Infrastructure to Application Information Exposure
draft-song-alto-i2rs-00

ALTO                                                             H. Song
Internet-Draft                                                    Y. Lee
Intended status: Informational                                    Huawei
Expires: August 22, 2013                                    Feb 18, 2013

           Infrastructure to Application Information Exposure
                        draft-song-alto-i2rs-00

Abstract

   This document describes the scenarios that applications can use the
   network layer especially the network routing system exposed
   information, so as to optimize application layer traffic.  The use
   cases in this document include the ISP broadband network (using P2P
   and CDN as examples) and the data center network.  And this document
   also describes which information should be collected for
   ALTO[I-D.ietf-alto-protocol] service, and eventually optimize the
   traffic.

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   This Internet-Draft will expire on August 22, 2013.

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   include Simplified BSD License text as described in Section 4.e of
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     3.1.  ISP network . . . . . . . . . . . . . . . . . . . . . . . . 3
     3.2.  Data Center Network . . . . . . . . . . . . . . . . . . . . 4
   4.  Open Discussion . . . . . . . . . . . . . . . . . . . . . . . . 6
   5.  Informative References  . . . . . . . . . . . . . . . . . . . . 6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 7

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1.  Introduction

   ALTO protocol is an interface provided to applications, to provide
   guidance when there are more than one application node providing the
   same service, through aggregated network map and cost map.  It
   usually aggregate network locations into PIDs, and assigns lower cost
   value for a PID pair that are topological close.  So when application
   node follows the advice from ALTO server to choose one resource
   provider within a PID that has lower cost from its own PID, with
   higher probability the application node can keep the content request
   and response traffic flow intra domain, which can reduce the
   suffering increasing interdomain traffic for ISPs, and avoid the
   congestion in the backbone network.  More factors for node selection
   can be considered, such as pricing, congestion, and etc.

   In order to achieve the above statements, it needs the underlying
   infrastructure to expose its topology information, malfunction node
   information, link status information, and pricing for path selection
   information to ALTO server, which will either be abstracted as the
   network map or as the impacting input factor of cost map.

2.  Terminology

   I2AEX: Infrastructure to Application Exposure.

   ALTO: application layer traffic optimization.

   IaaS: Infrastructure as a Service.

3.  Use Cases

3.1.  ISP network

   ISP broadband networks are consisted of interconnected autonomous
   systems.  They run BGP protocols between the boarder gateway routers,
   and run IGP protocols intra autonomous systems.  There are core
   routers, and access routers (BRAS) which fullfill the admission
   control through RADIUS servers, the access router connects to
   multiple aggregation switches.  And an aggregation switch connects to
   multiple DSLAMs or OLTs.  And the DSLAM or OLT connect to the home
   gateways or ONUs, which connect to the user devices.  [It's better to
   give a figure here.]

   The ISP network usually hide all its information to applications.
   But in the trend of big traffic use case, the main motivation is to
   reduce the backbone and interdomain traffic.  CDN and P2P are the two

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   target applications.  In a P2P application, the content requester
   requests contents from peers in the same swarm.  It may choose a peer
   that is far way with ignoring a peer that is topologically close to
   it.  Due to the topology ignorance, the application creates a lot
   unnecessary backbone and interdomain traffic.

   In another application of CDN, a popular resource usually is stored
   in multiple data centers.  Without the knowledge of the network
   topology, the CDN's DNS server redirects the content requester to a
   sub-optimal edge server, which is not always topolocially close to
   the content requester.  Even with measuring the round trip time
   between its edge servers and the requester's local DNS server, it can
   not get the accurate result because RTT is dynamic and user can
   specify its own DNS server.

   For the above two broadband network use cases, the infrastructure
   informaiton from the home to the access router does not help much.
   But more attendtion should be paid to the information from the access
   router to the routing system, which can provide important input for
   the ALTO maps.  An ALTO server needs the following information as
   input:

   o The network segments information.  Every access router manages one
   or more IP address pools, to be assigned to the users through DHCP or
   other ways.

   o The IP addresses of the interfaces of routers, and the routing
   table information(IGP or BGP).  This o information can help to
   construct the whole network topology.

   o The congestion status of the router interfaces, but this
   information could be reflected in the routing table change

   o Policy information, for example, one multi-homing AS prefers to use
   which AS to transit its traffic, including the pricing information.

   ALTO can use the collected informaiton above, to select a node
   topologically close, with low transit price, and also congestion link
   avoided.

3.2.  Data Center Network

   Infrastructure as a service(IaaS) is a way how the data center
   provides its services.  There are different kinds of resources in a
   data center, physical machines, virtual machines, switches,
   firewalls, computing power, storage space, and electronic power.
   There is proposal [I-D.lee-alto-ext-dc-resource] on collecting those
   kind of information, to make a key decision to allocate the

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   application request to an "optimal" Data Center location in which to
   host the application request.  Key constraints in this decision
   include resource availability (e.g., memory, storage, CPU, etc.), DC
   network cost, DC network resource constraints (e.g., bandwidth),
   structure constraints (e.g., Data Center power consumption) and
   others.

   Combined computing and network resource optimization is of value to
   both application owners and data center operators.  For example a
   data center operator with multiple buildings in a metropolitan area
   may also want to balance compute and network costs.

                               +--------------+
             Resource Request  | Application  |
                  -----------> | Orchestrator |
                               +-------+------+
                                       |
      +--------+                  +----+----+                 +--------+
      |        |                  |         |                 |        |
      |  DC 1  |<--------+------->|  ALTO   |<-------+------->|  DC 2  |
      |        |   ALTO-interface | Client  |  ALTO-interface |        |
      +--------+                  +---------+                 +--------+
                                      /|\
                                       |
                                       + ALTO-interface
                                       |
                                      \|/
                                  +---------+
                                  |         |
                                  |  DC 3   |
                                  |         |
                                  +---------+

   The ALTO server needs to collect the following information so as to
   provide this kind of service.

   o All switches' network capacity information

   o All physical servers' information(CPU, memory) in the data center

   o The storage space information in the data center

   o The physical links information

   o The virtual machines' information(CPU, memory) and its affinity

   o Pricing models

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   Based on the previous informaiton, ALTO server can provide the load
   balancing/traffic optimization informaiton to ALTO client for data
   centers, through map or ranking.

4.  Open Discussion

   In order to optimize the application traffic, network layer needs to
   provide necessary information to the according applications in the
   previous section, with a method (request/response, or subscription/
   notification) to make the underlying information changes be timely
   sent to the ALTO server.  This requires more interactions between the
   network layer and the application layer.  I2RS seems to consider more
   configuration use cases such like policy based routing, but what ALTO
   protocol needs is the part that discloses the network information.
   So there could be two ways to go forward.

   (1) Defining a new protocol for all the functions(configuration and
   disclosure) required by I2RS.  This protocol covers ALTO's south
   bound information requirements on network topology, with its one
   component.  But this protocol will be tremendously complicated.  It
   will be related and overlapped with many existing protocols, such
   like NetConf and YANG.

   (2) Defining the south bound interface for ALTO, to collect the
   infrastructure information, and bring the requirements discussion in
   I2RS, and identify the final scope, to avoid the overlap between
   different WGs(ALTO, NetConf, NetMod).  The protocol development will
   go to ALTO.

5.  Informative References

   [I-D.lee-alto-ext-dc-resource]
              Lee, Y., Bernstein, G., and D. Dhody, "ALTO Extensions for
              Collecting Data Center Resource Information",
              draft-lee-alto-ext-dc-resource-01 (work in progress),
              January 2013.

   [I-D.ietf-alto-protocol]
              Alimi, R., Penno, R., and Y. Yang, "ALTO Protocol",
              draft-ietf-alto-protocol-13 (work in progress),
              September 2012.

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

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Authors' Addresses

   Haibin Song
   Huawei

   Email: haibin.song@huawei.com

   Young Lee
   Huawei

   Email: leeyoung@huawei.com

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