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Versions: 00 01

opsawg                                                       P. Lapukhov
Internet-Draft                                                  Facebook
Intended status: Standards Track                                R. Chang
Expires: December 12, 2016                             Barefoot Networks
                                                           June 10, 2016


           Data-plane probe for in-band telemetry collection
                   draft-lapukhov-dataplane-probe-01

Abstract

   Detecting and isolating network faults in IP networks has
   traditionally been done using tools like ping and traceroute (see
   [RFC7276]) or more complex systems built on similar concepts of
   active probing and path tracing.  While using active synthetic probes
   is proven to be helpful in detecting data-plane faults, isolating
   fault location is a much harder problem, especially in diverse
   networks with multiple active forwarding planes (e.g.  IP and MPLS).
   Moreover, existing end-to-end tools do not generally support
   functionality beyond dealing with packet loss - for example, they are
   hardly useful for detecting and reporting transient (i.e. milli- or
   even micro-second) network congestion.

   Modern network forwarding hardware can allow for more sophisticated
   data-plane functionality that provides substantial improvement to the
   isolation and identification capabilities of network elements.  For
   example, it has become possible to encode a snapshot of a network
   element's state within the packet payload as it transits the device.
   One example of such state would be queue depth on the egress port
   taken by that specific packet.  When combined with a unique device
   identifier embedded in the same packet, this could allow for precise
   time and topological identification of the the congested location
   within the network.

   This document proposes a format for requesting and embedding
   telemetry information in active probes, i.e. packet designated for
   actively testing the network while not carrying application traffic.
   These active probes could be conveyed over multiple protocols (ICMP,
   UDP, TCP, etc.) and the document does not prescribe any particular
   transport.  In addition, this document provides recommendations on
   handling the active probes by devices that do not support the
   required data-plane functionality.








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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
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   This Internet-Draft will expire on December 12, 2016.

Copyright Notice

   Copyright (c) 2016 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Data plane probe  . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Probe transport . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Probe structure . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  Header Format . . . . . . . . . . . . . . . . . . . . . .   5
     2.4.  Telemetry Data Frame and Telemetry Data Records . . . . .   7
   3.  Telemetry Record Types  . . . . . . . . . . . . . . . . . . .   8
     3.1.  Device Identifier . . . . . . . . . . . . . . . . . . . .   9
     3.2.  Timestamp . . . . . . . . . . . . . . . . . . . . . . . .   9
     3.3.  Queueing Delay  . . . . . . . . . . . . . . . . . . . . .   9
     3.4.  Ingress/Egress Port IDs . . . . . . . . . . . . . . . . .  10
     3.5.  Opaque State Snapshot . . . . . . . . . . . . . . . . . .  10
   4.  Operating in loopback mode  . . . . . . . . . . . . . . . . .  11
   5.  Processing Probe Packet . . . . . . . . . . . . . . . . . . .  11



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     5.1.  Detecting a probe . . . . . . . . . . . . . . . . . . . .  12
   6.  Non-Capable Devices . . . . . . . . . . . . . . . . . . . . .  12
   7.  Handling data-plane probes in the MPLS domain . . . . . . . .  12
   8.  Multi-chip device considerations  . . . . . . . . . . . . . .  12
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  13
     10.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   Detecting and isolating faults in IP networks may involve multiple
   tools and approaches, but by far the two most popular utilities used
   by operators are ping and traceroute.  The ping utility provides the
   basic end-to-end connectivity check by sending a special ICMP packet.
   There are other variants of ping that work using TCP or UDP probes,
   but may require a special responder application (for UDP) on the
   other end of the probed connection.

   This type of active probing approach has its limitations.  First, it
   operates end-to-end and thus it is impossible to tell where in the
   path the fault has happened from simply observing the packet loss
   ratios.  Secondly, in multipath (ECMP) scenarios it can be difficult
   to fully and/or deterministically exercise all the possible paths
   connecting two end-points.

   The traceroute utility has multiple variants as well - UDP, ICMP and
   TCP based, for instance, and special variant for MPLS LSP testing.
   Practically all variants follow the same model of operations: varying
   TTL field setting in outgoing probes and analyzing the returned ICMP
   unreachable messages.  This does allow isolating the fault down to
   the IP hop that is losing packets, but has its own limitations.  As
   with the ping utility, it becomes complicated to explore all possible
   ECMP paths in the network.  This is especially problematic in large
   Clos fabric topologies that are very common in large data-center
   networks.  Next, many network devices limit the rate of outgoing ICMP
   messages as well as the rate of "exception" packets "punted" to the
   control plane processor.  This puts a functional limit on the packet
   rate that the traceroute can probe a given hop with, and hence
   impacts the resolution and time to isolate a fault.  Lastly, the
   treatment for these control packets is often different from the
   packets that take regular forwarding path: the latter are normally
   not redirected to the control plane processor and handled purely in
   the data-plane hardware.

   Modern network processing elements (both hardware and software based)
   are capable of packet handling beyond basic forwarding and simple



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   header modifications.  Of special interest is the ability to capture
   and embed instantaneous state from the network element and encode
   this state directly into the transit packet.  One example would be to
   record the transit device's name, ingress and egress port
   identifiers, queueing delays, timestamps and so on.  By collecting
   this state along each network device in the path, it becomes trivial
   to trace a probe's path through the network as well as record transit
   device characteristics.  Extending this model, one could build a tool
   that combines the useful properties of ping and traceroute using a
   single packet flight through the network, without the constraints of
   control plane (aka "slow path") processing.  To aid in the
   development of such tooling, this document defines a format for
   requesting and embedding telemetry information in the body of active
   probing packets.

2.  Data plane probe

   This section defines the structure of the active data-plane probe.

2.1.  Probe transport

   This document does not prescribe any specific encapsulation for the
   data-plane probe.  For example, the probe could be embedded inside a
   UDP packet, or within an IPv6 extension header.

2.2.  Probe structure

   The probe consists of a fixed-size "Header" and arbitrary number of
   variable-length "telemetry data frames" following the header.  Frames
   are variable length, and each frame, in turn, consists of multiple
   "telemetry record" fields defined below in this document.  The
   records are added per the request of the telemetry information
   specified in the header.


















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   +---------------------------------------------------------+
   |                       Header                            |
   +---------------------------------------------------------+
   |                Telemetry data frame N                   |
   +---------------------------------------------------------+
   |                Telemetry data frame N-1                 |
   +---------------------------------------------------------+
   .                                                         .
   .                                                         .
   .                                                         .
   +---------------------------------------------------------+
   |                Telemetry data frame 1                   |
   +---------------------------------------------------------+

                          Figure 1: Probe layout

   Notice that the first frame is at the end of the packet.  For
   efficient hardware implementation, new frames are pushed onto the
   stack at each hop.  This eliminates the need for the transit network
   elements to inspect the full packet and allows for arbitrarily long
   packets as the MTU allows.

2.3.  Header Format

   The probe payload starts with a fixed-size header.  The header
   identifies the packet as a data-plane probe packet, and encodes basic
   information shared by all telemetry records.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Probe Marker (1)                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Probe Marker (2)                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Version     | Message Type  |             Flags             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Telemetry Request Vector                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Hop Limit   |   Hop Count   |         Must Be Zero          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Maximum Length        |        Current Length         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Sender's Handle        |        Sequence Number        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                          Figure 2: Header Format




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   (1)   The "Probe Marker" fields are arbitrary 32-bit values generally
         used by the network elements to identify the packet as a probe
         packet.  These fields should be interpreted as unsigned integer
         values, stored in network byte order.  For example, a network
         element may be configured to recognize a UDP packet destined to
         port 31337 and having 0xDEAD 0xBEEF as the values in "Probe
         Marker" field as an active probe, and treat it respectively.

   (2)   "Version Number" is currently set to 1.

   (3)   The "Message Type" field value could be either "1" - "Probe" or
         "2" - "Probe Reply"

   (4)   The "Flags" field is 8 bits, and defines the following flags:

   (5)

         (1)  "Overflow" (O-bit) (least significant bit).  This bit is
              set by the network element if the number of records on the
              packet is at the maximum limit as specified by the packet:
              i.e. the packet is already "full" of telemetry
              information.

   (6)   "Telemetry Request Vector" is a 32-bit long field that requests
         well-known inband telemetry information from the network
         elements on the path.  A bit set in this vector translates to a
         request of a particular type of information.  The following
         types/bits are currently defined, starting with the least
         significant bit first:

         (1)  Bit 0: Device identifier.

         (2)  Bit 1: Timestamp.

         (3)  Bit 2: Queueing delay.

         (4)  Bit 3: Ingress/Egress port identifiers.

         (5)  Bit 31: Opaque state snapshot request.

   (7)   "Hop Limit" is defined only for "Message Type" of "1"
         ("Probe").  For "Probe Reply" the "Hop Limit" field must be set
         to zero.  This field is treated as an integer value
         representing the number of network elements.  See the Section 4
         section on the intended use of the field.

   (8)   The "Hop Count" field specifies the current number of hops of
         capable network elements the packet has transit through.  It



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         begins with zero and must be incremented by one for every
         network element that adds a telemetry record.  Combined with a
         push mechanism, this simplifies the work for the subsequent
         network element and the packet receiver.  The subsequent
         network element just needs to parse the template and then
         insert new record(s) immediately after the template.

   (9)   The "Max Length" field specifies the maximum length of the
         telemetry payload in bytes.  Given that the sender knows the
         minimum path MTU, the sender can set the maximum of payload
         bytes allowed before exceeding the MTU.  Thus, a simple
         comparison between "Current Length" and "Max Length" allows to
         decide whether or not data could be added.

   (10)  The "Current Length" field specifies the current length of data
         stored in the probe.  This field is incremented by eacn network
         element by the number of bytes it has added with the telemetry
         data frame.

   (11)  The "Sender's Handle" field is set by the sender to allow the
         receiver to identify a particular originator of probe packets.
         Along with "Sequence Number" it allows for tracking of packet
         order and loss within the network.

2.4.  Telemetry Data Frame and Telemetry Data Records

   Each telemetry data frame is constructed by concatenating multiple
   telemetry data record, per the request in "Telemetry Request Vector"
   fields of the dataplane probe header.  The frame starts with a 16-bit
   length field, which reflects the frame size in bytes, excluding the
   length of the field itself.  Following the "Frame Length" field is a
   "Telemetry Response Vector" field: this vector corresponds to the
   records the network element was capable of recording in the frame.
   The body of the frame is constructed by appending fixed-size records
   corresponding to every bit set in "Telemetry Response Vector".  All
   of the records, except the one requested by 31st bit ("Opaque State
   Snapshot") are fixed size, with their lengths defined in Section 3.
   The order of the records in the frame follows the order of the bits
   in the "Telemetry Request Vector" (also reflected in "Telemetry
   Response Vector").  Finally, if requested, a variable-length field is
   appended at the end of the frame, with the length field occupying the
   first 8 bits.  This "length" field reflects the length of the opaque
   data excluding the length field itself.

   If inserting a new telemetry record would cause "Current Length" to
   exceed "Max Length", no record is added and the overflow "O-bit" must
   be set to "1" in the probe header.




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    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Frame  Length         |         Must be Zero          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Telemetry Response Vector                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   .                      Fixed Size Field 0                       .
   .                        (if requested)                         .
   .                                                               .
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   .                      Fixed Size Field 1                       .
   .                        (if requested)                         .
   .                                                               .
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   .                                                               .
   .                                                               .
   ~                                                               ~
   .                                                               .
   .                                                               .
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   .                      Fixed Size Field 30                      .
   .                        (if requested)                         .
   .                                                               .
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Length    |                                               |
   +-+-+-+-+-+-+-+-+                                               +
   |                                                               |
   .                   Opaque State Snapshot                       .
   .                       (if requested)                          .
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 3: Telemetry Frame Format

3.  Telemetry Record Types

   This section defines some of the telemetry record types that could be
   supported by the network elements.






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3.1.  Device Identifier

   This record is used to identify the device reporting telemetry
   information.  This document does not prescribe any specific
   identifier format.  In general, it is expected to be configured by
   the operator.  The length of this record is 32-bit.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Device ID                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                        Figure 4: Device Identifier

3.2.  Timestamp

   This telemetry record encodes the time data associated with the
   packet.  Most existing hardware support timestamping for IEEE1588.
   To leverage existing hardware capabilities, packet receive time is
   stored similarly as 48-bits of seconds, 32-bits of nanoseconds, and
   residence time is in 48-bits of nanoseconds.  The length of this
   record is 128 bits.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Receive Seconds [47:16]                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Receive Seconds [15:0]     |  Receive Nanoseconds [31:16]  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Receive Nanoseconds [15:0]   |     Residence Time [47:32]    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Residence Time [31:0]                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                            Figure 5: Timestamp

3.3.  Queueing Delay

   This record encodes the amount of time that the frame has spent
   queued in the network element.  This is only recorded if packet has
   been queued, and defines the time spent in memory buffers.  This
   could be helpful to detect queueing-related delays in the network.
   If the queueing delay exceeds the maximum number of 2+ seconds
   allowed by the 31-bit number, the network element must set the
   overflow "O-bit".  In case of the cut-through switching operation
   this must be set to zero.  The length of this record is 32 bits.



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    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |O|                        Nanoseconds                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                         Figure 6: Queueing Delay

3.4.  Ingress/Egress Port IDs

   This record stores the ingress and egress physical ports used to
   receive and send packet respectively.  Here, "physical port" means a
   unit with actual MAC and PHY devices associated - not any logical
   subdivision based, for example, on protocol level tags (e.g.  VLAN).
   The port identifiers are opaque, and defined as 16-bit entries.  For
   example, those could be the corresponding SNMP ifIndex values.  The
   length of this record is 32 bits.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Ingress Port ID        |        Egress Port ID         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 7: Ingress/Egress Port IDs

3.5.  Opaque State Snapshot

   This record has variable size.  It allows the network element to
   store arbitrary state in the probe, without a pre-defined schema.
   The schema needs to made known to the analyzer by some out-of-band
   means.  The 16-bit "Schema Id" field in the record is supposed to let
   the analyzer know which particular schema to use, and it is expected
   to be configured on the network element by the operator.  This ID is
   expected to be configured on the device by the network operator.
















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    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                    |         Schema Id             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                                                               |
   |                          Opaque Data                          |
   ~                                                               ~
   .                                                               .
   .                                                               .
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                          Figure 8: Opaque State

4.  Operating in loopback mode

   In "loopback" mode the flow of probes is "turned back" at some
   network element.  The network element that "turns" packets around is
   identified using the "Hop Limit" field.  The network element that
   receives a "Probe" type packet having "Hop Limit" value equal to "Hop
   Count" is required to perform the following:

      Change the "Message Type" field to "Probe Reply", and keep the
      "Hop Limit" at zero.

      Swap the destination/source IP addresses in the transport header
      to send the packet back to the originator.

      Add a new telemetry data frame corresponding to the new forwarding
      information.

   This way, the original probe is routed back to originator.  Notice
   that the return path may be different from the path that the original
   probe has taken.  This path will be recorded by the network elements
   as the reply is transported back to the sender.  Using this technique
   one may progressively test a path until its breaking point.

   If a network element is incapable of redirecting packets back to the
   originator, another option would be exporting those packets to a
   network analyzer device, using some sort of encapsulation header.

5.  Processing Probe Packet








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5.1.  Detecting a probe

   As mentioned previously, a combination of techniques need to be used
   to differentiate the active probes.  This may include, but should not
   be limited to using just the known position of "Probe Id" fields.

6.  Non-Capable Devices

   Non-capable devices are those that cannot process a probe natively in
   the fast-path data plane.  Further, there could be two types of such
   devices: those that can still process it via the control-plane
   software, and those that can not.  The control-plane processing
   should be triggered by use of the "Router-Alert" option for IPv4 of
   IPv6 packets (see [RFC2113] or [RFC2711]) added by the originator of
   the probe.  A control-plane capable device is expected to interpret
   and fill-in as much telemetry-record data as it possibly could, given
   the limited abilities.

   Network elements that are not capable of processing the data-plane
   probes are expected to perform regular packet forwarding.  If a
   network element receives a packet with the router-alert option set,
   but has no special configuration to detect such probes, it should
   process it according to [RFC6398].  Absence of the router alert
   option leaves the non dataplane-capable devices with the only option
   of processing the probe using traditional forwarding.

7.  Handling data-plane probes in the MPLS domain

   In general, the payload of an MPLS packet is opaque to the network
   element.  However, in many cases the network element still performs a
   lookup beyond the MPLS label stack, e.g. to obtain information such
   as L4 ports for load balancing.  It may be possible to perform data-
   plane probe classification in the same manner, additionally using the
   "Probe Marker" to distinguish the probe packets.

   In accordance to [RFC6178] Label Edge Routers (LERs) are required not
   to impose an MPLS router-alert label for packets carrying the router-
   alert option.  It may be beneficial to enable such translation, so
   that an end-to-end validation could be performed if a control-plane
   capable MPLS network element is present on the probe's path.

8.  Multi-chip device considerations

   TBD







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9.  IANA Considerations

   None

10.  References

10.1.  Normative References

   [RFC2113]  Katz, D., "IP Router Alert Option", RFC 2113,
              DOI 10.17487/RFC2113, February 1997,
              <http://www.rfc-editor.org/info/rfc2113>.

   [RFC2711]  Partridge, C. and A. Jackson, "IPv6 Router Alert Option",
              RFC 2711, DOI 10.17487/RFC2711, October 1999,
              <http://www.rfc-editor.org/info/rfc2711>.

   [RFC6398]  Le Faucheur, F., Ed., "IP Router Alert Considerations and
              Usage", BCP 168, RFC 6398, DOI 10.17487/RFC6398, October
              2011, <http://www.rfc-editor.org/info/rfc6398>.

   [RFC6178]  Smith, D., Mullooly, J., Jaeger, W., and T. Scholl, "Label
              Edge Router Forwarding of IPv4 Option Packets", RFC 6178,
              DOI 10.17487/RFC6178, March 2011,
              <http://www.rfc-editor.org/info/rfc6178>.

10.2.  Informative References

   [RFC7276]  Mizrahi, T., Sprecher, N., Bellagamba, E., and Y.
              Weingarten, "An Overview of Operations, Administration,
              and Maintenance (OAM) Tools", RFC 7276,
              DOI 10.17487/RFC7276, June 2014,
              <http://www.rfc-editor.org/info/rfc7276>.

Authors' Addresses

   Petr Lapukhov
   Facebook
   1 Hacker Way
   Menlo Park, CA  94025
   US

   Email: petr@fb.com









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Internet-Draft       draft-lapukhov-dataplane-probe            June 2016


   Remy Chang
   Barefoot Networks
   2185 Park Boulevard
   Palo Alto, CA  94306
   US

   Email: remy@barefootnetworks.com












































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