LISP Working Group A. Rodriguez-Natal Internet-Draft Cisco Systems Updates: 6830 (if approved) A. Cabellos-Aparicio Intended status: Experimental Technical University of Catalonia Expires: October 6, 2017 V. Ermagan F. Maino Cisco Systems S. Barkai Hewlett Packard Enterprise April 4, 2017 MS-originated SMRs draft-rodrigueznatal-lisp-ms-smr-03 Abstract This document extends [RFC6830] to allow Map Servers to send SMR messages. This extension is intended to be used in some SDN deployments that use LISP as a southbound protocol with (P)ITRs that are compliant with [RFC6830]. In this use-case mapping updates do not come from ETRs, but rather from a centralized controller that pushes the updates directly to the Mapping System. In such deployments, Map Servers will benefit from having a mechanism to inform directly (P)ITRs about updates in the mappings they are serving. 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 October 6, 2017. Rodriguez-Natal, et al. Expires October 6, 2017 [Page 1] Internet-Draft MS-originated SMRs April 2017 Copyright Notice Copyright (c) 2017 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Map Server extension . . . . . . . . . . . . . . . . . . . . 3 3. Interoperability with legacy (P)ITRs . . . . . . . . . . . . 3 4. Deployment considerations . . . . . . . . . . . . . . . . . . 4 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. Normative References . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction The Locator/ID Separation Protocol (LISP) [RFC6830] splits current IP addresses in two different namespaces, Endpoint Identifiers (EIDs) and Routing Locators (RLOCs). LISP uses a map-and-encap approach that relies in two entities, the Mapping System and the Tunnel Routers. The Tunnel Routers are deployed at LISP sites edge points and perform encapsulation and decapsulation of LISP data packets. The Mapping System is a distributed database that stores and disseminates EID-RLOC bindings across different Map-Servers. LISP Tunnel Routers keep a cache of EID-RLOC mappings pulled from the Mapping System. There are several ways to keep this cache updated as described in [RFC6830]. Among them, the Solicit Map-Request (SMR) message allows to explicitly signal (P)ITRs to let them know that some of their cached mappings may be outdated. However, vanilla LISP as described in [RFC6830] only considers SMR messages to be sent by an ETR. This document extends [RFC6830] to cover the case where SMRs can be sent also by a Map Server (MS). Rodriguez-Natal, et al. Expires October 6, 2017 [Page 2] Internet-Draft MS-originated SMRs April 2017 This document introduces changes in the MS specification allowing them to send SMR messages, however it does not require any modification in the (P)ITRs. This document is backwards compatible and enables upgraded MS to interoperate via SMRs with legacy (P)ITRs that only implement [RFC6830]. 1.1. Requirements Language 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 RFC 2119 [RFC2119]. 2. Map Server extension This document enables MS to generate and send SMR messages towards (P)ITRs. SMRs originated in a MS follow the same format described in [RFC6830]. Besides the fact that they are sent from a MS, there is no difference between an SMR originated in an ETR and one originated in a MS. When a MS generates an SMR, it uses as source-EID the EID-prefix it wants the (P)ITR to send the SMR-invoked Map-Request for. The EID included in the EID-record field is the one belonging to the (P)ITR the MS sends the SMR towards. As source locator for the SMR message, the MS uses one of its available locators. This has implications in the processing of the SMR at the (P)ITR as described in Section 4 When the MS has to send an SMR is implementation specific. However, as specified in [RFC6830] and noted in Section 7, SMRs MUST be rate- limited. It must be noted as well that, as described in Section 3, a MS that sends an SMR may not receive the SMR-invoked Map-Request that the (P)ITR generates as response to the SMR. 3. Interoperability with legacy (P)ITRs This document introduces no changes in the specification of (P)ITRs and thus it is backwards compatible with legacy equipment only compliant with [RFC6830]. However, since SMRs were designed to be sent by ETRs, and legacy (P)ITRs expect to receive SMRs only from ETRs, the implications of sending SMRs from a MS are discussed in this section. As indicated in Section 2, the MS generates the SMR message using one of its locators as source locator. However, this locator will not be present in the Locator-Set cached for that EID-prefix at the (P)ITR. Following [RFC6830], upon receiving the SMR message, the (P)ITR will check if the source locator is in the Locator-Set cached for that EID-record. Since it is not, the (P)ITR will send the SMR-invoked Rodriguez-Natal, et al. Expires October 6, 2017 [Page 3] Internet-Draft MS-originated SMRs April 2017 Map-Request always to the Mapping System and never to the source locator of the SMR message. This means that a MS can not force an SMR-invoked Map-Request to be sent directly towards itself. However, it is possible that the Mapping System in use is instantiated (even partially) by the MS originator of the SMR. In that case, it may be that the SMR-invoked Map Request will eventually reach the MS, either directly or after being internally forwarded through the Mapping System. 4. Deployment considerations The extension defined in this document may be useful in scenarios where the MS wants to signal (P)ITRs about changes on mappings it is serving. For instance, when the MS is keeping track of the (P)ITRs that are requesting its mappings and wants to inform them intermediately whenever a mapping is updated. SDN deployments that use LISP as a southbound protocol are particularly suitable to take advantage of this extension. On the SDN scenario, mapping updates will unlikely come from ETRs, but rather from a centralized entity that pushes the updates directly to the Mapping System. In such deployments, Map Servers will benefit from having a mechanism to inform directly (P)ITRs about updates in the mappings they are serving. Due to scalability and security concerns, it is RECOMMENDED that this extension is only applied in intra-domain scenarios where all LISP devices are within a single administrative domain. To limit the impact of the extension and to ease its integration with the rest of LISP signaling and operation, it is RECOMMENDED that the MS only sends SMR messages for those mappings it is proxy-replying for. 5. Acknowledgments 6. IANA Considerations This memo includes no request to IANA. 7. Security Considerations As described in [RFC6830], the SMR messages and the SMR-invoked Map- Request MUST be rate-limited. This does not change with the extension proposed in this document. The (P)ITRs receiving SMRs from the MS will send Map-Request messages to the Mapping System to retrieve authoritative mappings. It is Rodriguez-Natal, et al. Expires October 6, 2017 [Page 4] Internet-Draft MS-originated SMRs April 2017 RECOMMENDED that the security mechanism described in [I-D.ietf-lisp-sec] and [I-D.ietf-lisp-ddt] are in place to secure the mapping retrieval and protect against unsolicited messages or hijacking attacks. 8. Normative References [I-D.ietf-lisp-ddt] Fuller, V., Lewis, D., Ermagan, V., Jain, A., and A. Smirnov, "LISP Delegated Database Tree", draft-ietf-lisp- ddt-09 (work in progress), January 2017. [I-D.ietf-lisp-sec] Maino, F., Ermagan, V., Cabellos-Aparicio, A., and D. Saucez, "LISP-Security (LISP-SEC)", draft-ietf-lisp-sec-12 (work in progress), November 2016. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The Locator/ID Separation Protocol (LISP)", RFC 6830, DOI 10.17487/RFC6830, January 2013, . Authors' Addresses Alberto Rodriguez-Natal Cisco Systems 170 Tasman Drive San Jose, CA USA Email: albrodr2@cisco.com Albert Cabellos-Aparicio Technical University of Catalonia Barcelona Spain Email: acabello@ac.upc.edu Rodriguez-Natal, et al. Expires October 6, 2017 [Page 5] Internet-Draft MS-originated SMRs April 2017 Vina Ermagan Cisco Systems 170 Tasman Drive San Jose, CA USA Email: vermagan@cisco.com Fabio Maino Cisco Systems 170 Tasman Drive San Jose, CA USA Email: fmaino@cisco.com Sharon Barkai Hewlett Packard Enterprise 3000 Hanover Street Palo Alto, CA USA Email: sharon.barkai@hpe.com Rodriguez-Natal, et al. Expires October 6, 2017 [Page 6]