We are going to discuss here two types of latencies: UniTiAgUniversal Ticketing Agent is a model of open-loop public transit ticketing using card-not-present transactions for fare acquiring. More TANBA Transit Agency API that gives access to a Transit Agency Ticketing System to its targeted OTRB data replica at the Regional UniTiAg Host. More APIApplication Program Interface More latency and Contactless Card-Present Payments Transaction latency. After that, we discuss latency-specific pros and cons of UniTiAgUniversal Ticketing Agent is a model of open-loop public transit ticketing using card-not-present transactions for fare acquiring. More model.
For the beginning, let’s consider some latency components.
Latency Components
NFC Channel Latency (250 – 450 msec)
This latency comprises the time the contactless card reader needs to engage the contactless card into transaction, read the data that the card presents to the reader, provide the data that the cards requests from the card reader, and execute ODAOffline Data Authentication. A contactless EMV process for ensuring that the tapped contactless card is genuine. More.
Detailed analysis of cEMVContactless EMV More tap latency is provided in this PCNPayments Consulting Network article. You can laso measure this latency and get a gist of data flows between the card reader and the card by using our android application NFC EMV Explorer.
Wired Latency (20 msec per 1000 km)
This latency includes the time it takes for an HTTP request from the client to reach the APIApplication Program Interface More host and for the response to return to the client. Host processing latency is not included in this measurement and is discussed separately. Additionally, we assume a stable Internet connection between the client and host, such as wired or fiber optic infrastructure, while wireless components are addressed separately.
This latency is influenced by geographical distance, with signal propagation in fiber optics being ~5 msec per 1000 km. Real-world latency, considering DNS resolution and handshaking, is typically 15-20 msec per 1000 km or more, depending on the network infrastructure.
Wireless Latency ( 30 msec to eternity)
This latency is important for wireless validatorsValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More, installed on vehicles. If the validatorValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More needs to connect to the host to send a message and receive a response via a wireless network, there will be time elapsed between sending a message to the host and receiving a response. We asume here that the host is very fast and is close to the client.
The current state of the wireless data communication technology demonstrates that the wireless latency can be as low as 30 msec. This latency is demonstrated if a wireless network has nothing else to do at that moment. We will treat this value as a low limit.
Unfortunately, the upper limit can not be determined. It could be up to several seconds or even minutes. Nobody knows how the wireless system will behave if there are several thousand bus validatorsValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More hammering the network with two requests per second at the rush time. Nobody knows how the cellular system will behave if there are many phone calls, SMS, or emails at the same time in a specific region. Current open-loopOpen-loop card is a payment card that can be accepted in many places, such as Visa card, Mastercard card, etc. Open-loop ticketing system allows fare payments with open-loop cards. More pilot projects run relatively small number of open-loopOpen-loop card is a payment card that can be accepted in many places, such as Visa card, Mastercard card, etc. Open-loop ticketing system allows fare payments with open-loop cards. More transactions via wireless channels and there is no reliable empiric data. The situation is even worse: there cannot be reliable statistical data or estimates of that kind obtained because of many unpredictable influential factors impacting the wireless data system throughput.
Host Latency (20-70 msec)
The computer host will require some time to process the requests. We should reasonably allow at least 20 msec to process a request and prepare the response. We do not count here the time the host needs to “talk” to some other systems such as Visa or MasterCard.
Authorization Latency (150 msec – 5 sec)
This latency is applicable for payments transaction. It includes time the Point-of-Sales would need to obtain the card issuer authorization through a payment scheme network. As UniTiAgUniversal Ticketing Agent is a model of open-loop public transit ticketing using card-not-present transactions for fare acquiring. More does not process and does not require TAsA transit operator or an agency representing several transit operators. The TA acts as a merchant from the UniTiAg’s standpoint. More to process card-present payment transactions, this latency is not applicable to the UniTiAgUniversal Ticketing Agent is a model of open-loop public transit ticketing using card-not-present transactions for fare acquiring. More model.
Cumulative Latency of TANB API cal “Get OTRB”
Let’s consider the following scenario. The ValidatorValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More, engages the card in cEMVContactless EMV More transaction, retrieves the data further required to process the fare (not a payment transaction) in UniTiAgUniversal Ticketing Agent is a model of open-loop public transit ticketing using card-not-present transactions for fare acquiring. More SaaSSoftware as a Service More and makes a request for the OTRBOpen-to-Ride Balance is an e-wallet monetary value for ticketing purposes, associated with a contactless token, shared between Transit Agencies. It can be pre-authorized, prepaid, postpaid, or a combination of thereof. More data associated wit this card, via TANBA Transit Agency API that gives access to a Transit Agency Ticketing System to its targeted OTRB data replica at the Regional UniTiAg Host. More APIApplication Program Interface More call “Get OTRB”.
The minimum and maximum cumulative latency values, separately for Wired ValidatorsValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More and Wireless ValidatorsValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More are presented in this illustrative table.
Latency (msec) | NFCNear-Field Communications, a protocol used for data exchange between contactless cards and readers. More Channel | Wired component (0 – 5000 km) | Host | Wireless component | Total for Wired ValidatorValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More | Total for Wireless ValidatorValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More |
---|---|---|---|---|---|---|
Min | 250 | 0 | 20 | 30 | 270 | 300 |
Max | 450 | 100 | 70 | Not possible to say | 620 | Not possible to say |
As we can see from this table, the wired validatorValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More, when it is close enough to the Regional UniTiAgUniversal Ticketing Agent is a model of open-loop public transit ticketing using card-not-present transactions for fare acquiring. More host, and when it is connected to this host via fast Internet infrastructure, can achieve reasonably low “Get OTRB” latency. As to wireless validatorsValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More, they would require the OTRBOpen-to-Ride Balance is an e-wallet monetary value for ticketing purposes, associated with a contactless token, shared between Transit Agencies. It can be pre-authorized, prepaid, postpaid, or a combination of thereof. More data pre-downloaded into their local memory which can be achieved by the TANBA Transit Agency API that gives access to a Transit Agency Ticketing System to its targeted OTRB data replica at the Regional UniTiAg Host. More APIApplication Program Interface More call “Sync OTRBs”.
If the wired validatorValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More is too far from the Regional UniTiAgUniversal Ticketing Agent is a model of open-loop public transit ticketing using card-not-present transactions for fare acquiring. More Host, an efficient approach would be for TAA transit operator or an agency representing several transit operators. The TA acts as a merchant from the UniTiAg’s standpoint. More to have its own ABTAccount-Based Ticketing is a public transit ticketing system model using patron accounts as a source of data for determining fares and validating access to services. More system host and periodically sync OTRBOpen-to-Ride Balance is an e-wallet monetary value for ticketing purposes, associated with a contactless token, shared between Transit Agencies. It can be pre-authorized, prepaid, postpaid, or a combination of thereof. More data with the Regional UniTiAgUniversal Ticketing Agent is a model of open-loop public transit ticketing using card-not-present transactions for fare acquiring. More Host using TANBA Transit Agency API that gives access to a Transit Agency Ticketing System to its targeted OTRB data replica at the Regional UniTiAg Host. More APIApplication Program Interface More call “Sync OTRBs”. The validatorsValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More will request OTRBOpen-to-Ride Balance is an e-wallet monetary value for ticketing purposes, associated with a contactless token, shared between Transit Agencies. It can be pre-authorized, prepaid, postpaid, or a combination of thereof. More data from the TAA transit operator or an agency representing several transit operators. The TA acts as a merchant from the UniTiAg’s standpoint. More host using an ABTAccount-Based Ticketing is a public transit ticketing system model using patron accounts as a source of data for determining fares and validating access to services. More proprietary APIs.
Cumulative Latency Of Card-Present Contactless Payment Transaction
The following tables represent the estimates for the time required if the card issuer authorization approval message needs to be obtained
Wired Validator – Full Authorization
Latency (msec) | NFCNear-Field Communications, a protocol used for data exchange between contactless cards and readers. More Channel | TA Host | Issuer Approval | Total |
---|---|---|---|---|
min | 250 | 70 | 150 | 470 |
max | 450 | 1000 | 5000 | 6450 |
Additional Latency for Wireless Validator
min | 30 |
---|---|
max | none can be guaranteed |
Maximal Allowed Transit Tap Latency
The reasonable tap latency in transit environment must not exceed in average 350-500 msec at subway turnstile and 500 – 1000 msec at bus validatorValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More.
This explains why the validatorValidator is a device with contactless card reader, registering card taps and validating access to the transit services. It is not a point of sale in UniTiAg model. More cannot wait for the card issuer authorization before granting access to the transit service. Waiting for the issuer response would impact the transit systems’ throughput and patron experience.
UniTiAg’s ticketing model, based on the OTRBOpen-to-Ride Balance is an e-wallet monetary value for ticketing purposes, associated with a contactless token, shared between Transit Agencies. It can be pre-authorized, prepaid, postpaid, or a combination of thereof. More concept and TANBA Transit Agency API that gives access to a Transit Agency Ticketing System to its targeted OTRB data replica at the Regional UniTiAg Host. More APIApplication Program Interface More, offers a low-latency solution for transit authorities, ensuring a risk-free fare validation process.