What's the Impact of Virtualization to ALTO?
draft-fu-alto-nfv-usecase-01

Internet Engineering Task Force                               Q. Fu, Ed.
Internet-Draft                                                    Z. Cao
Intended status: Informational                              China Mobile
Expires: August 17, 2014                                         H. Song
                                                                  Huawei
                                                            Febrary 2014

              What's the Impact of Virtualization to ALTO?
                      draft-fu-alto-nfv-usecase-01

Abstract

   This draft presents a use case of Application Layer Traffic
   Optimization (ALTO) with the emergence of Network Function
   Virtualization (NFV).  The Application-Layer Traffic Optimization
   (ALTO) Service provides network information (e.g., basic network
   location structure and preferences of network paths) with the goal of
   modifying network resource consumption patterns while maintaining or
   improving application performance.  The emerging Network Functions
   Virtualisation (NFV), as currently being in progress in ETSI NFV,
   leverages standard IT virtualisation technology to consolidate many
   network equipment types onto industry standard high volume servers,
   switches and storage.  The usecase presented in this draft discusses
   the impact of virtualization on the ALTO protocol.

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Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Impact of Virtualized Endpoints . . . . . . . . . . . . . . .   4
   4.  ALTO usecase with NFV . . . . . . . . . . . . . . . . . . . .   6
   5.  Interaction Architecture of ALTO and NFV  . . . . . . . . . .   6
   6.  Informative References  . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   This draft present a use case of Application Layer Traffic
   Optimization (ALTO) with the emergence of Network Function
   Virtualization (NFV).  The Application-Layer Traffic Optimization
   (ALTO) Service provides network information (e.g., basic network
   location structure and preferences of network paths) with the goal of
   modifying network resource consumption patterns while maintaining or
   improving application performance.  Typical deployment scenarios of
   ALTO include P2P and CDN, in which P2P tracker or CDN request router
   queries ALTO server for network map and cost map, in order to make
   decisions on which peer to select for content sharing.

   The emerging Network Functions Virtualisation (NFV), as currently
   being in progress in ETSI NFV, leverages standard IT virtualisation
   technology to consolidate many network equipment types onto industry
   standard high volume servers, switches and storage.  The NFV
   architecture in ETSI ongoing work includes the NFV MANO(Management
   and Orchestration), the OSS/BSS, the E/NMS (Element/Network
   Management System), the VNF (Virtualized Network Function) and the
   NFVI(Network Function Virtualization Infrastructure), as is shown in
   Figure 1.  The NFV MANO is composed of the VIM (Virtualized
   Infrastructure Manager), the NFV Orchestrator, and the VNF Manager.
   The VIM is responsible for controlling and managing the NFVI compute,
   storage and network resources, usually within one Operator's
   infrastructure sub-domain.  The NFV orchestrator is responsible for
   the lifecycle management of Network Services across the entire
   Operator's domain.  The VNF manager is responsible for the lifecycle

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   management of VNF instances.Interactions between NFV MANO, E/NMS, VNF
   and VNFI are beyond scope of this draft.

   With the trend of various network functions being virtualized, there
   will be impacts on cost and network characteristics of the service
   endpoints.  Under the ALTO architecture, we analyze the problems and
   the necessity of extending the ALTO protocols to faithfully reveal
   the network to the clients.  The central problem this draft would
   like to investigate is: what's the impact of virtualization to ALTO.

                                          +---------------------+
                                          |       NFV-MANO      |
                  +-----------+           |    +------------+   |
                  |  OSS/BSS  +-----------+----|Orchestrator|   |
                  +-----+-----+           |    +------+-----+   |
                        |                 |           |         |
                        |                 |    +------+-----+   |
                  +-----------+           |    |            |   |
                  |   E/NMS   |-----------+----+            |   |
                  +-----------+           |    |            |   |
                        |                 |    |    VNFM    |   |
                        |                 |    |            |   |
                  +-----+-----+           |    |            |   |
                  |    VNF    |-----------+----+            |   |
                  +-----------+           |    |            |   |
                        |                 |    +------+-----+   |
                        |                 |           |         |
                  +-----+-----+           |    +------+-----+   |
                  |   NFVI    |-----------+----|     VIM    |   |
                  +-----------+           |    +------------+   |
                                          +---------------------+

                    Figure 1: NFV Architecture in Brief

   This draft analyzes the impacts of virtualized endpoints to
   application layer traffic optimization and presents a usecase of ALTO
   in CDN and P2P network with the peers as a VNF(Virtualized Network
   Function). .

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   We use the following terms defined in [RFC5693].  Application, Peer,
   ALTO service, ALTO server, ALTO client, ALTO query, ALTO Reply.

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   And the following terms used in this document have their definitions
   from the NFV end to end architecture [NFVE2E].

   NFV: network function virtualization.  NFV technology uses the
   commodity servers to replace the dedicated hardware boxes for the
   network functions, for example, home gateway, enterprise access
   router, carrier grade NAT and etc.  So as to improve the re-
   usability, allow more vendors into the market, and reduce time to
   market.  NFV architecture includes a NFV controller (orchestrator) to
   manage the virtual network functions and the infrastructure
   resources.

   NF: A functional building block within an operator's network
   infrastructure, which has well-defined external interfaces and a
   well-defined functional behavior.  Note that the totality of all
   network functions constitutes the entire network and services
   infrastructure of an operator/service provider.  In practical terms,
   a Network Function nowadays is often a network node or physical
   appliance.

   VNF: virtual network function, an implementation of an executable
   software program that constitutes the whole or a part of an NF that
   can be deployed on a virtualization infrastructure.

   VM: virtual machines, a program and configuration of part of a host
   computer server.  Note that the Virtual Machine inherits the
   properties of its host computer server e.g. location, network
   interfaces.

   SLA: Service Layer Agreement.

3.  Impact of Virtualized Endpoints

   This section analyzes the impact of virtualization when application
   or service endpoints are deployed on virtualized infrastructure.

   It is generally believed that generic computing equipment is
   difficult to accomplish the same capability of specilized and
   dedicated equipment.  Operator network normally consists of many
   dedicated equipment, and the services running on them are not
   vitualized.  NFV initiatives investigate the use cases, architecture
   and requirements of moving network functions to the virtualized
   infrastructure.

   We analyze the impacts of virtualized endpoints to application layer
   traffic optimization for the following aspects.

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   1.  Performance.  The NFV framework is claimed to be able to
       instantiate and configure any given VNF over the underlying
       infrastructure so that the resulting VNF instance performance is
       conforming to the expressed requirement.  Using appropriate VNF
       configuration schemes
       [I-D.song-opsawg-virtual-network-function-config], the operator
       or service provider can express their performance requirement.
       From this point, it is the same as physical and non-virtualized
       service endpoints.  The difference is that the service assurance
       of virtualized endpoints is more difficult to ensure.

   2.  Portability.  Different from physical equipment, NFV framework is
       able to provide the capability to load, execute and move VNFs
       across different but standard mutlivendor environments, and have
       to support an interface to decouple VNF associated software
       instances from the underlying infrastructure.  Portability has
       impacts on the mobility and network location of the service
       points, which in return will impact the service point selection
       process and service continuity.

   3.  Elasticity.  The NFV framework is able to allow VNFs to be scaled
       with SLA requirements, on-demand scaling or automatically
       scaling.  With the elasticity capability, VNF endpoints
       capability with respect to computing and networking are dynamic.
       The ALTO discovery and selection process will be impact to
       reflect such dynamic information.

   4.  Resilience.  NFV framework provides the necessary mechanisms to
       allow VNF to be recreated after a failure.  In addition to OAM in
       traditional non-virtualized environment, the NFV MANO will manage
       the metrics such as packet loss rate, latency, delay variation of
       flows, maximum time to detect and recover from faults.  All of
       these information will be valuable to ALTO client.

   5.  Energy efficient.  Studies have indicated that NFV could
       potentially deliver up to 50% energy saving compared with
       traditional appliance based network infrastructure.  In service
       point selection, this could be a criteria when the service
       provider is interested in saving power.

   6.  Service assurance.  Dedicated carrier-grade devices normally have
       requirements like 99.999%, but the such high availability is
       still challenging for VNFs.  The ALTO server should be aware of
       the assurance level of these virtualized endpoints.

   7.  Network infrastructure maintenance.  The VNFs may be bridged and
       linked using the virtualized switches on the computing node.  The
       network layer performance and availability metrics are only

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       possible to collect when the OAM have established the tunnels to
       these virtual network infrastructure.  For example, normal PING
       can only reflect the physical computing node availability, but
       cannot reflect the VMs bridged using virual switchs and hidden
       with tunnel encapsulations.

4.  ALTO usecase with NFV

   The emergance of NFV means that some legacy devices which used to
   work on a physical server, now can be moved to a VM and work as a
   VNF.  Under such circumstance, the NFV MANO can act as a Dynamic
   Network Info provider for ALTO.

   The following paragraph will present a usecase of ALTO in CDN with
   NFV.  In the CDN network, the user agent first makes initial request
   to the Request Router.  The Request Router will first query the ALTO
   server for network and cost map to select an appropriate surrogate.
   The Request Router then responds to the UA with a redirection to the
   selected surrogate.  The UA then connects directly to the suggested
   surrogate to obtain the content.

   When a certain surrogate changes to a VNF and is managed by a NFV
   MANO, The NFV MANO can dynamically update the network and cost info
   of the surrogate to the ALTO server.  In the meantime, the NFV MANO
   should also keep ALTO server informed about the virtualized nature of
   the VNF surrogate, since its performance might be lower than physical
   devices.  In the migration stage of NFV, in which VNF and physical
   devices coexist in the network, ALTO server may consider the
   virtualized nature of VNF as a rating criteria that should inform the
   clients.  Clients may choose physical devices instead of VNF
   surrogates due to consideration of performance.

   In the P2P scenario, similar situations can also happen when peers
   become VNFs.  In this case, NFV MANO should also inform ALTO server
   about the virtualize nature of the VNF peers.  And P2P trackers can
   take such nature into consideration when selecting peers to obtain
   content.

5.  Interaction Architecture of ALTO and NFV

   A vertical architecture is proposed in this draft for ALTO and NFV
   interaction, in which NFV MANO is in responsible of info update to
   the ALTO server, as is shown in Figure 2.

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                            +---------------------+
                            |       NFV-MANO      |
         +-----------+      |    +------------+   |       +-------------+
         |  OSS/BSS  +------+----|Orchestrator|---+-------+ ALTO server |
         +-----+-----+      |    +------+-----+   |       +-------------+
               |            |           |         |
               |            |    +------+-----+   |
         +-----------+      |    |            |   |
         |   E/NMS   |------+----+            |   |
         +-----------+      |    |            |   |
               |            |    |    VNFM    |   |
               |            |    |            |   |
         +-----+-----+      |    |            |   |
         |    VNF    |------+----+            |   |
         +-----------+      |    |            |   |
               |            |    +------+-----+   |
               |            |           |         |
         +-----+-----+      |    +------+-----+   |
         |   NFVI    |------+----|     VIM    |   |
         +-----------+      |    +------------+   |
                            +---------------------+

Figure 2  ALTO and NFV interaction architecture

   In this architecture, NFV MANO can automatically update fine or
   coarse grained VNF info to the ALTO server timely.  The virtualized
   nature of the VNFs should be informed to the ALTO server by NFV MANO
   as a rating criteria.  In the meantime, details of VNF can be updated
   to the ALTO server by NFV MANO according to privacy privilege
   configured by the user.

   The information NFVO updates to the ALTO server for alto service
   discovery includes, but not limited to, the topology of the VNFs, the
   detail info of the network resource allocated to the VNF
   instances(such as the capacity, the available memory, the available
   CPU, and etc.), the lifecycle management info of VNFs, and etc..
   There is another draft talking about details of the these properties
   [I-D.wu-alto-endpoint-pid-properties].

6.  Informative References

   [I-D.song-opsawg-virtual-network-function-config]
              Song, H. and Z. Cao, "The Problems of Virtual Network
              Function Configuration", draft-song-opsawg-virtual-
              network-function-config-01 (work in progress), October
              2013.

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   [I-D.wu-alto-endpoint-pid-properties]
              Wu, Q. and Z. Cao, "Endpoint and PID Property Extension
              for virtualized endpoint and infrastructure", draft-wu-
              alto-endpoint-pid-properties-00 (work in progress),
              January 2014.

   [NFVE2E]   "Network Functions Virtualisation: End to End
              Architecture, http://docbox.etsi.org/ISG/NFV/70-DRAFT/0010
              /NFV-0010v016.zip", .

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5693]  Seedorf, J. and E. Burger, "Application-Layer Traffic
              Optimization (ALTO) Problem Statement", RFC 5693, October
              2009.

Authors' Addresses

   Qiao Fu (editor)
   China Mobile
   China
   China

   Email: fuqiao1@outlook.com

   Zhen Cao
   China Mobile
   Xuanwumenxi Ave. No.32
   Beijing  100053
   China

   Email: zehn.cao@gmail.com, caozhen@chinamobile.com

   Haibin Song
   Huawei

   Email: haibin.song@huawei.com

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