INTERNET-DRAFT J. Kumar Intended Status: Experimental S. Anubolu J. Lemon Broadcom Inc. H. Holbrook Arista Networks A. Ghanwani Dell EMC D. Cai H. OU AliBaba Inc. Y. Li Huawei Expires: April 21, 2019 October 18, 2018 Inband Flow Analyzer draft-kumar-ippm-ifa-00 Abstract Inband Flow Analyzer (IFA) records flow specific information from an end station and/or switches across a network. This document discusses the method to collect data on a per hop basis across a network and perform localized or end to end analytics operations on the data. This document also describes a transport-agnostic header definition that may be used for tunneled and non-tunneled flows alike. 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 Kumar, et al. [Page 1] INTERNET DRAFT IFA October 18, 2018 The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Copyright (c) 2018 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 . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.3 Applicability . . . . . . . . . . . . . . . . . . . . . . . 4 1.4 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 Encapsulation Requirements . . . . . . . . . . . . . . . . . 5 2.2 Operational Requirements . . . . . . . . . . . . . . . . . . 5 2.3 Cost and Performance Requirements . . . . . . . . . . . . . 6 3. IFA Operations . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1 IFA Zones . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2 IFA Function Nodes . . . . . . . . . . . . . . . . . . . . . 7 3.2.1 Initiating Function Node . . . . . . . . . . . . . . . . 8 3.2.2. Transit Function Node . . . . . . . . . . . . . . . . . 8 3.2.3. Terminating Function Node . . . . . . . . . . . . . . . 8 3.3 IFA Cloning, Truncation, and Drop . . . . . . . . . . . . . 8 3.4 IFA Header . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.4.1 IFA Option 1 Header . . . . . . . . . . . . . . . . . . 10 3.4.2 IFA Option 2 Header . . . . . . . . . . . . . . . . . . 11 3.5 IFA Metadata . . . . . . . . . . . . . . . . . . . . . . . . 11 3.5.1 Global Name Space (GNS) Identifier . . . . . . . . . . . 12 3.5.2 Local Name Space (LNS) Identifier . . . . . . . . . . . 12 3.5.3 Device ID . . . . . . . . . . . . . . . . . . . . . . . 13 3.6 IFA Network Overhead . . . . . . . . . . . . . . . . . . . . 13 3.7 IFA Analytics . . . . . . . . . . . . . . . . . . . . . . . 13 Kumar, et al. [Page 2] INTERNET DRAFT IFA October 18, 2018 3.8 IFA Packet Format . . . . . . . . . . . . . . . . . . . . . 13 3.8.1 TCP/UDP Packet . . . . . . . . . . . . . . . . . . . . . 14 3.8.2 VxLAN Packet . . . . . . . . . . . . . . . . . . . . . . 16 3.8.3 GRE Packet . . . . . . . . . . . . . . . . . . . . . . . 18 3.8.4 Geneve Packet . . . . . . . . . . . . . . . . . . . . . 20 3.9 IFA Load Balancing . . . . . . . . . . . . . . . . . . . . . 22 4. Interoperability Considerations . . . . . . . . . . . . . . . . 22 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 22 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23 6.1 Normative References . . . . . . . . . . . . . . . . . . . 23 6.2 Informative References . . . . . . . . . . . . . . . . . . . 23 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23 Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 A.1 Probe Marker . . . . . . . . . . . . . . . . . . . . . . . . 24 A.2 DSCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 A.3 IP Options . . . . . . . . . . . . . . . . . . . . . . . . . 25 A.4 IPv4 Identification or Reserved Flag . . . . . . . . . . . . 25 Kumar, et al. [Page 3] INTERNET DRAFT IFA October 18, 2018 1. Introduction This document describes an Inband Flow Analyzer (IFA) a mechanism to mark a packet to enable the collection of metadata regarding the analyzed flow. IFA defines an IFA header to mark the flow and direct the collection of analyzed metadata per marked packet per hop across a network. The ability to mark a packet using an IFA OAM header can be leveraged to create synthetic flows meant for network data collection. This document describes a mechanism that may be used to monitor live traffic and/or create synthetic flows. This document also describes IFA zones, IFA reports, and IFA metadata. IFA does not require changes to protocol headers in order to collect metadata or analyze flows. IFA puts minimal requirements on switching silicon. 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]. IFA: Inband Flow Analyzer MTU: Maximum Transmit Unit 1.2 Scope This document describes IFA deployment, the type of traffic that is supported, header definitions, analytics, and data path functions. IFA deployment involves defining an IFA zone and understanding the requirements in terms of traffic overhead and points of data collection. Given that IFA provides the ability to perform local analytics on the collected data, this document describes the scope of the analytics function as well. The scope of IFA is from an end station and/or ToR, through any/all nodes in the network, and terminating in a network switch and/or an end station. IFA can create a synthetic stream of traffic and use it to collect metadata along the path. This sampled stream is later discarded. IFA can also insert metadata on a per packet basis in live traffic. Inband insertion of metadata can be done within the payload or via tail stamping. This draft defines an identification mechanism using a dedicated protocol type in the IP header for identifying IFA. 1.3 Applicability IFA is capable of providing traffic analysis in an encapsulation- Kumar, et al. [Page 4] INTERNET DRAFT IFA October 18, 2018 agnostic manner. Simple TCP and UDP flows, as well as tunneled flows, can be monitored. IFA can be enabled on an end station, or it can be enabled just on network switches. Enabling IFA on an end station provides better scalability and visibility by monitoring intra end station or inter end station traffic. IFA performs best when there is hardware assistance for deriving the flow metadata in the data path. This document describes data path functions for IFA. 1.4 Motivation The main motivation for IFA is to collect analyzed metadata on a per packet per flow basis for a given application. The IFA header is defined in order to work for any IP packet, and with minimal impact on hardware performance. 2. Requirements IFA requirements are defined with operational efficiency, performance of the network, and cost of hardware in mind. 2.1 Encapsulation Requirements IFA packets MUST be clearly marked and identifiable so that a networking element in the flow path can insert metadata or perform other IFA operations. IFA packets need to be easily identified for performance reasons. IFA packet identification MUST be the same for all the encapsulation types. This means that expensive hardware modifications are not needed for supporting new protocol types. Since IFA packet processing is a data path function, the IFA header MUST avoid next header chaining. Simple parsing in the switch hardware is required to maintain the switch performance and cost. A single IFA encapsulation MUST support IPv4,IPv6 protocol types for tunneled and non-tunneled packets, preserving the fields used for load balancing hash computation. IFA SHOULD support a checksum for the entire IFA metadata stack instead of per metadata element. 2.2 Operational Requirements IFA MUST preserve the flow path across the network. IFA MUST incur minimal traffic overhead. Kumar, et al. [Page 5] INTERNET DRAFT IFA October 18, 2018 IFA MUST provide an option to clone and truncate a packet to avoid disrupting the PMTU discovery of a network. Cloning MUST be done at a sampled ratio to keep the network overhead minimum. IFA MUST provide the ability to insert metadata on cloned traffic. IFA MUST provide the ability to insert metadata on live traffic. IFA MUST provide the ability to specify checksum validation on the IFA header and metadata. IFA MUST provide the ability to define a zone using hop count. IFA MUST provide the ability for a networking element to perform metadata insertion in the payload or append it via tail stamping. IFA MUST be able to support an IFA zone name space, also referred to as a global name space. IFA MUST be able to support a per hop name space, also referred to as a local name space. 2.3 Cost and Performance Requirements The IFA header and metadata MUST be treated as foreign data present in the application data. IFA SHOULD be able to insert or strip the IFA data without modifying the layer 3 and layer 4 headers. This will help keep the cost of hardware down with no degradation in performance. IFA MUST support the ability to clone and/or truncate live traffic for IFA metadata insertion. This is needed for PMTU protocols to work well within the IFA zone. The IFA header MUST provide the ability to differentiate between a cloned packet and an original packet. This is needed for hardware to be able to identify and filter the cloned traffic at the edge of an IFA zone. IFA encapsulation MUST NOT impact the parse depth of hardware for packet processing. This will help avoid degradation in performance when IFA is enabled. IFA MUST NOT require pre-allocation for reserving the space in a packet. The overhead of managing reserved space in a packet can result in performance degradation. Kumar, et al. [Page 6] INTERNET DRAFT IFA October 18, 2018 3. IFA Operations IFA performs flow analysis, and possible actions on the flow data, inband. Once a flow is enabled for analysis, a node with the role of "Initiator" makes a copy of the flow or samples the live traffic flow, or tags a live traffic flow for analysis and data collection. Copying of a flow is done by sampling or cloning the flow. These new packets are representative packets of the original flow and possess the exact same characteristics as the original flow. This means that IFA packets traverse the same path in the network and same queues in the networking element as the original packet would. Figure 1 shows the IFA based Telemetry Framework. The terminating node is responsible for terminating the IFA flow by summarizing the metadata of the entire path and sending it to a Collector. +----------+ | | |Collector |--------------+ | | | +----------+ | | | | | | | | | +--------------+ +------------+ +----+-----------+ |Initiator Node| |Transit Node| |Terminating Node| | +------+ | | +------+ | | +------+ | | | IFA | |------->| | IFA | |------->| | IFA | | | +------+ |IFA flow| +------+ |IFA flow| +------+ | +--------------+ +------------+ +----------------+ Figure 1 IFA Zone Framework 3.1 IFA Zones An IFA zone is the domain of interest where IFA monitoring is enabled. An IFA zone MUST have designated IFA function nodes. An IFA zone can also be controlled by setting an appropriate TTL value in the L3 header. Initiating and Terminating function nodes are always at the edge of the IFA zone. Internal nodes in the IFA zone are always Transit function nodes. 3.2 IFA Function Nodes Kumar, et al. [Page 7] INTERNET DRAFT IFA October 18, 2018 There are three types of IFA functional nodes. 3.2.1 Initiating Function Node An end station, a switch, or any other middlebox can perform IFA initiating function. It is advantageous to keep this role closest to the application to maximize flow visibility. An IFA initiating function node performs the following functions: - Samples the flow traffic of interest based on a configuration. - Converts the traffic into an IFA flow by adding an IFA header to each sample. - Updates the packet with initiating function node metadata. - May mandate a specific template ID metadata by all networking elements. - May mandate tail stamping of metadata by all networking elements. 3.2.2. Transit Function Node An IFA transit node is responsible for inserting transit node metadata in an IFA packet. 3.2.3. Terminating Function Node An IFA terminating node is responsible for the following: - Inserts terminating node metadata in an IFA packet. - Performs a local analytics function on one or more segments of metadata, e.g., threshold breach for residence time, congestion notifications, and so on. - Filters an IFA flow in case of cloned traffic - Removes the IFA headers and forwards the packet in case of live traffic 3.3 IFA Cloning, Truncation, and Drop IFA allows cloning live traffic. Cloned traffic will have same network path characterization as the original traffic. Cloned traffic can be truncated to accommodate for PMTU of the IFA zone. Clone traffic MUST be dropped by the terminating node of IFA zone. 3.4 IFA Header A compact IFA header is described below. An experimental IP protocol number is used in the IP header to identify an IFA packet. The IP header protocol type field is copied into the IFA header NextHdr Kumar, et al. [Page 8] INTERNET DRAFT IFA October 18, 2018 field for hardware to correctly interpret the layer 4 header. 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 IPv4 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| IHL |Type of Service| Total Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identification |Flags| Fragment Offset | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Time to Live | Protocol = IFA| Header Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ or IPv6 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Traffic Class | Flow Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload Length |Next Hdr = IFA | Hop Limit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Source IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Destination IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IFA Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ver=2.0| GNS |NextHdr = IP_xx| Flags | Curr Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 IFA 2.0 Header Format Kumar, et al. [Page 9] INTERNET DRAFT IFA October 18, 2018 (1) Version (4 bits) - Specifies the version of IFA header. (2) GNS (4 bits) - Global Name Space. Specifies the IFA zone scoped name space for IFA metadata. (3) Protocol Type (8 bits) - IP Header protocol type. This is copied from the IP header. (4) Flags (8 bits) 0: Option1 - IFA Option 1. Indicates the presence of the Option 1 header. 1: TA - Turn Around. Indicates that the IFA packet needs to be turned around at the terminating node of the IFA zone. 2: I - Inband. Indicates this is live traffic. Strip and forward MUST be performed by the terminator node if this bit is set. 3: TS - Tail Stamp. Indicates the IFA zone is requiring tail stamping of metadata. 4: Reserved. MUST be initialized to 0 on transmission and ignored on receipt. 5: Reserved. MUST be initialized to 0 on transmission and ignored on receipt. 6: Reserved. MUST be initialized to 0 on transmission and ignored on receipt. 7: Option2 - IFA Option 2. Indicates the presence of the Option 2 checksum header. The checksum MUST be computed and updated for the IFA header and metadata. (5) Current Length (8 bits) - Specifies the current length of the metadata in multiples of 4 octets. 3.4.1 IFA Option 1 Header This header is optional. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Request Vector| Action Vector | Hop Limit | Max Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 IFA Option 1 Header Format Request Vector (8 bits) - This vector specifies the presence of fields as specified by GNS. Fields are always quad octet aligned. This field can be made extensible by defining a new GNS for an IFA zone. Action Vector (8 bits) - This vector specifies node-local or end-to- Kumar, et al. [Page 10] INTERNET DRAFT IFA October 18, 2018 end action on the IFA packets. Hop Limit (8 bits) - Specifies the maximum allowed hops in an IFA zone. This field is initialized by the initiator node. The hop limit MUST be decremented at each hop. If the hop limit becomes 0, transit nodes MUST stop inserting metadata. A value of 0xFF means that the Hop limit check MUST be ignored. Max Length (8 bits) - Specifies the maximum allowed length of metadata stack in multiples of 4 octets. This field is initialized by the initiator node. Each node in the path MUST compare the current length with the max length, and if the current length equals or exceeds the max length, the transit nodes MUST stop inserting metadata. 3.4.2 IFA Option 2 Header This header is optional. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Checksum | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4 IFA Option 2 Header Format Checksum (16 bits) - The checksum covering the IFA header and metadata stack. Reserved (16 bits) - Reserved. MUST be initialized to 0 on transmission and ignored on receipt. 3.5 IFA Metadata This is the information inserted by each hop after the IFA header. IFA metadata can be inserted at the following offsets: - Payload Stamping: Immediately after the layer 4 header - Tail Stamping: After the end of the packet Kumar, et al. [Page 11] INTERNET DRAFT IFA October 18, 2018 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LNS | Device ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | ~ LNS defined metadata (contd) ~ . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 IFA Metadata Format The IFA metadata header contains a set fields as defined by the name space identifier. Two types of name space identifiers are proposed. 3.5.1 Global Name Space (GNS) Identifier A GNS is specified in the IFA header by the initiator node. The scope of a GNS is an IFA zone. All networking elements in an IFA zone MUST insert metadata as per the GNS ID specified in the IFA header. This is defined as the "Uniform Mode" of deployment. A GNS value of 0xF indicates that metadata in an IFA zone is defined by the LNS of each hop. The advantage of using the uniform mode is having a simple and uniform metadata stack. This means less load on a collector for parsing. The disadvantage is that metadata fields are supported based on the least capable networking element in the IFA zone. 3.5.2 Local Name Space (LNS) Identifier An LNS is specified in the metadata header. A GNS value of 0xF in the IFA header indicates the presence of an LNS. A switch pipeline MUST parse the GNS field in the IFA header. The parsing result will dictate the name space ID that the hop needs to comply with. This is defined as the "Non-uniform Mode" of deployment. The advantage of using the non-uniform mode is having a flexible Kumar, et al. [Page 12] INTERNET DRAFT IFA October 18, 2018 metadata stack. This allows each hop to include the most relevant data for that hop. The disadvantage is more complex parsing by a collector. 3.5.3 Device ID A 28-bit unique identifier for the device inserting the metadata. If a GNS other than 0xF is present, then the device ID can be expanded to a 32 bit value. This is to support including an IPv4 loopback address as a Device ID. 3.6 IFA Network Overhead A common problem associated with inserting metadata on a per packet per flow basis is the amount of traffic overhead on the network. IFA 2.0 is defined to minimize the overhead on the network. IFA Base Header: 4 octets IFA Option 1 : 4 octets IFA Option 2 : 4 octets IFA metadata with LNS: 4 octets IFA metadata with GNS: 0 octets Minimum Overhead: IFA header : 4 octets IFA Metadata : 4 octets Total Overhead: 8 octets per packet 3.7 IFA Analytics There are two kinds of actions considered in this proposal. (1) Action Bit MAP in IFA Header - This is encoded in the IFA header. Each node in the path MAY use the action bitmap to insert or not insert the metadata based on exceeding a locally-specified threshold. Not inserting the metadata is indicated by setting the field value to -1 (all 1s). (2) Terminating Node Actions - A terminating node may decide to perform threshold or other actions on the set of metadata in the packet. This information is not encoded in the IFA header. 3.8 IFA Packet Format Kumar, et al. [Page 13] INTERNET DRAFT IFA October 18, 2018 The IFA header is treated as a layer 3 header extension. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IP Header | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IFA Header | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Layer 4 Header | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IFA Metadata Stack | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ~ | Layer 4 Header | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4 IFA Packet Format 3.8.1 TCP/UDP Packet Kumar, et al. [Page 14] INTERNET DRAFT IFA October 18, 2018 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 IPv4 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| IHL |Type of Service| Total Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identification |Flags| Fragment Offset | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Time to Live | Protocol = IFA| Header Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ or IPv6 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Traffic Class | Flow Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload Length |Next Hdr = IFA | Hop Limit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Source IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Destination IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IFA Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ver=2.0| GNS |NextHdr=TCP/UDP| Flags | Curr Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TCP Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | Kumar, et al. [Page 15] INTERNET DRAFT IFA October 18, 2018 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Acknowledgment Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Data | |U|A|P|R|S|F| | | Offset| Reserved |R|C|S|S|Y|I| Window | | | |G|K|H|T|N|N| | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Checksum | Urgent Pointer | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Options | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IFA Metadata Stack: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IFA Metadata Stack | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TCP Payload: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5 TCP/UDP IFA Packet Format 3.8.2 VxLAN Packet Kumar, et al. [Page 16] INTERNET DRAFT IFA October 18, 2018 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 IPv4 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| IHL |Type of Service| Total Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identification |Flags| Fragment Offset | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Time to Live | Protocol = IFA| Header Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ or IPv6 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Traffic Class | Flow Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload Length |Next Hdr = IFA | Hop Limit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Source IPv4 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Destination IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IFA Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ver=2.0| GNS | NextHdr = UDP | Flags | Curr Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Outer UDP Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Dest Port = VXLAN Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | UDP Length | UDP Checksum | Kumar, et al. [Page 17] INTERNET DRAFT IFA October 18, 2018 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IFA Metadata Stack: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IFA Metadata Stack | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ VXLAN Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |R|R|R|R|I|R|R|R| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | VXLAN Network Identifier (VNI) | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6 VxLAN IFA Packet Format 3.8.3 GRE Packet Kumar, et al. [Page 18] INTERNET DRAFT IFA October 18, 2018 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 IPv4 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| IHL |Type of Service| Total Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identification |Flags| Fragment Offset | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Time to Live | Protocol = IFA| Header Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ or IPv6 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Traffic Class | Flow Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload Length |Next Hdr = IFA | Hop Limit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Source IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Destination IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IFA Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ver=2.0| GNS | NextHdr = GRE | Flags | Curr Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ GRE Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |C| Reserved0 | Ver | Protocol Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Checksum (optional) | Reserved1 (Optional) | Kumar, et al. [Page 19] INTERNET DRAFT IFA October 18, 2018 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IFA Metadata Stack: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IFA Metadata Stack | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ GRE Payload: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7 GRE IFA Packet Format 3.8.4 Geneve Packet Kumar, et al. [Page 20] INTERNET DRAFT IFA October 18, 2018 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 IPv4 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| IHL |Type of Service| Total Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identification |Flags| Fragment Offset | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Time to Live | Protocol = IFA| Header Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination IPv4 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ or IPv6 Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Traffic Class | Flow Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload Length |Next Hdr = IFA | Hop Limit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Source IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Destination IPv6 Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IFA Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ver=2.0| GNS | NextHdr = UDP | Flags | Curr Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Outer UDP Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port = xxxx | Dest Port = Geneve Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | UDP Length | UDP Checksum | Kumar, et al. [Page 21] INTERNET DRAFT IFA October 18, 2018 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IFA Metadata Stack: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IFA Metadata Stack | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Geneve Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ver| Opt Len |O|C| Rsvd. | Protocol Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Virtual Network Identifier (VNI) | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Variable Length Options | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 8 Geneve IFA Packet Format 3.9 IFA Load Balancing IFA changes the IP protocol field value to IFA protocol number. IP protocol field value is included in the hash computation. This will impact load balancing of flows. Forwarding plane MUST support reading the IP protocol field value stored in IFA NextHDR field for hash computation. 4. Interoperability Considerations Version 2.0 of this protocol specification is not backward compatible with version 1.0. 5. Security Considerations A successful attack on an OAM protocol can prevent the detection of failures or anomalies, or create a false illusion of nonexistent ones. The metadata elements of IFA can be used by attackers to collect information about the network hops. Adding IFA headers or adding to IFA metadata can be used to consume resources within the path being monitored or by a collector. Adding IFA headers or adding to IFA metadata can be used to force Kumar, et al. [Page 22] INTERNET DRAFT IFA October 18, 2018 exceeding the MTU for the path being monitored resulting in fragmentation and/or packet drops. IFA is expected to be deployed within controlled network domains, containing attacks to that controlled domain. Limiting or preventing monitoring or attacks using IFA requires limiting or preventing unauthorized access to the domain in which IFA is to be used, and preventing leaking IFA metadata beyond the controlled domain. 6. References 6.1 Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 6.2 Informative References [RFC791] https://tools.ietf.org/html/rfc791 [RFC6864] https://tools.ietf.org/html/rfc6864 [RFC3514] https://tools.ietf.org/html/rfc3514 [IFA 1.0] https://tools.ietf.org/html/draft-kumar-ifa-00 Authors' Addresses Jai Kumar Broadcom Inc. Email: jai.kumar@broadcom.com Surendra Anubolu Broadcom Inc. Email: surendra.anubolu@broadcom.com John Lemon Broadcom Inc. Email: john.lemon@broadcom.com Hugh Holbrook Arista Networks Email: holbrook@arista.com Anoop Ghanwani Kumar, et al. [Page 23] INTERNET DRAFT IFA October 18, 2018 Dell EMC Email: anoop.ghanwani@dell.com Dezhong Cai AliBaba Inc. Email: d.cai@alibaba-inc.com Heidi OU AliBaba Inc. Email: heidi.ou@alibaba-inc.com Yizhou Li Huawei Technologies EMail: liyizhou@huawei.com Appendix A Appendix A is just for informational purposes. The following options were considered for the IFA protocol. A.1 Probe Marker One of the challenges of using probe signatures in an IFA header is a false positive. The IFA version 2.0 header takes care of large header sizes and identification based on probe markers. Probe markers can cause false positives if there is a match on the first 64 bits of the layer 4 payload. This approach is not a preferred approach, but is supported by this draft as a version 1.0 header. A.2 DSCP [RFC791] EXP/LU Pool 3 can be used for identifying IFA packets. CU bits can be used for identifying IFA packets. The problem with using TOS bits is that they are pervasively used in the network deployment and are responsible for affecting the forwarding decision. This approach is not supported or recommended by this draft. Kumar, et al. [Page 24] INTERNET DRAFT IFA October 18, 2018 A.3 IP Options [RFC791] The Options provide for control functions needed or useful in some situations but unnecessary for the most common communications. The options include provisions for timestamps, security, and special routing. There are various problems with this approach. (1) The IPv4 header size can become arbitrarily large with the presence of options. (2) A switch pipeline typically handles IP option packets as exception path processing and punts them to a host CPU. (3) IP options make the construction of firewalls cumbersome, and are typically disallowed or stripped at the perimeter of enterprise networks by firewalls. This approach is not supported or recommended by this draft. A.4 IPv4 Identification or Reserved Flag [RFC6864] [RFC3514] Another suggestion is to use the IPv4 identification field or reserved flag. This suggestion is also discarded and not supported for the following reasons: [RFC6864] prohibits usage of id field for any other purposes. [RFC3514] prohibits using flags bit 0 for security reasons. Kumar, et al. [Page 25]