ALTO WG LM. Contreras Internet-Draft Telefonica Intended status: Informational July 13, 2020 Expires: January 14, 2021 Extending ALTO by using BGP Communities draft-contreras-alto-bgp-communities-00 Abstract This memo introduces the proposal of extending ALTO by using BGP Communities as PIDs. 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 https://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 14, 2021. Copyright Notice Copyright (c) 2020 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 (https://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. Contreras Expires January 14, 2021 [Page 1] Internet-Draft Extending ALTO by using BGP Communities July 2020 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. BGP Communities . . . . . . . . . . . . . . . . . . . . . . . 2 3. Extending ALTO with BGP communities . . . . . . . . . . . . . 3 4. BGP Community representation in ALTO . . . . . . . . . . . . 3 5. Security Considerations . . . . . . . . . . . . . . . . . . . 3 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 3 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction The Provider-defined Identifiers (PIDs) in the ALTO protocol [RFC7285] provide an indirect and network-agnostic way to specify an aggregation of network endpoints, that grouped creates a network map. Network end-points sharing a common PID are expected to receive similar treatment on the decisions assisted by ALTO. With the same idea of grouping of destinations, the concept of BGP Communities [RFC1997] was developed to apply a common routing decision to a number of destinations based on the identity of a group. Since BGP communities are widely configured in real operational networks, this document propose an extension to [RFC7285] by defining a new type of PID based on the BGP community concept. 2. BGP Communities A BGP Community is a BGP attribute which is used to group destinations The BGP Communities are represented as an integer number of 32 bit. It is typically written as the combination of two integer numbers of 16 bit separated by colon. The first number is usually the Autonomous System (AS) number, while the second one is determined by the service provider according to some internal logic. The IP prefixes can be part of distinct BGP Communities, with different purposes, typically for influencing the traffic reaching the particular prefizes of a community. The BGP Community attribute is useful for applying polcies of applicability to a certain set of prefixes, grouped as a community for some reason at the criteria of the service provider. Contreras Expires January 14, 2021 [Page 2] Internet-Draft Extending ALTO by using BGP Communities July 2020 3. Extending ALTO with BGP communities Network operators use extensively BGP Communities as a mean of putting together some destinations (i.e., IP prefixes) for different purposes Traditionally they are used by administratively-defined filters for applying policies, thus Influencing the behavior of the traffic towards the associated destinations. On the other hand, the ALTO protocol based on IP prefixes. When cosnidering queries to IP prefixes, it could be the case that those queries apply for IP addresses associated to the same topological element. This is for instance the case of aggregations node in the Network (such as BNG or PGW for example) which have associated a number of IP prefixes (that can evolve along the time). The same response will be obtained from ALTO server for all the prefixes associated with such a node since the topological information is essentially the same. For assisting on an efficient usage of ALTO resources in this kind of situations, the usage of BGP Communities can simplify the process by reducing the number of queries to ALTO server, but also by smoothly absorbing the modification of prefixes for a given aggregation node. 4. BGP Community representation in ALTO To be done. 5. Security Considerations To be done. 6. IANA Considerations This draft does not include any IANA considerations 7. References [RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, . [RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S., Previdi, S., Roome, W., Shalunov, S., and R. Woundy, "Application-Layer Traffic Optimization (ALTO) Protocol", RFC 7285, DOI 10.17487/RFC7285, September 2014, . Contreras Expires January 14, 2021 [Page 3] Internet-Draft Extending ALTO by using BGP Communities July 2020 Author's Address Luis M. Contreras Telefonica Ronda de la Comunicacion, s/n Sur-3 building, 3rd floor Madrid 28050 Spain Email: luismiguel.contrerasmurillo@telefonica.com URI: http://lmcontreras.com/ Contreras Expires January 14, 2021 [Page 4]