--- /dev/null
+Inband OAM (iOAM)
+=================
+
+In-band OAM (iOAM) is an implementation study to record operational
+information in the packet while the packet traverses a path between two
+points in the network.
+
+Overview of iOAM can be found in
+`iOAM-Devnet <https://github.com/ciscodevnet/iOAM>`__ page. The
+following IETF drafts detail the motivation and mechanism for recording
+operational information: -
+`iOAM-ietf-requirements <https://tools.ietf.org/html/draft-brockners-inband-oam-requirements-01>`__
+- Describes motivation and usecases for iOAM -
+`iOAM-ietf-data <https://tools.ietf.org/html/draft-brockners-inband-oam-data-01>`__
+- Describes data records that can be collected using iOAM -
+`iOAM-ietf-transport <https://tools.ietf.org/html/draft-brockners-inband-oam-transport-01>`__
+- Lists out the transport protocols and mechanism to carry iOAM data
+records -
+`iOAM-ietf-proof-of-transit <https://tools.ietf.org/html/draft-brockners-proof-of-transit-01>`__
+- Describes the idea of Proof of Transit (POT) and mechanisms to
+operationalize the idea
+
+Terminology
+-----------
+
+In-band OAM is expected to be deployed in a specific domain rather than
+on the overall Internet. The part of the network which employs in-band
+OAM is referred to as **“in-band OAM-domain”**.
+
+In-band OAM data is added to a packet on entering the in-band OAM-domain
+and is removed from the packet when exiting the domain. Within the
+in-band OAM-domain, network nodes that the packet traverses may update
+the in-band OAM data records.
+
+- The node which adds in-band OAM data to the packet is called the
+ **“in-band OAM encapsulating node”**.
+
+- The node which removes the in-band OAM data is referred to as the
+ **“in-band OAM decapsulating node”**.
+
+- Nodes within the domain which are aware of in-band OAM data and read
+ and/or write or process the in-band OAM data are called **“in-band
+ OAM transit nodes”**.
+
+Features supported in the current release
+-----------------------------------------
+
+VPP can function as in-band OAM encapsulating, transit and decapsulating
+node. In this version of VPP in-band OAM data is transported as options
+in an IPv6 hop-by-hop extension header. Hence in-band OAM can be enabled
+for IPv6 traffic.
+
+The following iOAM features are supported:
+
+- **In-band OAM Tracing** : In-band OAM supports multiple data records
+ to be recorded in the packet as the packet traverses the network.
+ These data records offer insights into the operational behavior of
+ the network. The following information can be collected in the
+ tracing data from the nodes a packet traverses:
+
+ - Node ID
+ - Ingress interface ID
+ - Egress interface ID
+ - Timestamp
+ - Pre-configured application data
+
+- **In-band OAM Proof of Transit (POT)**: Proof of transit iOAM data is
+ added to every packet for verifying that a packet traverses a
+ specific set of nodes. In-band OAM data is updated at every node that
+ is enabled with iOAM proof of transit and is used to verify whether a
+ packet traversed all the specified nodes. When the verifier receives
+ each packet, it can validate whether the packet traversed the
+ specified nodes.
+
+Configuration
+-------------
+
+Configuring iOAM involves: - Selecting the packets for which iOAM data
+must be inserted, updated or removed - Selection of packets for iOAM
+data insertion on iOAM encapsulating node. Selection of packets is done
+by 5-tuple based classification - Selection of packets for updating iOAM
+data is implicitly done on the presence of iOAM options in the packet -
+Selection of packets for removing the iOAM data is done on 5-tuple based
+classification - The kind of data to be collected - Tracing data - Proof
+of transit - Additional details for processing iOAM data to be collected
+- For trace data - trace type, number of nodes to be recorded in the
+trace, time stamp precision, etc. - For POT data - configuration of POT
+profile required to process the POT data
+
+The CLI for configuring iOAM is explained here followed by detailed
+steps and examples to deploy iOAM on VPP as an encapsulating, transit or
+decapsulating iOAM node in the subsequent sub-sections.
+
+VPP iOAM configuration for enabling trace and POT is as follows:
+
+::
+
+ set ioam rewrite trace-type <0x1f|0x7|0x9|0x11|0x19>
+ trace-elts <number of trace elements> trace-tsp <0|1|2|3>
+ node-id <node ID in hex> app-data <application data in hex> [pot]
+
+A description of each of the options of the CLI follows: - trace-type :
+An entry in the “Node data List” array of the trace option can have
+different formats, following the needs of the a deployment. For example:
+Some deployments might only be interested in recording the node
+identifiers, whereas others might be interested in recording node
+identifier and timestamp. The following types are currently supported: -
+0x1f : Node data to include hop limit (8 bits), node ID (24 bits),
+ingress and egress interface IDs (16 bits each), timestamp (32 bits),
+application data (32 bits) - 0x7 : Node data to include hop limit (8
+bits), node ID (24 bits), ingress and egress interface IDs (16 bits
+each) - 0x9 : Node data to include hop limit (8 bits), node ID (24
+bits), timestamp (32 bits) - 0x11: Node data to include hop limit (8
+bits), node ID (24 bits), application data (32 bits) - 0x19: Node data
+to include hop limit (8 bits), node ID (24 bits), timestamp (32 bits),
+application data (32 bits) - trace-elts : Defines the length of the node
+data array in the trace option. - trace-tsp : Defines the timestamp
+precision to use with the enumerated value for precision as follows: - 0
+: 32bits timestamp in seconds - 1 : 32bits timestamp in milliseconds - 2
+: 32bits timestamp in microseconds - 3 : 32bits timestamp in nanoseconds
+- node-id : Unique identifier for the node, included in the node ID
+field of the node data in trace option. - app-data : The value
+configured here is included as is in application data field of node data
+in trace option. - pot : Enables POT option to be included in the iOAM
+options.
+
+Trace configuration
+~~~~~~~~~~~~~~~~~~~
+
+On in-band OAM encapsulating node
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- **Configure classifier and apply ACL** to select packets for iOAM
+ data insertion
+
+ - Example to enable iOAM data insertion for all the packets towards
+ IPv6 address db06::06:
+
+ vpp# classify table miss-next node ip6-lookup mask l3 ip6 dst
+
+ vpp# classify session acl-hit-next node ip6-add-hop-by-hop
+ table-index 0 match l3 ip6 dst db06::06
+
+ vpp# set int input acl intfc GigabitEthernet0/0/0 ip6-table 0
+
+- **Enable tracing** : Specify node ID, maximum number of nodes for
+ which trace data should be recorded, type of data to be included for
+ recording, optionally application data to be included
+
+ - Example to enable tracing with a maximum of 4 nodes recorded and
+ the data to be recorded to include - hop limit, node id, ingress
+ and egress interface IDs, timestamp (millisecond precision),
+ application data (0x1234):
+
+ vpp# set ioam rewrite trace-type 0x1f trace-elts 4 trace-tsp 1
+ node-id 0x1 app-data 0x1234
+
+On in-band OAM transit node
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- The transit node requires trace type, timestamp precision, node ID
+ and optionally application data to be configured, to update its node
+ data in the trace option.
+
+Example:
+
+::
+
+ vpp# set ioam rewrite trace-type 0x1f trace-elts 4 trace-tsp 1
+ node-id 0x2 app-data 0x1234
+
+On the In-band OAM decapsulating node
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- The decapsulating node similar to encapsulating node requires
+ **classification** of the packets to remove iOAM data from.
+
+ - Example to decapsulate iOAM data for packets towards db06::06,
+ configure classifier and enable it as an ACL as follows:
+
+ vpp# classify table miss-next node ip6-lookup mask l3 ip6 dst
+
+ vpp# classify session acl-hit-next node ip6-lookup table-index 0
+ match l3 ip6 dst db06::06 opaque-index 100
+
+ vpp# set int input acl intfc GigabitEthernet0/0/0 ip6-table 0
+
+- Decapsulating node requires trace type, timestamp precision, node ID
+ and optionally application data to be configured, to update its node
+ data in the trace option before it is decapsulated.
+
+Example:
+
+::
+
+ vpp# set ioam rewrite trace-type 0x1f trace-elts 4
+ trace-tsp 1 node-id 0x3 app-data 0x1234
+
+Proof of Transit configuration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For details on proof-of-transit, see the IETF draft
+`iOAM-ietf-proof-of-transit <https://tools.ietf.org/html/draft-brockners-proof-of-transit-01>`__.
+To enable Proof of Transit all the nodes that participate and hence are
+verified for transit need a proof of transit profile. A script to
+generate a proof of transit profile as per the mechanism described in
+`iOAM-ietf-proof-of-transit <https://tools.ietf.org/html/draft-brockners-proof-of-transit-01>`__
+will be available at
+`iOAM-Devnet <https://github.com/ciscodevnet/iOAM>`__.
+
+The Proof of transit mechanism implemented here is based on Shamir’s
+Secret Sharing algorithm. The overall algorithm uses two polynomials
+POLY-1 and POLY-2. The degree of polynomials depends on number of nodes
+to be verified for transit. POLY-1 is secret and constant. Each node
+gets a point on POLY-1 at setup-time and keeps it secret. POLY-2 is
+public, random and per packet. Each node is assigned a point on POLY-1
+and POLY-2 with the same x index. Each node derives its point on POLY-2
+each time a packet arrives at it. A node then contributes its points on
+POLY-1 and POLY-2 to construct POLY-3 (POLY-3 = POLY-1 + POLY-2) using
+lagrange extrapolation and forwards it towards the verifier by updating
+POT data in the packet. The verifier constructs POLY-3 from the
+accumulated value from all the nodes and its own points on POLY-1 and
+POLY-2 and verifies whether POLY-3 = POLY-1 + POLY-2. Only the verifier
+knows POLY-1. The solution leverages finite field arithmetic in a field
+of size “prime number” for reasons explained in description of Shamir’s
+secret sharing algorithm.
+
+| Here is an explanation of POT profile list and profile configuration
+ CLI to realize the above mechanism. It is best to use the script
+ provided at `iOAM-Devnet <https://github.com/ciscodevnet/iOAM>`__ to
+ generate this configuration. - **Create POT profile** : set pot
+ profile name id [0-1]
+| [validator-key 0xu64] prime-number 0xu64 secret_share 0xu64
+| lpc 0xu64 polynomial2 0xu64 bits-in-random [0-64]
+| - name : Profile list name. - id : Profile id, it can be 0 or 1. A
+ maximum of two profiles can be configured per profile list. -
+ validator-key : Secret key configured only on the
+ verifier/decapsulating node used to compare and verify proof of
+ transit. - prime-number : Prime number for finite field arithmetic as
+ required by the proof of transit mechanism. - secret_share : Unique
+ point for each node on the secret polynomial POLY-1. - lpc : Lagrange
+ Polynomial Constant(LPC) calculated per node based on its point (x
+ value used for evaluating the points on the polynomial) on the
+ polynomial used in lagrange extrapolation for reconstructing
+ polynomial (POLY-3). - polynomial2 : Is the pre-evaluated value of the
+ point on 2nd polynomial(POLY-2). This is unique for each node. It is
+ pre-evaluated for all the coefficients of POLY-2 except for the
+ constant part of the polynomial that changes per packet and is
+ received as part of the POT data in the packet. - bits-in-random : To
+ control the size of the random number to be generated. This number has
+ to match the other numbers generated and used in the profile as per
+ the algorithm.
+
+- **Set a configured profile as active/in-use** :
+ set pot profile-active name ID [0-1]
+
+ - name : Name of the profile list to be used for computing POT data
+ per packet.
+ - ID : Identifier of the profile within the list to be used.
+
+.. _on-in-band-oam-encapsulating-node-1:
+
+On In-band OAM encapsulating node
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- Configure the classifier and apply ACL to select packets for iOAM
+ data insertion.
+
+ - Example to enable iOAM data insertion for all the packet towards
+ IPv6 address db06::06 -
+
+ vpp# classify table miss-next node ip6-lookup mask l3 ip6 dst
+
+ vpp# classify session acl-hit-next node ip6-add-hop-by-hop
+ table-index 0 match l3 ip6 dst db06::06
+
+ vpp# set int input acl intfc GigabitEthernet0/0/0 ip6-table 0
+
+- Configure the proof of transit profile list with profiles. Each
+ profile list referred to by a name can contain 2 profiles, only one
+ is in use for updating proof of transit data at any time.
+
+ - Example profile list example with a profile generated from the
+ script to verify transit through 3 nodes is:
+
+ vpp# set pot profile name example id 0 prime-number
+ 0x7fff0000fa884685 secret_share 0x6c22eff0f45ec56d lpc
+ 0x7fff0000fa884682 polynomial2 0xffb543d4a9c bits-in-random 63
+
+- Enable one of the profiles from the configured profile list as active
+ so that is will be used for calculating proof of transit
+
+Example enable profile ID 0 from profile list example configured above:
+
+::
+
+ vpp# set pot profile-active name example ID 0
+
+- Enable POT option to be inserted
+
+ vpp# set ioam rewrite pot
+
+.. _on-in-band-oam-transit-node-1:
+
+On in-band OAM transit node
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- Configure the proof of transit profile list with profiles for transit
+ node. Example:
+
+ vpp# set pot profile name example id 0 prime-number
+ 0x7fff0000fa884685 secret_share 0x564cdbdec4eb625d lpc 0x1
+ polynomial2 0x23f3a227186a bits-in-random 63
+
+On in-band OAM decapsulating node / verifier
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- The decapsulating node, similar to the encapsulating node requires
+ classification of the packets to remove iOAM data from.
+
+ - Example to decapsulate iOAM data for packets towards db06::06
+ configure classifier and enable it as an ACL as follows:
+
+ vpp# classify table miss-next node ip6-lookup mask l3 ip6 dst
+
+ vpp# classify session acl-hit-next node ip6-lookup table-index 0
+ match l3 ip6 dst db06::06 opaque-index 100
+
+ vpp# set int input acl intfc GigabitEthernet0/0/0 ip6-table 0
+
+- To update and verify the proof of transit, POT profile list should be
+ configured.
+
+ - Example POT profile list configured as follows:
+
+ vpp# set pot profile name example id 0 validate-key
+ 0x7fff0000fa88465d prime-number 0x7fff0000fa884685 secret_share
+ 0x7a08fbfc5b93116d lpc 0x3 polynomial2 0x3ff738597ce bits-in-random
+ 63
+
+Operational data
+----------------
+
+Following CLIs are available to check iOAM operation: - To check iOAM
+configuration that are effective use “show ioam summary”
+
+Example:
+
+::
+
+ vpp# show ioam summary
+ REWRITE FLOW CONFIGS - Not configured
+ HOP BY HOP OPTIONS - TRACE CONFIG -
+ Trace Type : 0x1f (31)
+ Trace timestamp precision : 1 (Milliseconds)
+ Num of trace nodes : 4
+ Node-id : 0x2 (2)
+ App Data : 0x1234 (4660)
+ POT OPTION - 1 (Enabled)
+ Try 'show ioam pot and show pot profile' for more information
+
+- To find statistics about packets for which iOAM options were added
+ (encapsulating node) and removed (decapsulating node) execute *show
+ errors*
+
+Example on encapsulating node:
+
+::
+
+ vpp# show error
+ Count Node Reason
+ 1208804706 ip6-inacl input ACL hits
+ 1208804706 ip6-add-hop-by-hop Pkts w/ added ip6 hop-by-hop options
+
+Example on decapsulating node:
+
+::
+
+ vpp# show error
+ Count Node Reason
+ 69508569 ip6-inacl input ACL hits
+ 69508569 ip6-pop-hop-by-hop Pkts w/ removed ip6 hop-by-hop options
+
+- To check the POT profiles use “show pot profile”
+
+Example:
+
+::
+
+ vpp# show pot profile
+ Profile list in use : example
+ POT Profile at index: 0
+ ID : 0
+ Validator : False (0)
+ Secret share : 0x564cdbdec4eb625d (6218586935324795485)
+ Prime number : 0x7fff0000fa884685 (9223090566081300101)
+ 2nd polynomial(eval) : 0x23f3a227186a (39529304496234)
+ LPC : 0x1 (1)
+ Bit mask : 0x7fffffffffffffff (9223372036854775807)
+ Profile index in use: 0
+ Pkts passed : 0x36 (54)
+
+- To get statistics of POT for packets use “show ioam pot”
+
+Example at encapsulating or transit node:
+
+::
+
+ vpp# show ioam pot
+ Pkts with ip6 hop-by-hop POT options - 54
+ Pkts with ip6 hop-by-hop POT options but no profile set - 0
+ Pkts with POT in Policy - 0
+ Pkts with POT out of Policy - 0
+
+Example at decapsulating/verification node:
+
+::
+
+ vpp# show ioam pot
+ Pkts with ip6 hop-by-hop POT options - 54
+ Pkts with ip6 hop-by-hop POT options but no profile set - 0
+ Pkts with POT in Policy - 54
+ Pkts with POT out of Policy - 0
+
+- Tracing - enable trace of IPv6 packets to view the data inserted and
+ collected.
+
+Example when the nodes are receiving data over a DPDK interface: Enable
+tracing using “trace add dpdk-input 20” and execute “show trace” to view
+the iOAM data collected:
+
+::
+
+ vpp# trace add dpdk-input 20
+
+ vpp# show trace
+
+ ------------------- Start of thread 0 vpp_main -------------------
+
+ Packet 1
+
+ 00:00:19:294697: dpdk-input
+ GigabitEthernetb/0/0 rx queue 0
+ buffer 0x10e6b: current data 0, length 214, free-list 0, totlen-nifb 0, trace 0x0
+ PKT MBUF: port 0, nb_segs 1, pkt_len 214
+ buf_len 2176, data_len 214, ol_flags 0x0, data_off 128, phys_addr 0xe9a35a00
+ packet_type 0x0
+ IP6: 00:50:56:9c:df:72 -> 00:50:56:9c:be:55
+ IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
+ tos 0x00, flow label 0x0, hop limit 63, payload length 160
+ 00:00:19:294737: ethernet-input
+ IP6: 00:50:56:9c:df:72 -> 00:50:56:9c:be:55
+ 00:00:19:294753: ip6-input
+ IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
+ tos 0x00, flow label 0x0, hop limit 63, payload length 160
+ 00:00:19:294757: ip6-lookup
+ fib 0 adj-idx 15 : indirect via db05::2 flow hash: 0x00000000
+ IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
+ tos 0x00, flow label 0x0, hop limit 63, payload length 160
+ 00:00:19:294802: ip6-hop-by-hop
+ IP6_HOP_BY_HOP: next index 5 len 96 traced 96 Trace Type 0x1f , 1 elts left
+ [0] ttl 0x0 node ID 0x0 ingress 0x0 egress 0x0 ts 0x0
+ app 0x0
+ [1] ttl 0x3e node ID 0x3 ingress 0x1 egress 0x2 ts 0xb68c2213
+ app 0x1234
+ [2] ttl 0x3f node ID 0x2 ingress 0x1 egress 0x2 ts 0xb68c2204
+ app 0x1234
+ [3] ttl 0x40 node ID 0x1 ingress 0x5 egress 0x6 ts 0xb68c2200
+ app 0x1234
+ POT opt present
+ random = 0x577a916946071950, Cumulative = 0x10b46e78a35a392d, Index = 0x0
+ 00:00:19:294810: ip6-rewrite
+ tx_sw_if_index 1 adj-idx 14 : GigabitEthernetb/0/0
+ IP6: 00:50:56:9c:be:55 -> 00:50:56:9c:df:72 flow hash: 0x00000000
+ IP6: 00:50:56:9c:be:55 -> 00:50:56:9c:df:72
+ IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
+ tos 0x00, flow label 0x0, hop limit 62, payload length 160
+ 00:00:19:294814: GigabitEthernetb/0/0-output
+ GigabitEthernetb/0/0
+ IP6: 00:50:56:9c:be:55 -> 00:50:56:9c:df:72
+ IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
+ tos 0x00, flow label 0x0, hop limit 62, payload length 160
+ 00:00:19:294820: GigabitEthernetb/0/0-tx
+ GigabitEthernetb/0/0 tx queue 0
+ buffer 0x10e6b: current data 0, length 214, free-list 0, totlen-nifb 0, trace 0x0
+ IP6: 00:50:56:9c:be:55 -> 00:50:56:9c:df:72
+
+ IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
+
+ tos 0x00, flow label 0x0, hop limit 62, payload length 160
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