CDNI H. Song Internet-Draft Huawei Intended status: Standards Track July 09, 2012 Expires: January 10, 2013 A SLR (Service Level Requirements) based footprint for CDNI draft-song-cdni-slr-based-footprint-00 Abstract Footprint advertisement is a very important step for CDN interconnection and generates a lot of discussion. Actually, each CDN can serve the whole world if its surrogates are publicly reachable by IP addresses. But if a CDN does that, it can not satisfy the requirements from the applications. So CDNs deliver contents for applications, and the basic requirements should be from the applications, but there is rare discussion on service level requirements based footprint. This document is used to generate the discussion on this aspect. 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. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 10, 2013. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect Song Expires January 10, 2013 [Page 1] Internet-Draft CDNI footprint July 2012 to this document. Code Components extracted from this document must 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Why SLR Based Footprint . . . . . . . . . . . . . . . . . . . . 3 3. What are the parameters for SLR . . . . . . . . . . . . . . . . 4 3.1. Up-time . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. Average Response Time . . . . . . . . . . . . . . . . . . . 4 3.3. Hit Ratio . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.4. Capability . . . . . . . . . . . . . . . . . . . . . . . . 4 3.5. Throughput . . . . . . . . . . . . . . . . . . . . . . . . 4 3.6. Discussion . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Message Flows . . . . . . . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 7. Normative References . . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 5 Song Expires January 10, 2013 [Page 2] Internet-Draft CDNI footprint July 2012 1. 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]. 2. Why SLR Based Footprint Each CDN's footprint can be worldwide, if its surrogates' IP addresses are publicly reachable. However, not every CDN can serve the applications for worldwide distribution because it can not satisfy the serverice level required by those applications. So what an application basically needs is a CDN to satisfy its service level, and distribute the contents to certain areas. If a CDN or together with its downstream CDNs, cannot meet the SLR (service level requirements) in an area from an application, then we can say this upstream CDN is not competent for this content distribution task. This document specifies how the parameters of SLR impact a CDN's footprint. There is other draft [I-D.he-cdni-cap-info-advertising] mentioned capability advertisement, please note that capability advertisement is also very important and footprint is impacted by capability of a CDN. While each CDN serve many tasks concurrently, the dynamic resources that it can allocate is also variable at different time. The physical deployment area of a CDN might be small, but it can have larger footprint area where it can satisfy an application's SLR. The footprint area might be even larger than a CDN that has larger physical deployment area. Choosing SLR as the basis for footprint can avoid some CDN magnifying its service level and service area on purpose, and also make some other "small" but powerful CDN be treated with justness. We think that applications should participate in the CDN interconnection process implicitly, i.e. its requirements for service level should be transmitted between upstream and downstream CNDs (message protection is required due to the privacy). A downstream CDN should notify its capability information to its upstream CDN as well when notifying its footprint that satisfies certain SLR, which will allow a upstream CDN to choose multiple downstream CDN to fullfill a task even in a same area. In general, service level is the main driver for the definition of footprint, and applications do not care about the locations where a CDN's surrogates are deployed while it can satisfy its service requirements. And topologically, ALTO [I-D.ietf-alto-protocol] is used for the appropriate surrogate selection after the footprints are Song Expires January 10, 2013 [Page 3] Internet-Draft CDNI footprint July 2012 defined. And ALTO network map information can also be used for the footprint description to upstream CDN . 3. What are the parameters for SLR The general principal for SLR is fast, scalable, secure and reliable. But it needs detailed measurement metrics for it. Here we put the capability requirements as one parameter for SLR, as one upstream CDN can choose multiple downstream CDNs to satisfy an customer application's requirements. This section lists the possible parameters for SLR. However, this document is not going to define the specifics for the measurement methods. 3.1. Up-time Uptime is a measure of the time a machine has been up without any downtime. For a CDN system, it usually needs to guarantee a 100% up- time for system (not for each host). 3.2. Average Response Time This value is to refelct the average response time in normal network condition. This value impacts the footprint a lot. 3.3. Hit Ratio This is about the content availability. (TBD) 3.4. Capability Please refer other documents for the CDN capability advertisement in CDNI WG. 3.5. Throughput This parameter will also impact the footprint. If a CDN's available throughput is very big then it can serve more than its deployment area. 3.6. Discussion Not all parameters required for a certain service level are listed. Some parameters might impact a CDN's footprint, and some will not. Should all of them be conveyed in the same way among CDNs or just a portion of them that affect the footprint? Song Expires January 10, 2013 [Page 4] Internet-Draft CDNI footprint July 2012 4. Message Flows TBD. 5. Security Considerations TBD. 6. IANA Considerations There is no IANA consideration for this document. 7. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [I-D.he-cdni-cap-info-advertising] He, X., Dawkins, S., Chen, G., Zhang, Y., and W. Ni, "Capability Information Advertising for CDN Interconnection", draft-he-cdni-cap-info-advertising-01 (work in progress), March 2012. [I-D.seedorf-cdni-request-routing-alto] Seedorf, J., "CDNI Request Routing with ALTO", draft-seedorf-cdni-request-routing-alto-01 (work in progress), March 2012. [I-D.ietf-alto-protocol] Alimi, R., Penno, R., and Y. Yang, "ALTO Protocol", draft-ietf-alto-protocol-11 (work in progress), March 2012. Author's Address Haibin Song Huawei Email: haibin.song@huawei.com Song Expires January 10, 2013 [Page 5]