
Post-conditions – XaaS CSP offers end-to-end service quality or SLA to the CSC, on the basis of
(optional) cooperation with NaaS CSP.
Derived – Seamless and end-to-end solution of bandwidth allocation (refer to clause 9.6)
requirements – Symmetric or asymmetric capacity (refer to clause 9.7)

II.4.2.4 NaaS connectivity use case for optimized traffic engineering

Title NaaS connectivity use case for optimized traffic engineering
Description The CSP provides network connectivity services to a CSC in order for the CSC to inter-
connect its own multiple geographically distributed data centres. With the increase of
cloud services deployed over the CSC's data centres, more and more traffic, e.g., for data
mirroring, redundancy, database synchronization, VM migration, active-active storage
replication, is traversing the CSP's backbone network due to the CSC's increasing
distributed services.
Currently, CSP typically provides the CSC with static connectivity services resulting in either
over-provisioned, under-utilized service capacity or under-provisioned, capacity-capped
services.
In order to make a more efficient use of its connectivity resources, a solution for the CSP is
to support a central decision-making function for the backbone traffic engineering. At the
minimum, such solution has to coexist with other legacy network solutions used by the CSP
for the support of other services.
Roles CSC, CSP

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