Page 589 - Cloud computing: From paradigm to operation

XaaS 3

Table 6-1 – Relationship between DaaS logical components and DaaS functions

DaaS logical components DaaS functions
This Recommendation
[ITU-T Y.3503]
Virtualization infrastructure support
Virtualization infrastructure
(see clause 7.1)
Connection manager
Virtual desktop connection and delivery
(see clause 7.2)
Virtual desktop delivery
Virtual desktop resource management
Resource pool
(see clause 7.3)
DaaS client support
DaaS client
(see clause 7.4)

7 DaaS functions

7.1 Virtualization infrastructure support

Virtualization infrastructure support functions provide the abilities to:
– offer abstracting hardware resources (see clause 7.1.1);
– allocate resources to a virtual desktop resource assignment function (see clause 7.1.2);
– improve the performance in terms of a DaaS platform (see clause 7.1.3);

– supply the interfaces to access the virtualization infrastructure (see clause 7.1.4).
7.1.1 Platform virtualization

Providing a separate virtual desktop environment for each DaaS user is a main role of the platform
virtualization function. This function:
– performs abstracting hardware resources in order to assign them to a virtual desktop efficiently;

NOTE – Abstracting hardware resources has different approaches, e.g., operating-system-level virtualization
and hypervisor which are configured to accommodate one or more virtual machines above hardware;
• operating-system-level virtualization is a virtualization method where the input/output (I/O)
management part of a base operating system (OS) allows for multiple isolated user space
instances, instead of just one. Such instances may look like a virtual desktop environment from
the point of view of its DaaS users. (E.g., container based approach);

• a hypervisor is a type of system software that allows multiple OSs to share a single hardware
host [ITU-T Y.3510]. It is classified into two types depending on the installation on a host
machine. In the one type, hypervisors are installed and run directly on the host machine's
hardware like an OS. The other type is described such a way that hypervisors are installed on
an existing operating system OS of the host machine and run just as other applications do.
– coordinates invocations on central processing unit (CPU), memory, disk, network and other
resources through the platform OS. Since the platform OS takes care of all the hardware, this
function supports the hardware compatibility;
– consolidates multiple platforms into the pool of physically separated hardware resources;
– isolates virtual desktops not to affect the operation of a platform itself or any other virtual desktops;
– constructs the multiple systems for DaaS such as server, storage and network to serve different DaaS
users.

7.1.2 Resource assignment
The resource assignment function:

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