ALTO WG W. Roome Internet-Draft Alcatel-Lucent Intended status: Standards Track Y. Yang Expires: August 17, 2014 Yale February 13, 2014 PID Property Extension for ALTO Protocol draft-roome-alto-pid-properties-01 Abstract This document extends the Application-Layer Traffic Optimization (ALTO) Protocol [I-D.ietf-alto-protocol] by defining PID-based properties in much the same way that the original ALTO Protocol defines endpoint-based properties. 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 August 17, 2014. Copyright Notice Copyright (c) 2014 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 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. Roome & Yang Expires August 17, 2014 [Page 1] Internet-Draft PID Property Extension for ALTO Protocol February 2014 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. The Consistency and Inheritance Design Views . . . . . . . . 3 3. A Hierarchical View of a Network Map . . . . . . . . . . . . 3 3.1. Default Containment Hierarchy . . . . . . . . . . . . . . 3 3.2. Extension: Implicit Inheritance Via Nested PIDs . . . . . 4 4. Services . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. PID Properties Announcement . . . . . . . . . . . . . . . 4 4.2. Full PID Property Map Service . . . . . . . . . . . . . . 5 4.3. Filtered PID Property Map Service . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction A key abstraction introduced by the ALTO Protocol [I-D.ietf-alto-protocol] is PIDs (Provider-defined Identifiers), where each PID is defined as a name and a set of associated endpoint addresses. For IPv4/IPv6 networks, a PID's address set is defined by one or more endpoint address prefixes called CIDRs [RFC.4632]. This extension focuses on IPv4/IPv6 networks. An ALTO Server uses PIDs when defining one or more Network Maps, each of which is defined by a set of PIDs. Each Network Map defines a logical partition of a network address space, where similar endpoints are grouped in the same PID, specified by the addresses contained in the definition of the PID. An ALTO Server may publish multiple Network Maps, when there are multiple ways to partition networks. For example, one Network Map may partition endpoints according to geographical locations, and hence each PID defined in the Network Map represents the set of endpoints at a given location. Another Network Map may partition endpoints according to the capabilities (e.g., CDN delivery protocols such as HTTP or HTTPS) that the network can provide. In this case, each PID defined in the Network Map represents the endpoints with similar capabilities. A major missing component of the base ALTO Protocol is that the common properties are not specified. In particuar, in the base ALTO Protocol, each PID has only a name and a set of endpoint addresses. The objective of this document is to allow PIDs to have properties. Example PID properties include "country code", "continent code", "ISP", "lat/long bounding box", "endpoint type" (server farm, end users, cell data connections, etc). We identify use cases (e.g., VPN selection and CDN Capability Advertisement) where PID properties can provide value. Roome & Yang Expires August 17, 2014 [Page 2] Internet-Draft PID Property Extension for ALTO Protocol February 2014 2. The Consistency and Inheritance Design Views When we define PID properties, we follow a key consistency design guideline that PID properties should be consistent with and generalize the endpoint properties already defined in the base ALTO Protocol. Specifically, in the base ALTO Protocol, for each selected endpoint address, there can be a set of (prop-type, value) pairs associated with the endpoint address. These are called the endpoint properties of the selected endpoint. The ALTO Protocol allows an ALTO Client to obtain defined endpoint properties. Consider a given endpoint property p and all endpoints defined in a PID named pid1. If all of the endpoints have the same value v for p, then it is natural and consistent that when we define the value for p, as a PID property, the value should be v. For the more general case, let ip1.p denote the value of property p for endpoint ip1. Assume that pid1 consists of a set of n IP addresses, ip1, ip2, ..., ipn. Let pid1.p denote the value of property p for pid1. Then we can consider that pid1.p is from an aggreation function of ip1.p, ip2.p, ..., ipn.p. Example aggregation functions include average/ mean, mode, geo-center, union, bounding box, where meaningful aggreations depend on the specific property p. Complementing the bottom-up aggregation view, we also adopt a top- down inheritance view, by considering that when ip1 is in pid1, ip1.p inherits the value of pid1.p, if the value of ip1.p is not defined; otherwise, ip1.p overrides the value of pid1.p. The concept of inheritance is a simple, but powerful concept to reduce information redundancy. 3. A Hierarchical View of a Network Map 3.1. Default Containment Hierarchy A Network Map defined in the base ALTO Protocol can be considered as a default three-level hierarchy: with the highest (1st) level being a root, the next (2nd) level being the PIDs, and the lowest (3rd or leaf) level being the individual endpoint addresses. An issue that the base ALTO Protocol needs to resolve is that PID definitions can overlap, and hence to determine which PID an endpoint address belongs to. For example, consider a Network Map with two PIDs: PID1 is 10.0.0.0/8, and PID2 is 10.0.1.0/24. Then all addresses in PID2 are also in PID1. The base ALTO Protocol requires that an endpoint address be in one, and only one, PID, among the set of PIDs defined in the same Network Map. ALTO achieves this by specifying that if an address matches several CIRDs, the address is in the PID with the CIDR with the longest prefix. We refer to this PID as the home PID Roome & Yang Expires August 17, 2014 [Page 3] Internet-Draft PID Property Extension for ALTO Protocol February 2014 of the endpoint. Thus, for the example, 10.0.1.5 is in PID2, and 10.0.2.6 in in PID1. 3.2. Extension: Implicit Inheritance Via Nested PIDs In this document, we define PID properties for a more general containment hierarchy than the preceding default hierarchy. In particular, we consider nesting. That is, an ALTO server may define PID1, PID2 and PID3 such that all CIDRs defined in PID2 are also covered by the CIDRs in PID1; so are the CIDRs defined in PID3. Hence, we say that PID2 and PID3 can be considered "sub-PIDs" of PID1. To avoid potential issues of "multi-inheritance", for example, when PID2 is also a "sub-PID" of PID4, we consider only the case that the derived inheritance forms a tree. In other words, for the example that PID2 is sub-PID of both PID1 and PID4, then either PID1 is a sub-PID of PID4 or vice versa. Hence, we can say uniquely the direct parent of a PID. Future ALTO extensions may consider explicit definitions of nesting, for example, by specifying that PID1 consists of PID2 and PID2, without implicit derivation. With nesting, we define that PID2 and PID3 would inherit all properties of its ancestors, for example PID1, unless overriden in the sub-PIDs. For example, an ALTO server might define continent- level PIDs, as well as country-level or region-level sub-PIDs. If the ALTO server defines a "continent code" property for the continent-level PIDs, the country-level PIDs will automatically inherit that property. Such inheritance reduces information redundancy. 4. Services In the interests of simplicity, we will give an overview of the proposed services, rather than detailed descriptions. 4.1. PID Properties Announcement Given the consistency and inheritance design guideline, we require that PID Properties and Endpoint Properties use the same property name space. Such property names must be registered with IANA. To allow an ALTO Client to know the set of PID Properties assoicated with a PID Property Resource, we use the same approach as that of endpoint properties: announcement in IRD. An example is shown below. Roome & Yang Expires August 17, 2014 [Page 4] Internet-Draft PID Property Extension for ALTO Protocol February 2014 ... "resources" : { "my-default-network-map" : { "uri" : "http://alto.example.com/networkmap", "media-type" : "application/alto-networkmap+json" }, "endpoint-property" : { "uri" : "http://alto.example.com/endpointprop/lookup", "media-type" : "application/alto-endpointprop+json", "accepts" : "application/alto-endpointpropparams+json", "capabilities" : { "prop-types" : [ "my-default-network-map.pid", "priv:ietf-example-prop" ] }, }, "my-pid-property" : { "uri" : "http://alto.example.com/pidprop/netmap1/pidp1", "media-type" : "application/alto-pidprop+json", "uses" : ["my-default-network-map" ] "capabilities" : { "prop-types" : [ "country-code", "asn" ] }, } } 4.2. Full PID Property Map Service Analogous to ALTO's Full Cost Map Service, a Full PID Map Service returns properties defined for all PIDs in a Network Map. This is a GET request. The response message is similar to that of ALTO's Endpoint Property Service, but with PID names instead of endpoint addresses. The IRD entry for the service defines a "prop- types" capability with the names of the properties that this service returns, and specifies a "uses" attribute for the Network Map defining the PIDs. In the interests of limiting the response message size, the Full PID Property Map Service would NOT enumerate inherited property values. Thus if PID1 defines PROP1, and if PID2 is contained within PID1 and does not override the value for PROP1, then the response message gives a value for PROP1 in PID1, but not in PID2. In this case the client is expected to deduce the inheritance. That is feasible because the client has all information needed to do that. Roome & Yang Expires August 17, 2014 [Page 5] Internet-Draft PID Property Extension for ALTO Protocol February 2014 4.3. Filtered PID Property Map Service Analogous to ALTO's Filtered Cost Map Service, a Filtered PID Map Service returns a subset of the Full PID Property Map. The client specifies the desired property and PID names. This is a POST request. The response message is the same as for the Full PID Property Map Service. The request message is similar to the request message for ALTO's Endpoint Property Service, except with PID names instead of endpoint addresses. The IRD entry for the service defines a "prop-types" capability with the names of the properties this service returns, and specifies a "uses" attribute for the Network Map defining the PIDs. Unlike the Full Filtered PID Property Service, the Filtered PID Property Service would explicitly enumerate inherited property values. Thus if PID1 defines PROP1, and if PID2 is contained within PID1 and does not override the value for PROP1, then the response message includes PID1's value for PROP1 in PID2's properties. This is necessary because the Filtered PID Property Map response does not give the client enough information to deduce the inherited properties. For consistency, the Filtered PID Property Service would enumerate inherited properties for a PID even if the client also requested properties for all PIDs that containing that PID. 5. Security Considerations There are no security considerations relevant to this document. 6. IANA Considerations No actions are required from IANA as result of the publication of this document. 7. References [I-D.ietf-alto-protocol] Almi, R., Penno, R., and Y. Yang, "ALTO Protocol", draft- ietf-alto-protocol-20 (work in progress), October 2013. [RFC.4632] Fuller, V. and T. Li, "Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan", RFC 4632, BCP 122, August 2006. Roome & Yang Expires August 17, 2014 [Page 6] Internet-Draft PID Property Extension for ALTO Protocol February 2014 Authors' Addresses Wendy Roome Alcatel-Lucent Technologies/Bell Labs 600 Mountain Ave, Rm 3B-324 Murray Hill, NJ 07974 USA Phone: +1-908-582-7974 Email: w.roome@alcatel-lucent.com Y. Richard Yang Yale University 51 Prospect St. New Haven, CT USA Email: yry@cs.yale.edu Roome & Yang Expires August 17, 2014 [Page 7]