1 ## VPP Inband OAM (iOAM) {#ioam_plugin_doc}
3 In-band OAM (iOAM) is an implementation study to record operational
4 information in the packet while the packet traverses a path between
5 two points in the network.
7 Overview of iOAM can be found in [iOAM-Devnet] page.
8 The following IETF drafts detail the motivation and mechanism for
9 recording operational information:
10 - [iOAM-ietf-requirements] - Describes motivation and usecases for iOAM
11 - [iOAM-ietf-data] - Describes data records that can be collected using iOAM
12 - [iOAM-ietf-transport] - Lists out the transport protocols
13 and mechanism to carry iOAM data records
14 - [iOAM-ietf-proof-of-transit] - Describes the idea of Proof of Transit (POT)
15 and mechanisms to operationalize the idea
18 In-band OAM is expected to be deployed in a specific domain rather
19 than on the overall Internet. The part of the network which employs in-band OAM
20 is referred to as **"in-band OAM-domain"**.
22 In-band OAM data is added to a packet on entering the in-band OAM-domain
23 and is removed from the packet when exiting the domain.
24 Within the in-band OAM-domain, network nodes that the packet traverses
25 may update the in-band OAM data records.
27 - The node which adds in-band OAM data to the packet is called the
28 **"in-band OAM encapsulating node"**.
30 - The node which removes the in-band OAM data is referred to as the
31 **"in-band OAM decapsulating node"**.
33 - Nodes within the domain which are aware of in-band OAM data and read
34 and/or write or process the in-band OAM data are called
35 **"in-band OAM transit nodes"**.
37 ## Features supported in the current release
38 VPP can function as in-band OAM encapsulating, transit and decapsulating node.
39 In this version of VPP in-band OAM data is transported as options in an
40 IPv6 hop-by-hop extension header. Hence in-band OAM can be enabled
43 The following iOAM features are supported:
45 - **In-band OAM Tracing** : In-band OAM supports multiple data records to be
46 recorded in the packet as the packet traverses the network.
47 These data records offer insights into the operational behavior of the network.
48 The following information can be collected in the tracing
49 data from the nodes a packet traverses:
51 - Ingress interface ID
54 - Pre-configured application data
56 - **In-band OAM Proof of Transit (POT)**: Proof of transit iOAM data is
57 added to every packet for verifying that a packet traverses a specific
59 In-band OAM data is updated at every node that is enabled with iOAM
60 proof of transit and is used to verify whether a packet traversed
61 all the specified nodes. When the verifier receives each packet,
62 it can validate whether the packet traversed the specified nodes.
66 Configuring iOAM involves:
67 - Selecting the packets for which iOAM data must be inserted, updated or removed
68 - Selection of packets for iOAM data insertion on iOAM encapsulating node.
69 Selection of packets is done by 5-tuple based classification
70 - Selection of packets for updating iOAM data is implicitly done on the
71 presence of iOAM options in the packet
72 - Selection of packets for removing the iOAM data is done on 5-tuple
74 - The kind of data to be collected
77 - Additional details for processing iOAM data to be collected
78 - For trace data - trace type, number of nodes to be recorded in the trace,
79 time stamp precision, etc.
80 - For POT data - configuration of POT profile required to process the POT data
82 The CLI for configuring iOAM is explained here followed by detailed steps
83 and examples to deploy iOAM on VPP as an encapsulating, transit or
84 decapsulating iOAM node in the subsequent sub-sections.
86 VPP iOAM configuration for enabling trace and POT is as follows:
88 set ioam rewrite trace-type <0x1f|0x7|0x9|0x11|0x19>
89 trace-elts <number of trace elements> trace-tsp <0|1|2|3>
90 node-id <node ID in hex> app-data <application data in hex> [pot]
92 A description of each of the options of the CLI follows:
93 - trace-type : An entry in the "Node data List" array of the trace option
94 can have different formats, following the needs of the a deployment.
95 For example: Some deployments might only be interested
96 in recording the node identifiers, whereas others might be interested
97 in recording node identifier and timestamp.
98 The following types are currently supported:
99 - 0x1f : Node data to include hop limit (8 bits), node ID (24 bits),
100 ingress and egress interface IDs (16 bits each), timestamp (32 bits),
101 application data (32 bits)
102 - 0x7 : Node data to include hop limit (8 bits), node ID (24 bits),
103 ingress and egress interface IDs (16 bits each)
104 - 0x9 : Node data to include hop limit (8 bits), node ID (24 bits),
106 - 0x11: Node data to include hop limit (8 bits), node ID (24 bits),
107 application data (32 bits)
108 - 0x19: Node data to include hop limit (8 bits), node ID (24 bits),
109 timestamp (32 bits), application data (32 bits)
110 - trace-elts : Defines the length of the node data array in the trace option.
111 - trace-tsp : Defines the timestamp precision to use with the enumerated value
112 for precision as follows:
113 - 0 : 32bits timestamp in seconds
114 - 1 : 32bits timestamp in milliseconds
115 - 2 : 32bits timestamp in microseconds
116 - 3 : 32bits timestamp in nanoseconds
117 - node-id : Unique identifier for the node, included in the node ID
118 field of the node data in trace option.
119 - app-data : The value configured here is included as is in
120 application data field of node data in trace option.
121 - pot : Enables POT option to be included in the iOAM options.
123 ### Trace configuration
125 #### On in-band OAM encapsulating node
126 - **Configure classifier and apply ACL** to select packets for
128 - Example to enable iOAM data insertion for all the packets
129 towards IPv6 address db06::06:
131 vpp# classify table miss-next node ip6-lookup mask l3 ip6 dst
133 vpp# classify session acl-hit-next node ip6-add-hop-by-hop
134 table-index 0 match l3 ip6 dst db06::06
136 vpp# set int input acl intfc GigabitEthernet0/0/0 ip6-table 0
138 - **Enable tracing** : Specify node ID, maximum number of nodes for which
139 trace data should be recorded, type of data to be included for recording,
140 optionally application data to be included
141 - Example to enable tracing with a maximum of 4 nodes recorded
142 and the data to be recorded to include - hop limit, node id,
143 ingress and egress interface IDs, timestamp (millisecond precision),
144 application data (0x1234):
147 vpp# set ioam rewrite trace-type 0x1f trace-elts 4 trace-tsp 1
148 node-id 0x1 app-data 0x1234
152 #### On in-band OAM transit node
153 - The transit node requires trace type, timestamp precision, node ID and
154 optionally application data to be configured,
155 to update its node data in the trace option.
159 vpp# set ioam rewrite trace-type 0x1f trace-elts 4 trace-tsp 1
160 node-id 0x2 app-data 0x1234
162 #### On the In-band OAM decapsulating node
163 - The decapsulating node similar to encapsulating node requires
164 **classification** of the packets to remove iOAM data from.
165 - Example to decapsulate iOAM data for packets towards
166 db06::06, configure classifier and enable it as an ACL as follows:
169 vpp# classify table miss-next node ip6-lookup mask l3 ip6 dst
171 vpp# classify session acl-hit-next node ip6-lookup table-index 0
172 match l3 ip6 dst db06::06 opaque-index 100
174 vpp# set int input acl intfc GigabitEthernet0/0/0 ip6-table 0
177 - Decapsulating node requires trace type, timestamp precision,
178 node ID and optionally application data to be configured,
179 to update its node data in the trace option before it is decapsulated.
183 vpp# set ioam rewrite trace-type 0x1f trace-elts 4
184 trace-tsp 1 node-id 0x3 app-data 0x1234
187 ### Proof of Transit configuration
189 For details on proof-of-transit,
190 see the IETF draft [iOAM-ietf-proof-of-transit].
191 To enable Proof of Transit all the nodes that participate
192 and hence are verified for transit need a proof of transit profile.
193 A script to generate a proof of transit profile as per the mechanism
194 described in [iOAM-ietf-proof-of-transit] will be available at [iOAM-Devnet].
196 The Proof of transit mechanism implemented here is based on
197 Shamir's Secret Sharing algorithm.
198 The overall algorithm uses two polynomials
199 POLY-1 and POLY-2. The degree of polynomials depends on number of nodes
200 to be verified for transit.
201 POLY-1 is secret and constant. Each node gets a point on POLY-1
202 at setup-time and keeps it secret.
203 POLY-2 is public, random and per packet.
204 Each node is assigned a point on POLY-1 and POLY-2 with the same x index.
205 Each node derives its point on POLY-2 each time a packet arrives at it.
206 A node then contributes its points on POLY-1 and POLY-2 to construct
207 POLY-3 (POLY-3 = POLY-1 + POLY-2) using lagrange extrapolation and
208 forwards it towards the verifier by updating POT data in the packet.
209 The verifier constructs POLY-3 from the accumulated value from all the nodes
210 and its own points on POLY-1 and POLY-2 and verifies whether
211 POLY-3 = POLY-1 + POLY-2. Only the verifier knows POLY-1.
212 The solution leverages finite field arithmetic in a field of size "prime number"
213 for reasons explained in description of Shamir's secret sharing algorithm.
215 Here is an explanation of POT profile list and profile configuration CLI to
216 realize the above mechanism.
217 It is best to use the script provided at [iOAM-Devnet] to generate
219 - **Create POT profile** : set pot profile name <string> id [0-1]
220 [validator-key 0xu64] prime-number 0xu64 secret_share 0xu64
221 lpc 0xu64 polynomial2 0xu64 bits-in-random [0-64]
222 - name : Profile list name.
223 - id : Profile id, it can be 0 or 1.
224 A maximum of two profiles can be configured per profile list.
225 - validator-key : Secret key configured only on the
226 verifier/decapsulating node used to compare and verify proof of transit.
227 - prime-number : Prime number for finite field arithmetic as required by the
228 proof of transit mechanism.
229 - secret_share : Unique point for each node on the secret polynomial POLY-1.
230 - lpc : Lagrange Polynomial Constant(LPC) calculated per node based on
231 its point (x value used for evaluating the points on the polynomial)
232 on the polynomial used in lagrange extrapolation
233 for reconstructing polynomial (POLY-3).
234 - polynomial2 : Is the pre-evaluated value of the point on
235 2nd polynomial(POLY-2). This is unique for each node.
236 It is pre-evaluated for all the coefficients of POLY-2 except
237 for the constant part of the polynomial that changes per packet
238 and is received as part of the POT data in the packet.
239 - bits-in-random : To control the size of the random number to be
240 generated. This number has to match the other numbers generated and used
241 in the profile as per the algorithm.
243 - **Set a configured profile as active/in-use** :
244 set pot profile-active name <string> ID [0-1]
245 - name : Name of the profile list to be used for computing
247 - ID : Identifier of the profile within the list to be used.
249 #### On In-band OAM encapsulating node
250 - Configure the classifier and apply ACL to select packets for iOAM data insertion.
251 - Example to enable iOAM data insertion for all the packet towards
252 IPv6 address db06::06 -
255 vpp# classify table miss-next node ip6-lookup mask l3 ip6 dst
257 vpp# classify session acl-hit-next node
258 ip6-add-hop-by-hop table-index 0 match l3 ip6 dst db06::06
260 vpp# set int input acl intfc GigabitEthernet0/0/0 ip6-table 0
263 - Configure the proof of transit profile list with profiles.
264 Each profile list referred to by a name can contain 2 profiles,
265 only one is in use for updating proof of transit data at any time.
266 - Example profile list example with a profile generated from the
267 script to verify transit through 3 nodes is:
270 vpp# set pot profile name example id 0 prime-number 0x7fff0000fa884685
271 secret_share 0x6c22eff0f45ec56d lpc 0x7fff0000fa884682
272 polynomial2 0xffb543d4a9c bits-in-random 63
274 - Enable one of the profiles from the configured profile list as active
275 so that is will be used for calculating proof of transit
277 Example enable profile ID 0 from profile list example configured above:
280 vpp# set pot profile-active name example ID 0
283 - Enable POT option to be inserted
286 vpp# set ioam rewrite pot
289 #### On in-band OAM transit node
290 - Configure the proof of transit profile list with profiles for transit node.
294 vpp# set pot profile name example id 0 prime-number 0x7fff0000fa884685
295 secret_share 0x564cdbdec4eb625d lpc 0x1
296 polynomial2 0x23f3a227186a bits-in-random 63
298 #### On in-band OAM decapsulating node / verifier
299 - The decapsulating node, similar to the encapsulating node requires
300 classification of the packets to remove iOAM data from.
301 - Example to decapsulate iOAM data for packets towards db06::06
302 configure classifier and enable it as an ACL as follows:
305 vpp# classify table miss-next node ip6-lookup mask l3 ip6 dst
307 vpp# classify session acl-hit-next node ip6-lookup table-index 0
308 match l3 ip6 dst db06::06 opaque-index 100
310 vpp# set int input acl intfc GigabitEthernet0/0/0 ip6-table 0
312 - To update and verify the proof of transit, POT profile list should be configured.
313 - Example POT profile list configured as follows:
315 vpp# set pot profile name example id 0 validate-key 0x7fff0000fa88465d
316 prime-number 0x7fff0000fa884685 secret_share 0x7a08fbfc5b93116d lpc 0x3
317 polynomial2 0x3ff738597ce bits-in-random 63
321 Following CLIs are available to check iOAM operation:
322 - To check iOAM configuration that are effective use "show ioam summary"
326 vpp# show ioam summary
327 REWRITE FLOW CONFIGS - Not configured
328 HOP BY HOP OPTIONS - TRACE CONFIG -
329 Trace Type : 0x1f (31)
330 Trace timestamp precision : 1 (Milliseconds)
331 Num of trace nodes : 4
333 App Data : 0x1234 (4660)
334 POT OPTION - 1 (Enabled)
335 Try 'show ioam pot and show pot profile' for more information
337 - To find statistics about packets for which iOAM options were
338 added (encapsulating node) and removed (decapsulating node) execute
341 Example on encapsulating node:
346 1208804706 ip6-inacl input ACL hits
347 1208804706 ip6-add-hop-by-hop Pkts w/ added ip6 hop-by-hop options
349 Example on decapsulating node:
353 69508569 ip6-inacl input ACL hits
354 69508569 ip6-pop-hop-by-hop Pkts w/ removed ip6 hop-by-hop options
356 - To check the POT profiles use "show pot profile"
360 vpp# show pot profile
361 Profile list in use : example
362 POT Profile at index: 0
364 Validator : False (0)
365 Secret share : 0x564cdbdec4eb625d (6218586935324795485)
366 Prime number : 0x7fff0000fa884685 (9223090566081300101)
367 2nd polynomial(eval) : 0x23f3a227186a (39529304496234)
369 Bit mask : 0x7fffffffffffffff (9223372036854775807)
370 Profile index in use: 0
371 Pkts passed : 0x36 (54)
373 - To get statistics of POT for packets use "show ioam pot"
375 Example at encapsulating or transit node:
378 Pkts with ip6 hop-by-hop POT options - 54
379 Pkts with ip6 hop-by-hop POT options but no profile set - 0
380 Pkts with POT in Policy - 0
381 Pkts with POT out of Policy - 0
384 Example at decapsulating/verification node:
388 Pkts with ip6 hop-by-hop POT options - 54
389 Pkts with ip6 hop-by-hop POT options but no profile set - 0
390 Pkts with POT in Policy - 54
391 Pkts with POT out of Policy - 0
393 - Tracing - enable trace of IPv6 packets to view the data inserted and
396 Example when the nodes are receiving data over a DPDK interface:
397 Enable tracing using "trace add dpdk-input 20" and
398 execute "show trace" to view the iOAM data collected:
401 vpp# trace add dpdk-input 20
405 ------------------- Start of thread 0 vpp_main -------------------
409 00:00:19:294697: dpdk-input
410 GigabitEthernetb/0/0 rx queue 0
411 buffer 0x10e6b: current data 0, length 214, free-list 0, totlen-nifb 0, trace 0x0
412 PKT MBUF: port 0, nb_segs 1, pkt_len 214
413 buf_len 2176, data_len 214, ol_flags 0x0, data_off 128, phys_addr 0xe9a35a00
415 IP6: 00:50:56:9c:df:72 -> 00:50:56:9c:be:55
416 IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
417 tos 0x00, flow label 0x0, hop limit 63, payload length 160
418 00:00:19:294737: ethernet-input
419 IP6: 00:50:56:9c:df:72 -> 00:50:56:9c:be:55
420 00:00:19:294753: ip6-input
421 IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
422 tos 0x00, flow label 0x0, hop limit 63, payload length 160
423 00:00:19:294757: ip6-lookup
424 fib 0 adj-idx 15 : indirect via db05::2 flow hash: 0x00000000
425 IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
426 tos 0x00, flow label 0x0, hop limit 63, payload length 160
427 00:00:19:294802: ip6-hop-by-hop
428 IP6_HOP_BY_HOP: next index 5 len 96 traced 96 Trace Type 0x1f , 1 elts left
429 [0] ttl 0x0 node ID 0x0 ingress 0x0 egress 0x0 ts 0x0
431 [1] ttl 0x3e node ID 0x3 ingress 0x1 egress 0x2 ts 0xb68c2213
433 [2] ttl 0x3f node ID 0x2 ingress 0x1 egress 0x2 ts 0xb68c2204
435 [3] ttl 0x40 node ID 0x1 ingress 0x5 egress 0x6 ts 0xb68c2200
438 random = 0x577a916946071950, Cumulative = 0x10b46e78a35a392d, Index = 0x0
439 00:00:19:294810: ip6-rewrite
440 tx_sw_if_index 1 adj-idx 14 : GigabitEthernetb/0/0
441 IP6: 00:50:56:9c:be:55 -> 00:50:56:9c:df:72 flow hash: 0x00000000
442 IP6: 00:50:56:9c:be:55 -> 00:50:56:9c:df:72
443 IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
444 tos 0x00, flow label 0x0, hop limit 62, payload length 160
445 00:00:19:294814: GigabitEthernetb/0/0-output
447 IP6: 00:50:56:9c:be:55 -> 00:50:56:9c:df:72
448 IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
449 tos 0x00, flow label 0x0, hop limit 62, payload length 160
450 00:00:19:294820: GigabitEthernetb/0/0-tx
451 GigabitEthernetb/0/0 tx queue 0
452 buffer 0x10e6b: current data 0, length 214, free-list 0, totlen-nifb 0, trace 0x0
453 IP6: 00:50:56:9c:be:55 -> 00:50:56:9c:df:72
455 IP6_HOP_BY_HOP_OPTIONS: db05::2 -> db06::6
457 tos 0x00, flow label 0x0, hop limit 62, payload length 160
460 [iOAM-Devnet]: <https://github.com/ciscodevnet/iOAM>
461 [iOAM-ietf-requirements]:<https://tools.ietf.org/html/draft-brockners-inband-oam-requirements-01>
462 [iOAM-ietf-transport]:<https://tools.ietf.org/html/draft-brockners-inband-oam-transport-01>
463 [iOAM-ietf-data]:<https://tools.ietf.org/html/draft-brockners-inband-oam-data-01>
464 [iOAM-ietf-proof-of-transit]:<https://tools.ietf.org/html/draft-brockners-proof-of-transit-01>