Future Internet Chapter 5: Network Function Virtualization 5a: - - PowerPoint PPT Presentation

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Future Internet Chapter 5: Network Function Virtualization 5a: - - PowerPoint PPT Presentation

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Future Internet Chapter 5: Network Function Virtualization 5a: Basics Holger Karl Computer Networks Group Universitt Paderborn Overview Technical trends & motivation Reference architectures: ETSI, IETF Problems to solve

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Computer Networks Group Universität Paderborn

Future Internet Chapter 5: Network Function Virtualization 5a: Basics

Holger Karl

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Overview

  • Technical trends & motivation
  • Reference architectures: ETSI, IETF
  • Problems to solve
  • Existing projects
  • Conclusions

2 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Traditional network functionality

  • Provider networks not only

forward packets

  • Examples: Firewalls, deep

packet inspector, load balancer, content distribution, HTTP header enrichment functions, TCP optimizer, ...

  • By necessity distributed inside

the network

  • Traditionally implemented on

expensive, closed boxes

  • Physical network function,

"network appliance"

3 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Virtualize network functionality?

  • Network functions are just computing
  • Use commmon virtualization techniques to realize them?
  • Commercial off-the-shelf hardware
  • Somewhat optimized for networking performance
  • Software implementations: Virtual network function (VNF)

=> Network Function Virtualization (NFV)

  • Hope:
  • Improved CAPEX, OPEX (energy!)
  • Faster deployment
  • Flexible management

ETSI terminology

4 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Business options?

  • Business model: Opened up to external partners?
  • Not just the network operator
  • Escape route from "just a bit pipe"
  • NFVI as a Service: Infrastructure + Network as a Service
  • Target?
  • Business between network operators
  • But: Not just network functions per se
  • Even web servers, application servers, ... ?

5 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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FI - Ch 5a: Network Function Virtualization, Basics

Some use cases from ETSI

  • VNFaaS: Virtualize customer premise equipment into the

network

  • E.g., Enterprise access router, VPN termination, ...
  • Mobile Core/IMS functionality, mobile base stations
  • Virtualized home environment
  • Residential gateway (Internet, VoIP, firewall, NAT), set-top box for

media services, personal video recorder, ...

  • Virtualize content distribution networks
  • Netflix, Akamai, ... : dynamically provision web caches/streaming

proxies were needed

Network Functions Virtualisation; Use Cases. ESTI GS NFV 001.

6 SS 19, v 1.2

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Broadening the scope: Distributing data centers

  • Common rationale: Economy of scale
  • Build huge data centers to safe money
  • But results in only a few centers
  • Consequence: data centers far away from users
  • Fine for many applications
  • Critical for some: interactive, gaming, content distribution,

streaming, ...

  • Have some local functionality close to users?
  • Smaller centers, widely distributed
  • More expensive, more suitable?

7 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Distributed Cloud Computing

  • DCC pioneered in late 2000s, under different names
  • Distributed Cloud Computing
  • Carrier cloud
  • In-network cloud
  • Nano data centers
  • ….
  • Many commonalities with NFV
  • Different emphasis: end-user applications vs. network-oriented

features

  • Convergence? Open question …

8 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Overview

  • Technical trends & motivation
  • Reference architectures: ETSI, IETF
  • Problems to solve
  • Existing projects
  • Conclusions

9 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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First step: Infrastructure for Network Functions

  • Suppose network function virtualization takes place
  • Results in many small data centers in the network
  • In total: Network Function Virtualisation Infrastructure

(NFVI)

  • (Using ETSI terminology here, more details to come)

10 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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NFV Infrastructure

  • ETSI infrastructure definition
  • “Support deployment and execution of Virtualised Network

Functions”

  • “Totality of the hardware and software components which build up

the environment in which VNFs are deployed”

  • Leverage existing virtualization technology from computing
  • Enhance with network virtualization

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Compute domain Hypervisor domain Infrastructure network domain

Network Functions Virtualisation; Architectural Framework. ESTI GS NFV 002.

FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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NFVI vs. VNF

  • NFVI executes VNF: Separate description necessary

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Figure 4: Virtualisation of network function

IT-industy/ cloud interfaces

FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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NFVI: Recursion

  • Recursion allowed between VNF and Host Function!

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Server blade Hypervisor Virtual machine (VM) Operating system in VM VNF-implementing Application One specific function

Recall your basic

  • peration systems

class!

FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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NFVI & cloud technologies

  • Clouds provide basic technologies
  • Hypervisors to virtualize machines/operating systems
  • Virtual Ethernet switches (openVswitch, in particular)
  • With core functions, e.g., rapid elasticity, resource pooling
  • … as well as management interfaces
  • Typically, Web-based control of VM operations
  • Adopt business model of cloud computing for NFV?
  • On-demand self-service?
  • Pay-as-you-use? X-as-a-service?

14 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Towards a big-picture architecture

  • Which roles do we need?
  • Real stuff: computing, networks, external networks
  • Virtual stuff: (virtual) functions running “somewhere”, tied together

into virtual networks, realizing an application

  • Management and orchestration
  • Which interfaces do we need?
  • NFV-realized applications: run somewhere, be managed, talk to

networks

  • Virtualization interfaces for computing and networking
  • Mapping, management, orchestration interfaces

15 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Terminology

  • Virtual network function (VNF):
  • Software implementations of a network function
  • Packaged and executed inside a virtualisation container (e.g., VM,

Docker container)

  • Can be decomposed into smaller execution entities, called virtual

deployment units (VDU)

  • Not part of reference architecture
  • Executed on top of the NFVI.
  • Network service (NS): Multiple interconnected VNFs
  • Element manager (EM): responsible for functional

management of VNFs

  • Translates management requests from NFV MANO to (proprietary)

management interfaces of a specific VNF implementation

SS 19, v 1.2 FI - Ch 5a: Network Function Virtualization, Basics 16

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Terminology

  • NFV infrastructure (NFVI): environment on which VNF are

executed

  • Abstracts hardware resources into virtual resources.
  • Offer virtual compute/storage/networking resources
  • E.g., virtual subnets
  • Allows to run complex NS on top of it
  • NFV orchestrator (NFVO): end-to-end management and
  • rchestration of NS
  • Includes tasks like scaling, placing, and healing of NS/VNF
  • VNF manager (VNFM):Unlike NFVO, focuses on VNF

lifecycle management

  • E.g., instantiation, configuration, updating, scaling, and

termination

  • Multiple VNFMs can be deployed in an NFVO, allows to build VNF-

specific orchestration solutions

SS 19, v 1.2 FI - Ch 5a: Network Function Virtualization, Basics 17

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Terminology

  • Virtual infrastructure manager (VIM):
  • Manage virtualised resources provided by NFVI
  • Typically, NFVO/VNFM connect to multiple VIMs from different

vendors using internal abstraction models, often called VIM drivers

  • MANO = NFVI + NFVO + VIM
  • Service, VNF, and infrastructure description:
  • To deploy an NS/VNF, MANO systems needs description of those

artefacts.

  • Multiple standardised description approaches exist
  • Operation/business support system (OSS/BSS):

Usually, integrated with existing OSS/BSS of an operator

SS 19, v 1.2 FI - Ch 5a: Network Function Virtualization, Basics 18

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Overview architecture: ETSI reference architecture

SS 19, v 1.2 FI - Ch 5a: Network Function Virtualization, Basics 19

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ETSI reference architecture

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Mano framework VIM (e.g., OpenStack, VMWare, …

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Big-picture architecture

21 FI - Ch 5a: Network Function Virtualization, Basics

Network Functions Virtualisation; Infrastructure Overview. ESTI GS NFV-INF 001.

SS 19, v 1.2

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Big-picture architecture: Interfaces

22 FI - Ch 5a: Network Function Virtualization, Basics

Network Functions Virtualisation; Infrastructure Overview. ESTI GS NFV-INF 001.

SS 19, v 1.2

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ETSI Compute Domain

  • Computational and storage components, typically

commodity of-the-shelf (COTS)

  • CPU, network interface (NIC), storage, chassis, …
  • Acceleration hardware, e.g., en-/decryption
  • Combined into an industry-standard “server”

23 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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ETSI Hypervisor domain

  • Provide an abstract machine (on top of a real server) to

virtual network functions

  • … and to management/orchestration functions, if so desired

24 FI - Ch 5a: Network Function Virtualization, Basics

Network Functions Virtualisation; Infrastructure Overview. ESTI GS NFV-INF 001.

SS 19, v 1.2

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ETSI Infrastructure Network domain

  • Provide logical connectivity between
  • components of a virtual network function
  • different virtual network functions
  • virtual network functions and their context (management, …)
  • Abstracted into “virtual networks”
  • Infrastructure network must provide
  • At least one addressing scheme
  • Routing
  • Resource management
  • Guaranteed minimum datarate and maximum latency allocation

(ideally)

  • Or only prioritization

25 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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ETSI Infrastructure Network: Relation to VNFs

  • Common Header
  • Think of the infrastructure network as a layer 2 network underneath

the VNFs

  • VNF NICs can use MAC addresses to talk to each other!
  • Infrastructure network must be able to process that
  • Address binding
  • MAC addresses of virtual NICs not likely to be actual infrastructure

addresses

  • Necessitates a binding process between vNIC MAC and actual

infrastructure address

  • Transparent encapsulation
  • VNF packets carried as transparent payload
  • E.g., a Virtual LAN, but beware scalability concerns
  • Complicated by: multitude of infrastructure network technologies

26 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Interconnecting functions gets complicated

27 FI - Ch 5a: Network Function Virtualization, Basics

Network Functions Virtualisation; Infrastructure Overview. ESTI GS NFV-INF 001.

SS 19, v 1.2

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The Virtual Network Functions: High-level framework

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  • VNFs sitting on top of the NFVI
  • Helped along by management & orchestration functions

FI - Ch 5a: Network Function Virtualization, Basics

Network Functions Virtualisation; Architectural Framework. ESTI GS NFV 002.

SS 19, v 1.2

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Network Services as Forwarding Graphs of VNFs

  • In the end, we want to build services meaningful for a user
  • In the network, end-to-end
  • Examples: virtual private network, mobile voice, …
  • This goes beyond the purview of a single VNF
  • Goal: combine multiple VNFs into

a network service

  • Executed by the compute domain,

interconnected by the network infrastructure domain

  • Typically: Order matters!
  • A service needs several functions, working on a data flow in a

certain order

  • Expressed as a forwarding graph

29 FI - Ch 5a: Network Function Virtualization, Basics

Network Functions Virtualisation; Architectural Framework. ESTI GS NFV 002.

SS 19, v 1.2

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Forwarding graphs: Recursion allowed

  • A VNF inside a forwarding graph can be constructed using

a forwarding graph!

30 FI - Ch 5a: Network Function Virtualization, Basics

Network Functions Virtualisation; Architectural Framework. ESTI GS NFV 002.

SS 19, v 1.2

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Forwarding graphs

  • ETSI deliberately talks about forwarding graphs in general
  • Not just linear chains
  • IETF: service chains
  • Specification needs:
  • Which NFVs?
  • Traversed in which order?
  • How much load can one VNF handle?
  • At runtime:
  • Where does load come from?
  • Resource situation?

31 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Forwarding graphs: A specification proposal

  • Goal: Express relevant properties of a forwarding graph

succinctly

  • Oriented towards developers

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  • Observation:

sometimes, order does NOT matter

CDN DPI FW LB CDN DPI

FW LB FW LB FW FI - Ch 5a: Network Function Virtualization, Basics

  • S. Mehraghdam, H. Karl: Specification of Complex Structures in Distributed

Service Function Chaining Using a YANG Data Model, Netconf 2016..

SS 19, v 1.2

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Forwarding graphs: Specification examples

33 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Scaling effects – specification?

  • VNF instances can be dynamically created/destroyed

depending on load

  • Recall: cloud computing-like resource scaling
  • Question: Consequences for a function graph?
  • Due to: How much load can one VNF handle?
  • Simplify: normalized processing speed
  • Idea: Template specifications
  • Annotate edges in a function chain

by multiplicity: VNF instance can handle so many instances

  • f the previous stage

34 FI - Ch 5a: Network Function Virtualization, Basics

  • M. Keller, C. Robbert, H. Karl: Template Embedding: Using Application Architecture to Allocate Resources in

Distributed Clouds. In 7th International Conference on Utility and Cloud Computing (UCC). (2014)

SS 19, v 1.2

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IETF: Service Function Chaining

  • Essentially, very similar scope and basic approaches;

slightly different terminology, architecture details less evolved (or involved?)

  • Core working group: Network Working Group
  • Interesting aspects:
  • Explicit mention that service functions can exist at several layers of

an ISO/OSI stack; typically network layer up to application layer easy to imagine

  • Service Function Chain: partially ordered set of network functions,

along with copying, branching, … of the data flows

  • Consideration of unidirectional vs. bidirectional chains
  • E.g., DPI, firewalls might require both flow directions to pass through

same instance of the service functions

35 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Overview

  • Technical trends & motivation
  • Reference architectures: ETSI, IETF
  • Problems to solve
  • Existing projects
  • Conclusions

36 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Look at many functions

  • Isolated network functions the exception
  • Rather: data flows via several network functions
  • Simplest case: a chain
  • E.g.: A firewall, then a DPI, then a CDN
  • More sophisticated: arbitrary acyclic graph
  • Network function forwarding graph

37 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Placement

  • Given a forwarding graph: On which actual nodes to

execute which function?

  • Dealing with many graphs? Reuse functions? ...?

? ?

38 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Deployment

  • Suppose placement is solved
  • How to instantiate VMs, set up paths?
  • Software-Defined Networking!

39 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Scaling

  • Suppose monitoring tells us that KPIs not met
  • Throughput low, latency high, ...
  • Scale: Add virtual network functions, re-route, ...

40 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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ETSI reference architecture

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Placement & Scaling Deployment Monitoring Specification

FI - Ch 5a: Network Function Virtualization, Basics

Existing projects

SS 19, v 1.2

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Overview

  • Technical trends & motivation
  • Reference architectures: ETSI, IETF
  • Problems to solve
  • Existing projects
  • Conclusions

42 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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FI - Ch 5a: Network Function Virtualization, Basics

Open source activity: OpNFV

  • Initiative for an open-source NFVI/NFVI-Manager (including

Nf-Vi interface)

  • Public release available

https://www.opnfv.org/software/technical-overview

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Initial OpNFV focus

SS 19, v 1.2

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OpenSourceMano (OSM)

  • Open-source Management / Orchestration framework
  • https://osm.etsi.org
  • Current release:

https://osm.etsi.org/wikipub/index.php/OSM_Release_TWO

  • Aligned with ETSI reference architecture
  • UPB: member!

SS 19, v 1.2 FI - Ch 5a: Network Function Virtualization, Basics 44

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Overview

  • Technical trends & motivation
  • Reference architectures: ETSI, IETF
  • Problems to solve
  • Conclusions

45 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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Conclusions

  • Network operators pushing NFV a lot
  • Network providers (grudgingly?) give in
  • Distributed cloud computing so far still mostly academic
  • Use cases and business models not really settled
  • So far, heavy emphasis on network operator business
  • IT industry in general has not yet caught on
  • Think broader!?

46 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2

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References, further reading

  • European Telecommunication Standards Insitute (ETSI), Industrial

Study Group on Network Function Virtualization (ISG NFV), http://www.etsi.org/technologies-clusters/technologies/nfv

  • With various important white papers on reference architecture, use cases,

terminology (see “Specifications” tab on that web page)

  • Especially: https://portal.etsi.org/nfv/nfv_white_paper2.pdf
  • Vendor-specific white papers:
  • HP:

http://www.hp.com/hpinfo/newsroom/press_kits/2014/MWC/White_Paper_NFV .pdf,

  • Alcatel Lucent:

http://www.tmcnet.com/tmc/whitepapers/documents/whitepapers/2013/9377- network-functions-virtualization-challenges-solutions.pdf

  • Service chaining surveys
  • http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6702549
  • http://www.ewsdn.eu/previous/presentations/Presentations_2013/EWSDN-

2013-v10a.pdf

  • Papers for this chapter: Two mendeley groups
  • https://www.mendeley.com/groups/6764011/distributedcloudcomputing/
  • https://www.mendeley.com/groups/6763981/networkfunctionvirtualization/

47 FI - Ch 5a: Network Function Virtualization, Basics SS 19, v 1.2