6tisch S. Anamalamudi Internet-Draft Huaiyin Institute of Technology Intended status: Standards Track M. Zhang Expires: August 6, 2017 AR. Sangi Huawei Technologies C. Perkins Futurewei S.V.R.Anand Indian Institute of Science February 2, 2017 Scheduling Function One (SF1) for hop-by-hop Scheduling in 6tisch Networks draft-satish-6tisch-6top-sf1-03 Abstract This document defines a 6top Scheduling Function called "Scheduling Function One" (SF1) to reserve, label and schedule the end-to-end resources hop-by-hop through the Distributed Resource Reservation Protocol(RSVP). SF1 uses the 6P signaling messages with a global TrackID to add or delete the cells in L2-bundles of isolated traffic flows. 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 6, 2017. Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. Anamalamudi, et al. Expires August 6, 2017 [Page 1] Internet-Draft draft-satish-6tisch-6top-sf1 February 2017 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 2. Operation of Scheduling Function One (SF1) . . . . . . . . . 3 2.1. Resource Reservation Protocol(RSVP) . . . . . . . . . . . 4 2.2. RSVP-PATH message . . . . . . . . . . . . . . . . . . . . 4 2.3. RSVP-RESV message . . . . . . . . . . . . . . . . . . . . 6 2.4. Reroute and Bandwidth Increase mechanism . . . . . . . . 10 2.5. Error Codes . . . . . . . . . . . . . . . . . . . . . . . 10 3. Scheduling Function Identifier . . . . . . . . . . . . . . . 10 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 6.1. References . . . . . . . . . . . . . . . . . . . . . . . 10 6.2. Informative References . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 1. Introduction Scheduling Function Zero (SF0) [I-D.ietf-6tisch-6top-sf0] enables on- the-fly cell scheduling (ADD/DELETE) between 1-hop neighbors for aggregated (best-effort) traffic flows. In other words, all the instances from nodeA to nodeB in Figure 1 are scheduled in a single L3-bundle (IP link). L3-bundle (Instance-1,Instance-2,...Instance-n) -------------------------------------------------> nodeA<------------------------------------------------- nodeB L3-bundle (Instance-1,Instance-2,...Instance-n) Figure 1: L3-bundle for aggregated traffic flows over 1-hop with SF0. Some applications (e.g. Industrial M2M) require end-to-end dedicated L2-bundles to support control/data streams for time-critical applications [I-D.ietf-detnet-use-cases]. For such applications, per-instance L2-bundles need to be scheduled hop-by-hop in between sender and receiver [I-D.ietf-6tisch-architecture]. In addition, cells in the scheduled end-to-end L2-bundles of each instance may Anamalamudi, et al. Expires August 6, 2017 [Page 2] Internet-Draft draft-satish-6tisch-6top-sf1 February 2017 have to be dynamically adapted for bursty time-critical traffic flows. To achieve this, an end-to-end track has to be installed with a global TrackID for each isolated instance. With 1-hop based SF0 cell scheduling, it is difficult to schedule dedicated end-to-end cells for isolated traffic flows. Moreover, global bandwidth estimation through Resource Reservation protocol is required for bandwidth allocation in multi-hop cell scheduling. This draft specifies a Scheduling Function One (SF1) to schedule end-to-end dedicated L2-bundles for each instance, and to dynamically adapt the cells in already scheduled L2-bundles through the RSVP protocol (see Figure 2). L2-bundle(Instance-1) L2-bundle(Instance-1) -----------------------> ------------------> <------------------------ <------------------- L2-bundle(Instance-1) L2-bundle(Instance-1) L2-bundle(Instance-2) L2-bundle(Instance-2) ----------------------> -----------------> Sender<-----------------------nodeB <----------------- Receiver L2-bundle(Instance-2) L2-bundle(Instance-2) . . . . L2-bundle(Instance-n) L2-bundle(Instance-n) -----------------------> --------------------> <------------------------ <-------------------- L2-bundle(Instance-n) L2-bundle(Instance-n) Figure 2: Dedicated L2-bundles for end-to-end isolated traffic flows with SF1 2. Operation of Scheduling Function One (SF1) With SF1, the Sender determines when to reserve end-to-end resources, support implicit label switching (GMPLS), schedule the labeled L2-bundles hop-by-hop, associate the global TrackID for labeled L2-bundles, and dynamically adapt the cells in an existing instance through RSVP(Resource Reservation Protocol). The following events may trigger the use of SF1: 1. If Sender has a outgoing bandwidth requirement for a new instance to transmit data to Receiver. 2. If Sender has a new outgoing bandwidth requirement for an existing instance to transmit data to Receiver. Anamalamudi, et al. Expires August 6, 2017 [Page 3] Internet-Draft draft-satish-6tisch-6top-sf1 February 2017 In both cases, distributed RSVP(explained in Section 2.1) is triggered to provide end-to-end resource reservations along with scheduling operations. 2.1. Resource Reservation Protocol(RSVP) In this specification, an end-to-end route path is assumed to be available, for instance by using reactive P2P-RPL (Storing or non- storing mode) routing. GMPLS signaling Resource Reservation Protocol (RSVP) with 6tisch scheduling capability is designed to label, reserve and schedule the resources hop-by-hop for isolated traffic flows. SF1 of the application sender will trigger the RSVP operation, whenever it has time critical traffic. RSVP has two messages, namely (1)RSVP-PATH message (Sender to Receiver) and (2) RSVP-RESV message (Receiver to Sender). 2.2. RSVP-PATH message The basic RSVP-PATH message [RFC2205] is used to carry the "Sender Traffic Specification" along with "characterization parameters" from sender to receiver. Since RSVP treat objects as opaque data, it is permissible to use another protocol element (e.g.,GMPLS, 6P, SF1) as an object in a RSVP-PATH message. The format of the PATH message that supports 6tisch scheduling capabilities (6P and SF1) is as follows: ::= [ ] [ [ | ] ... ] [ ] [ ] [ ] [ <6P OPERATION REQUEST> ] [ ] [ ] [ ] [ ... ] ::= [ ] [ ] The format of the Generalized Label Request Object in PATH message is: Anamalamudi, et al. Expires August 6, 2017 [Page 4] Internet-Draft draft-satish-6tisch-6top-sf1 February 2017 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length | Class-Num (19)| C-Type (4) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSP Enc. Type |Switching Type | G-PID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Generalized Label Request describes the requirement of communication characteristics to support the 6TiSCH-LSP being requested. Generalized Label Request object is set by the ingress node (6LR), transparently passed by transit nodes, and used by the egress node(6LR). 1. LSP Encoding Type (8 bits): Indicates the encoding of the LSP being requested. Value Type ----- ---- TBD Timeslot 2. Switching Type (8 bits):Indicates the type of switching that should be performed on a particular link. Value Type ----- ---- 100 Time-Division-Multiplex Capable (TDM) 3. G-PID (8 bits): An identifier of the payload carried by an LSP, i.e., an identifier of the client layer of that LSP. Value Type Technology ----- ---- ------ TBD Wireless Ethernet(802.15.4) 6TiSCH "SF1 OPERATION REQUEST" and "6P OPERATION REQUEST" are added in the PATH message to check for 6tisch scheduling capabilities within the intermediate nodes from sender to receiver. The "Timeslot Switching Capability" (TSC) is used as an implicit label to switch the cell at intermediate nodes [RFC3473]. "LABEL_REQUEST" in path message should be set to "Timeslot Switching Capability". The "RPLInstanceID" is added in the "SENDER_TEMPLATE" to create the Global TrackID during 6P transactions of RSVP-RESV messages. If an intermediate node does not support the TSC or "6P transactions" or "SF1 operation" then it MUST send a "PathErr" message back to application. Anamalamudi, et al. Expires August 6, 2017 [Page 5] Internet-Draft draft-satish-6tisch-6top-sf1 February 2017 2.3. RSVP-RESV message The basic RSVP-RESV messages [RFC2205] are transmitted upstream from receiver to sender to provide resource reservation as well as "Label Distribution". In this specification, hop-by-hop scheduling is extended to support both resource reservation and label distribution. The current specification is only defined for unicast point-to-point traffic flows, i.e., Fixed Filter (FF) reservation style. The format of the RESV message that supports 6tisch scheduling capabilities (6P and SF1) is as follows: ::= [ ] [ [ | ] ... ] [ ]