SFC WG T. Ao Internet-Draft ZTE Corporation Intended status: Standards Track G. Mirsky Expires: December 31, 2017 ZTE Corp. Z. Chen China Telecom June 29, 2017 SFC OAM for path consistency draft-ao-sfc-oam-path-consistency-00 Abstract Service Function Chain(SFC) defines an ordered set of service functions(SFs) to be applied to packets and/or frames and/or flows selected as a result of classification. SFC Operation, Administration and Maintenance can monitor the continuity of the SFC, i.e., that all elements of the SFC are reachable to each other in the downstream direction. But SFC OAM must support verification that the order of traversing these SFs corresponds to the state defined by the SFC control plane or ochestrator, the metric referred in this document as the path consistency of the SFC. This document defines a new SFC OAM method to support SFC consistency, i.e. verification that all elements of the given SFC are being traversed in the expected order. 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 December 31, 2017. Ao, et al. Expires December 31, 2017 [Page 1] Internet-Draft SFC OAM for path consistency June 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 2. Conventions used in this document . . . . . . . . . . . . . . 3 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3 3. Consistency OAM: Theory of Operation . . . . . . . . . . . . 3 3.1. COAM packet . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. SF Sub-TLV . . . . . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 5.1. COAM Message Types . . . . . . . . . . . . . . . . . . . 5 5.2. SFF Information Record TLV Type . . . . . . . . . . . . . 6 5.3. SF Information Sub-TLV Type . . . . . . . . . . . . . . . 6 5.4. SF Types . . . . . . . . . . . . . . . . . . . . . . . . 6 5.5. SF Identifier Types . . . . . . . . . . . . . . . . . . . 7 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 6.1. Normative References . . . . . . . . . . . . . . . . . . 8 6.2. Informational References . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction Service Function Chain (SFC) is a chain with a series of ordered Service Functions(SFs). Service Function Path (SFP) is a path of a SFC. SFC is described in detail in the SFC architecture document [RFC7665]. The SFs in the SFC are ordered and only when traffic is processed by one SF then it should be processed by the next SF, otherwise errors may occur. Sometimes, a SF needs to use the metadata from its upstream SF process. That's why it's very important for the operator to make sure that the order of traversing the SFs is exactly as defined by the control plane or the Ao, et al. Expires December 31, 2017 [Page 2] Internet-Draft SFC OAM for path consistency June 2017 orchestrator. This document refers to the correspondence between the state of control plane and the SFP itself as the SFP consistency. This document defines the method to check the path consistency of the SFP. It is an extension of the Overlay Echo-Request/Echo-reply specified in the [I-D.ooamdt-rtgwg-demand-cc-cv]. 2. Conventions used in this document 2.1. Terminology SFC(Service Function Chain): An ordered set of some abstract SFs. SFF: Service Function Forwarder SF: Service Function OAM: Operation, Administration and Maintenance SFP: Service Function Path COAM(Consistency OAM): OAM that can be used to check path consistency. 2.2. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 3. Consistency OAM: Theory of Operation Consistency OAM uses two functions: COAM Request and COAM Reply. The SFF, that is ingress of the SFP, transmits COAM Request packet. Every intermediate SFF that receives the COAM Request MUST perform the following actions: collect information of traversed by the COAM Request packet SFs and send it to the ingress SFF as COAM Reply packet over IP network [I-D.wang-sfc-multi-layer-oam]; forward the COAM Request to next downstream SFF if the one exists. As result, the ingress SFF collects information about all traversed SFFs and SFs, information of the actual path the COAM packet has traveled, so that we can verify the path consistency of the SFC. The Ao, et al. Expires December 31, 2017 [Page 3] Internet-Draft SFC OAM for path consistency June 2017 mechanism for the SFP consistency verification is outside the scope of this document. 3.1. COAM packet Consistency OAM introduces two new types of messages to the OOAM Echo Request/Reply operation [I-D.ooamdt-rtgwg-demand-cc-cv] with the following values Section 5.1: o TBA1 - COAM Request o TBA2 - COAM Reply An SFF, upon receiving the Consistency OAM Request, MUST include the corresponding SFs information, Section 3.2, into the Value field of the COAM Reply packet. The COAM packet is displayed in Figure 1. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message Type | Reply mode | Return Code | Return S.code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sender's Handle | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Value ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: COAM Packet Header 3.2. SF Sub-TLV Every SFF receiving COAM Request packet MUST include the SF characteristic data into the COAM Reply packet. The per SF data included in COAM Reply packet as SF Information sub-TLV that is displayed in Figure 2. After the COAM traversed the SFP, all the information of the SFs on the SFP are collected in the TLVs with COAM Reply. Ao, et al. Expires December 31, 2017 [Page 4] Internet-Draft SFC OAM for path consistency June 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SF sub-TLV Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SF Type | Service Index| SF ID Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SF Identifier | ~ ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Service Function sub-TLV SF TLV Type: indicate that the TLV is a SF TLV which contains the information of one SF. SF Type: indicates the type of SF, e.g., Firewall, Deep Packet Inspection, WAN optimization controller, etc. Service Index: indicates the SF's position on the SFP. SF ID Type: 0x01: IPv4 0x02: IPv6 0x03: MAC address 0x04-0xFF: Reserved SF Identifier: An identifier of the SF. The length of the SF Identifier depends on the type of the SF ID Type. For example, if the SF Identifier is its IPv4 address, the SF Identifier should be 32 bits. 4. Security Considerations Will be added in the future updates. 5. IANA Considerations 5.1. COAM Message Types IANA is requested to assign values from its Message Types sub- registry in Overlay Echo Request/Echo Reply Message Types registry as follows: Ao, et al. Expires December 31, 2017 [Page 5] Internet-Draft SFC OAM for path consistency June 2017 +-------+------------------------------+---------------+ | Value | Description | Reference | +-------+------------------------------+---------------+ | TBA1 | SFP Consistency Echo Request | This document | | TBA2 | SFP Consistency Echo Reply | This document | +-------+------------------------------+---------------+ Table 1: SFP Consistency Echo Request/Echo Reply Message Types 5.2. SFF Information Record TLV Type IANA is requested to assign new type value from SFC OAM TLV Type registry as follows: +-------+-----------------------------+---------------+ | Value | Description | Reference | +-------+-----------------------------+---------------+ | TBA3 | SFF Information Record Type | This document | +-------+-----------------------------+---------------+ Table 2: SFF-Information Record 5.3. SF Information Sub-TLV Type IANA is requested to assign new type value from SFC OAM TLV Type registry as follows: +-------+----------------+---------------+ | Value | Description | Reference | +-------+----------------+---------------+ | TBA4 | SF Information | This document | +-------+----------------+---------------+ Table 3: SF-Information Sub-TLV Type 5.4. SF Types IANA is requested create in the registry SF Types. All code points in the range 1 through 32759 in this registry shall be allocated according to the "IETF Review" procedure as specified in [RFC5226]. Code points in the range 32760 through 65279 in this registry shall be allocated according to the "First Come First Served" procedure as specified in [RFC5226]. Remaining code points are allocated according to the Table 4: Ao, et al. Expires December 31, 2017 [Page 6] Internet-Draft SFC OAM for path consistency June 2017 +---------------+--------------+-------------------------+ | Value | Description | Reference | +---------------+--------------+-------------------------+ | 0 | Reserved | This document | | 1- 32759 | Unassigned | IETF Review | | 32760 - 65279 | Unassigned | First Come First Served | | 65280 - 65519 | Experimental | This document | | 65520 - 65534 | Private Use | This document | | 65535 | Reserved | This document | +---------------+--------------+-------------------------+ Table 4: SF Type Registry This document defines the following new value in SF Type registry: +-------+-------------+---------------+ | Value | Description | Reference | +-------+-------------+---------------+ | TBA5 | Firewall | This document | +-------+-------------+---------------+ Table 5: SF Types 5.5. SF Identifier Types IANA is requested create in the registry SF Types the new sub- registry SF Identifier Types. All code points in the range 1 through 191 in this registry shall be allocated according to the "IETF Review" procedure as specified in [RFC5226] and assign values as follows: +------------+-------------+-------------------------+ | Value | Description | Reference | +------------+-------------+-------------------------+ | 0 | Reserved | This document | | TBA6 | IPv4 | This document | | TBA7 | IPv6 | This document | | TBA8 | MAC | This document | | TBA8+1-191 | Unassigned | IETF Review | | 192-251 | Unassigned | First Come First Served | | 252-254 | Unassigned | Private Use | | 255 | Reserved | This document | +------------+-------------+-------------------------+ Table 6: SF Identifier Type Ao, et al. Expires December 31, 2017 [Page 7] Internet-Draft SFC OAM for path consistency June 2017 6. References 6.1. Normative References [I-D.ooamdt-rtgwg-demand-cc-cv] Mirsky, G., Kumar, N., Kumar, D., Chen, M., Yizhou, L., and D. Dolson, "Echo Request and Echo Reply for Overlay Networks", draft-ooamdt-rtgwg-demand-cc-cv-03 (work in progress), March 2017. [I-D.wang-sfc-multi-layer-oam] Mirsky, G., Meng, W., Khasnabish, B., and C. Wang, "Multi- Layer OAM for Service Function Chains in Networks", draft- wang-sfc-multi-layer-oam-09 (work in progress), June 2017. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 5226, DOI 10.17487/RFC5226, May 2008, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 6.2. Informational References [RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function Chaining (SFC) Architecture", RFC 7665, DOI 10.17487/RFC7665, October 2015, . Authors' Addresses Ting Ao ZTE Corporation No.889, BiBo Road Shanghai 201203 China Phone: +86 21 68897642 Email: ao.ting@zte.com.cn Ao, et al. Expires December 31, 2017 [Page 8] Internet-Draft SFC OAM for path consistency June 2017 Greg Mirsky ZTE Corp. 1900 McCarthy Blvd. #205 Milpitas, CA 95035 USA Email: gregimirsky@gmail.com Zhonghua Chen China Telecom No.1835, South PuDong Road Shanghai 201203 China Phone: +86 18918588897 Email: 18918588897@189.cn Ao, et al. Expires December 31, 2017 [Page 9]