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Following the authentication process a session
key is generated for each transmission.
All data transfers are also encrypted against eavesdropping.
4.7.8 Timing
and Routing
The TransLink ® system architecture i l structure with the TransLink ®
Central System (TCS) at the top. The T d to all platforms at the next tier
rough Headquarter Computer Systems (HCS). An HCS has connections to, and
anages many TransLink ® s a hierarchica
CS is connecte
th
m
Data Servers (TDS). The TDS manages one or more Card
Interface Devices (CID)
or Distribution Devices (AVM).
Each node at a tier in the system communicates to all subordinate nodes and has a
single connection to the next higher tier. This requires all transactions in the TransLin
Fare Payment System (FPS) to be transported through each processing tier before
arriving at the TCS. The processing requirements of each level
determine what
transactions
are filtered and formatted into database structures.
All messages
must be forwarded to a higher
level until they reach the TCS. For
example, a message generated at a device is submitted
to the TDS then forwarded to the
HCS. The HCS then has the responsibility for sending
its transactions to the TCS.
provides four different date definitions in operation cycle as follows:
TransLink ®
• Operating
Date
• Business
Date
• Reconciliation Date
• Settlement
Date
T he current operating date is a date tha t may be different from the current calendar
date. For example, the current cal endar date may already be 18 February
2004, at 1:00
am, but the current operating date is still 17 February 2004 because the operating
date
changes eve ry day at 3:00 am.
The transaction business date is generated by a device, and added to the transaction
at
the TDS level. It is the current operating date of the device or TDS acquiring the device
UD. Typically, business dates reflect the operational business date of a transit
operator—the
period of their normal daily business hours. For example, if a transit
oper ator operates from 6:00 am to 2:00
am, (their business day), the business date
changeover will occur at 2:00 am. This allows the system to generate operational reports
that reflect transaction/passenger loads tied to their operational schedules. The
business date usually is applied at the devices or the TDS because these nodes typically
operate offline. The business date is typically incremented during the
transit operator
end-of-day
process.
The reconciliation date is added to the transaction
at the transit operator level. It is the
current operating date on the transit
operator’s central system. This date is used to
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