This document provides an overview of network function virtualization (NFV) infrastructure, including: - The NFV infrastructure architecture focuses on the compute, hypervisor, and infrastructure domains. The hypervisor domain provides resources and interfaces for software appliances running as virtual machines. - NFV infrastructure principles include defining functional blocks and their interfaces, and how network functions are divided between host functions and virtual network functions after virtualization. - The document discusses NFV infrastructure in relation to cloud computing models like SaaS, PaaS, and IaaS and covers NFV infrastructure domains, interfaces, and challenges related to performance.

1. Network Function Virtualisation -
Infrastructure Overview
Neelima Sharma

2. The content of this presentation is taken from the ETSI
NFV specifications and from various presentations
available on internet

3. What is covered…
 NFV Infrastructure – Overview
 NFV Infrastructure – Architecture
 NFV Infrastructure – NFVI and Cloud
Computing
 NFV Infrastructure – Domain architecture and
associated interfaces
 NFV Infrastructure – Compute Domain
 NFV Infrastructure – Hypervisor Domain
 NFV Infrastructure – Network Domain
 NFV Infrastructure – Challenges

4. NFV Infrastructure - Overview
 Below figure illustrate the section related to the Infrastructure

5. NFV Infrastructure - Overview
 NFV Infrastructure architecture is primarily concerned
 Compute Domain
 HyperVisor Domain
 Infrastructure Domain
 Hypervisor Domain provides
 Sufficient abstraction of the hardware for the portability of the Software
appliances
 Provide compute domain resources to the S/W appliances VM machines
 Provides management interfaces to the orchestration and management
system

6. NFV Infrastructure – Reference Architecture Framework

7. NFV Infrastructure – Architectural Principles of VNF
 System engineering approach of defining components as functional
block and their interconnection
 After network functions are virtualised

8. NFV Infrastructure – Architectural Principles of VNF
 Behavior of functional block is determined by
 Static transfer function of the functional blocks
 Dynamic state of the functional blocks
 Inputs it received in its interface
 Virtualization resulted in the following
 Division of functional block between a host function and VNF
 Creation of new container interface between the host function and the
VNF it is hosting
 Division of the interface between the two network functions which are
now virtualized between infrastructure interface and a virtualized
interface
 Relationship between VNF and host
 VNF is a configuration of the host function
 VNF is an abstract view of the host function when configured by VNF

9. NFV Infrastructure – Architectural Principles of VNF
 NFV architecture is defined using the following entities
 Host functions with their associated offered container interfaces and
associated infrastructure interfaces
 VNF with their associated used container interfaces and virtualized
interfaces

10. NFV Infrastructure – Management and Orchestration of
VNF
 Network functions have an interface ( North bound interface) to a
management and orchestration function

11. NFV Infrastructure – NFVI and Cloud Computing
 Five essentials characteristics of cloud services
 On demand self service
 Broad network access
 Resource pooling
 Rapid elasticity
 Measured service
 Service models impacting NFVI
 SaaS
VNF’s are software applications on cloud
VNF’s are executed according to a private cloud model
 Example is VNFaaS

12. NFV Infrastructure – NFVI and Cloud Computing
 PaaS
Service model consistent with deployment by network operators of services
 VNPaaS is a use case
 IaaS
Capability provided is the provisioning of compute, storage and
communication resources for the application to run
 Good use case is NFVIaaS

13. NFV Infrastructure – Domain Architecture and Associated
Interfaces

14. NFV Infrastructure – Domain Architecture and Associated
Interfaces
 VNF can be decomposed and made up from sub-parts which are
themselves VNF which are interconnected by infrastructure
 VNF’s can automatically request for management and orchestration
 Network interfaces must be decomposed between the infrastructure
protocols and the VNF protocols
 Infrastructure network is completely abstracted by the network infrastructure
container interface
 NFV infrastructure, applications and MANO are fully interoperable with the
existing OSS/BSS and carrier networks
 Below attached excel provides the details of the interfaces

15. NFV Infrastructure – Compute Domain
 Role of the Compute domain is to provide the interface to the network
infrastructure domain but does not support network connectivity
 Principal elements of the compute domain
 CPU
 Network Interface Controller (NIC)
 Storage
 Server
 Chasis
 Remote management
 Functional description of the compute domain needs to reference the
speed of execution

16. NFV Infrastructure – Compute Domain
 Primary characteristics of storage are :
 Latency in accessing a specific state held in storage
 Size of the storage
 Volatility or persistence of the storage
 Scope of Compute node includes
 CPU with storage
 Hardware for encryption and decryption
 Packet switching
 Accelerated packet forwarding

17. NFV Infrastructure – Hypervisor Domain
 Mediates the resources of the computer domain to the virtual
machines which includes :
 CPU
 NIC and so on …

18. NFV Infrastructure – Hypervisor Domain
 Forthcoming hardware improve the performance of VM’s which
includes
 multicore processors supporting multiple independent parallel threads of
execution
 system-on-chip processors that integrate multiple cores, DRAM
interfaces, network interfaces, storage,interfaces and hardware
acceleration for security, multicore processing, networking, storage and
application acceleration.
 specific CPU enhancements/instructions to control memory allocation
and direct access on I/O devices to VM memory allocations
 PCI-e bus enhancements, notably SR-IOV

19. NFV Infrastructure – Hypervisor Domain
 Specific features of hypervisor support for high performance NFV
VMs include
 exclusive allocation of whole CPU cores to VMs
 direct memory mapped polled drivers for VMs to directly access the
physical NICs using user mode instructions requiring no ‘context
switching’
 direct memory mapped polled drivers for interVM communications again
using user mode instructions requiring no ‘context switching
 vSwitch implementation as a high performance VM again using direct
memory mapping and user mode instructions requiring no ‘context
switching’

20. NFV Infrastructure – Hypervisor Domain Architecture
 Below figure illustrates the hypervisor domain architecture

21. NFV Infrastructure – Network Domain Reference point
Architecture
 Below figure illustrates the network domain reference point
architecture in the NFVI

22. NFV Infrastructure – Network Infrastructure Domain
 Roles of network domains includes :
 Communication channel between the VNFC’s of a distributed VNF
 Communication channel between different VNFs
 Communication channel between VNFs and their orchestration and
management
 Communication channel between components of the NFVI and their
orchestration and management
 Means of remote deployment of VNFCs
 Means of interconnection with the existing carrier network

23. NFV Infrastructure – Network Infrastructure Domain
 Essential elements needed for providing the connectivity with
domain:
 An infrastructure addressing scheme with address allocation and
management
 A routing process which can relate infrastructure addresses to routes
through the infrastructure network topology
 A bandwidth allocation process
 A set of OAM processes to verify reliability, availability and integrity of
connectivity services
 Requirement for bandwidth aspects requires :
 Permanently allocated, fully guaranteed bandwidth
 Respecting prioritization markings of the packet
 Guaranteed minimal latency variation

24. NFV Infrastructure – Network Infrastructure Domain
 Requirement for infrastructure network and VNF protocols to work
together
 Common Header
MAC header associated with NIC should be understood by both
 Transparent encapsulation
Carry the packet from the VNFC as a transparent payload and must add a
completely new header for transport by the infrastructure network
 Address binding
Mac addresses presented to the VNFC must be bound to infrastructure
network addresses

25. NFV Infrastructure – Challenges in Performance
 General recommendations to apply to network SW design
 SW requiring high performance should be partitioned in independent
modules running in different threads
 Modules should have independent memory structures in order to avoid
OS deadlocks
 Modules should communicate each other in pipeline structures,
minimising the use of the OS as an intermediate step
 OS interruptions should be reduced, if possible, to zero, due to its high
consumption of CPU cycles
 The use of OS network stacks should be avoided
 Network cards and other peripherals should communicate directly with
the modules through memory

26. NFV Infrastructure – Challenges in Interconnection of VNF