INTERNET-DRAFT Sami Boutros Intended Status: Standard Track Ankur Dubey VMware Reshad Rahman Cisco Expires: November 15, 2017 May 14, 2017 Service Redundancy using BFD draft-adubey-bfd-service-redundancy-00 Abstract In a data center, when multiple routing/service nodes are providing single active redundancy for a set of L2, L3 and/or L4-L7 services. Both non-revertive and revertive fail over modes are required for the services. This draft describes a method to achieve the non-revertive and revertive fail over modes for services using Bidirectional Forwarding Detection (BFD). Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Copyright (c) 2017 IETF Trust and the persons identified as the Dubey-Boutros Expires November 15, 2017 [Page 1] INTERNET DRAFT Service Redundancy using BFD May 14, 2017 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Solution Overview . . . . . . . . . . . . . . . . . . . . . . . 4 3 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Security Considerations . . . . . . . . . . . . . . . . . . . . 5 5 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5 Dubey-Boutros Expires November 15, 2017 [Page 2] INTERNET DRAFT Service Redundancy using BFD May 14, 2017 1 Introduction This document describes how can a group of service/routing nodes in a data center providing single active redundancy for multiple L2/L3 and/or L4/L7 services, can use BFD protocol to support non-revertive as well as revertive fail over mode. Typically, BFD is used between the group of service nodes to verify the connectivity as well as the aliveness of the service nodes. The assignment of which node in the group is the primary designated forwarder for a given service can be determined using a centralized or distributed control plane. The use of BFD will be to communicate the set of services that are being currently active on a given service node to the other service nodes. On a given node failure, for a given service the backup node will take over. If the service was configured to have a non-revertive fail over mode, then the backup node should continue to perform the service forwarding even after the primary node recovers and comes back up. In order to do that, the backup node MUST inform the primary node that it is currently active for the service. This is achieved through the extension we are proposing to the BFD protocol as will be described in the following sections. It is to be noted that for revertive fail over mode of operation, the primary node should be able to take over the active role from the backup node when the primary node goes back to an operational state. This can be as well communicated using the BFD session establishment between the primary node and the backup node. 1.1 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 RFC 2119 [RFC2119]. Dubey-Boutros Expires November 15, 2017 [Page 3] INTERNET DRAFT Service Redundancy using BFD May 14, 2017 2. Solution Overview +----------+ |Controller| +----------+ // | \ // | \ // | \ +-------+ +-------+ +-------+ |Node1 |-BFD-|Node2 |-BFD-|Node3 | +-------+ +-------+ +-------+ |--------------BFD--------| Figure 1: Figure 1 shows 3 routing nodes using BFD to implement the single active redundancy for revertive and non-revertive services. Multiple L2/L3 and/or L4/L7 services are offered in a data center by a set of routing/service nodes providing single active redundancy. The provisioning of the services can be done using a centralized control plane implemented in a controller or using a distributed dynamic control plane. Every L2/L3 and/or L4/L7 service is identified by a unique ID known across the routing/service nodes providing the services. A bitmap will be used to represent the services, where each service is represented by one bit in the bit map. All the service nodes MUST have the same mapping of the bit position to the service unique ID. The bitmap position and the unique service ID could be maintained by a network controller. The bitmap will be used in the payload of the BFD packets sent by the service node to indicate which service the node maintain an active status for. Service nodes providing single active redundancy will communicate using BFD this bitmap carried in the BFD control packet payload. When a backup service node takes over a service with a non-revertive fail over mode after primary node failure. The backup node once the BFD session comes up with the recovered primary node, will set the bit associated with this service in the bitmap payload carried in the BFD control packet sent to the primary node. Furthermore, the backup node will use a new Diag code in the BFD control packet to inform the primary node that it out-lived it and took over the set of non- preemptive services encoded in the bitmap of the BFD control packet payload. Dubey-Boutros Expires November 15, 2017 [Page 4] INTERNET DRAFT Service Redundancy using BFD May 14, 2017 The BFD control packet with the new Diag code and the bitmap will be sent after the BFD session came up in the BFD control packets for at least twice the detection multiplier count. Only the non-revertive services associated bits in the bitmap will be set by a service node acting as a backup for those services after a primary node failure recovery. Primary node upon receiving the BFD control packet with the bit set for the corresponding non-revertive service MUST not attempt to activate the service, but should remain in standby state for the service until the backup node that took over fails. Revertive services are assumed to revert back to the primary node after primary node recovers. Once the BFD session comes up between the primary and backup node, the backup node should stop forwarding for any revertive services. A node MUST start forwarding all revertive services for which it is configured as a primary once the BFD session comes up with the corresponding backup nodes. A node MUST stop forwarding for revertive services for which it is a backup once the BFD session comes up with the corresponding primary. 3 Acknowledgements 4 Security Considerations This document does not introduce any additional security constraints. 5 IANA Considerations IANA is requested to assign a new diag code from the "BFD Diagnostic Codes" Value BFD Diagnostic Code Name ----- ------------------------------------------------------------ 0xNN Out-lived and BitMap payload set with non-revertive services 6 References [RFC5880] D. Katz, D. Ward "Bidirectional Forwarding Detection (BFD)". Authors' Addresses Dubey-Boutros Expires November 15, 2017 [Page 5] INTERNET DRAFT Service Redundancy using BFD May 14, 2017 Sami Boutros VMware Email: sboutros@vmware.com Ankur Dubey VMware Email: adubey@vmware.com Reshad Rahman Cisco Email: rrahman@cisco.com Dubey-Boutros Expires November 15, 2017 [Page 6]