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. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. 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Code Components extracted from this document must Song & Lee Expires August 22, 2013 [Page 1] Internet-Draft I2AEX Feb 2013 include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. 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 Song & Lee Expires August 22, 2013 [Page 2] Internet-Draft I2AEX Feb 2013 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 Song & Lee Expires August 22, 2013 [Page 3] Internet-Draft I2AEX Feb 2013 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 Song & Lee Expires August 22, 2013 [Page 4] Internet-Draft I2AEX Feb 2013 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 Song & Lee Expires August 22, 2013 [Page 5] Internet-Draft I2AEX Feb 2013 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. Song & Lee Expires August 22, 2013 [Page 6] Internet-Draft I2AEX Feb 2013 Authors' Addresses Haibin Song Huawei Email: haibin.song@huawei.com Young Lee Huawei Email: leeyoung@huawei.com Song & Lee Expires August 22, 2013 [Page 7]