dynamic composition of virtual network functions in a cloud environment
TRANSCRIPT
Alma Mater Studiorum - Universita di Bologna
Dynamic composition of virtual network functions in cloudenviroments
SupervisorProf. Eng. Walter Cerroni
Assistant SupervisorsEng. Chiara Contoli
Eng. Giuliano Santandrea
Candidate
Francesco Foresta
3rd March 2015
Summary� Introduction
� Cloud Computing� Network Functions Virtualization (NFV)� Software Defined Networking (SDN)� OpenStack
� Case Study: Dynamic Service Chaining� Network Topology: L2 Level
� Implementation� Measurements
� Network Topology: L3 Level� Implementation
� Conclusions
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Context� In the last few years Telecommunications networks infrastructures
has been gradually modified� networks resources have been moved from the core to the edge of the
network itself, as close as possible to the end user (edge networks)� it’s expected that in the next future the core networks will be only a
combination of high-bandwidth connections between those edgenetworks
� In this kind of scenario, it will most likely take place the CloudComputing paradigm where network resources are offered from aprovider to a client as a service in a way which is similar toelectricity, telephones, gas, water.
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Cloud Computing
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Network Functions Virtualization (NFV)
The application of cloud computing to the edge networks lead up toorigin of NFV:� The original Internet paradigm is focused on packet forwarding
based on IP addresses, but in current IP networks packets areprocessed in intermediate nodes, called middle-boxes
� Each middle-box is tipically hardware, expensive and proprietary:� vendor lock-in problem: the client is dependant from the provider� Internet ossification: complexity of providing new services
� In 2012 a group part of the ETSI published a white paper: theproposal is to virtualize network functions on general purposehardware, simplifying middle-boxes
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Software Defined Networking (SDN)
All those approaches require a certain dinamicity and flexibility attraffic management level:� SDN: it’s a new approach to computer networking that allows
network administrators to manage network services throughabstraction of low-level functionality, standardised by Berkeleyand Stanford Universities in 2008� SDN architectures decouple network control and forwarding functions� It enables network control to become directly programmable and the
underlying infrastructure to be abstracted from applications andnetwork services
� The OpenFlow protocol lets to communicate network plane withthe data plane: it enables remote controllers to determine thepath of network packets through switches that made the network
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OpenStack
� It’s an Open Source joint project of Rackspace Cloud and NASA,assisted by more than 200 companies from the IT industry.
� It allows to manage cloud platforms: these are cluster of physicalmachines which contains some servers that will be offered as aservice to a client, in according to the IaaS(Infrastructure-as-a-Service) paradigm
� A user can create a virtual network infrastructure (VNI) composedof instances (implemented as virtual machines) and networksappliances (routers, firewalls, etc) in a simple and efficient way
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OpenStack: Components and abstractions
� OS is composed of some components: every component works ina specific area (networking, compute, identity, etc).
� Neutron (networking) defines these networks abstractions:� Network : an isolated L2 network segment;� Subnet : an IP address block on a certain network;� Port : an attachment point to a network;� Router : a gateway between subnets;� DHCP : a virtual appliance which gives IP addresses;� Security Group : a set of rules used as filters which implements a
firewall to the cloud platform level.
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How SDN and NFV co-operate
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Advantages e Disadvantages of NFV and SDN
Network cost reductions in hardwareNew business opportunitiesRemoved vendor lock-in problemMulti tenancyAdded flexibility in network functions and dynamismHigh scalabilityPossible loss of performance as the hardware moves fromspecialized to homogeneous� Likely only short term because of expected high innovation in
software
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Case study: Dynamic Service Chaining
� We want to realize a network scenario, at L2 and L3 Levels, whichimplements the NFV and SDN paradigms
� We are refering to a network services provider which offersconnectivity to two users: these contracted different agreements.There are a Residential and a Business Users; the second onerequires a better Qos than the first one.
� The suitable QoS is given by means of virtual network functionsimplementation: they elaborate user’s traffic while the steeringtakes place by means of an adequate programming of the SDNcontroller, applying service chaining mechanisms.
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How does it works
� The edge network containing the two user is built up usingOpenStack; outside its cluster there is the destination edgenetwork which can be reached via Virtual Router
� When a user starts to exchange traffic, initially it will be sent to aDeep Packet Inspector (in order to be classified) and to thedestination host
� After a bit of time traffic will be steered to the related networkfunction in order for the system to give the adequate QoS to eachuser:� WAN Accelerator (implemented by means of Trafficsqueezer) for the
BusUser� Traffic Shaper (realized with Traffic control) for the ResUser
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Topologies: L2 e L3
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L2 Level: topology realization
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L2 Level: Compute node OpenStack
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L2 Level: Network node OpenStack
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Implementative L2 Details
� The source edge network has been built up using the CLI of theOpenStack components (neutron, nova, glance) on Linux terminal
� The destination edge network has been realized in a external hostusing libvirt and the virsh command suite
� The SDN controller which has been programmed and used is theIl controller SDN programmato e utilizzato per la POX (writtenin Python): this allowed an efficient realization of the steeringoperations on br-int and br3� We implemented also some rules for eliminate problems like the ARP
Storming which affects the L2 scenario� The generated traffics of the two VMs have been realized using
the iperf tool, in the UDP mode
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L2 Measures
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L3 Level: topology realization
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Conclusions
� Experimental results have shown how an network approch like this(NFV, SDN, Cloud) can really rebuild the Telco area
� It really gives new possibilities to the network providers to createand manage new market offers with competitive prices, for theproviders themself and for the end-users; the easyprogrammability allows the provider to copy, migrate, destroy andmodificate network functions dynamically implemented
� Future Developments:� Use of the context-aware concept, for a greater involvement of the
SDN paradigm� Other steering experiments with different topologies types, also in
multi-tenant enviroment
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Thanks for the attention!
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