4 ms·
I suspect it's because a lot of merchants are using terminals that are connecting over PSTN, or they don't hold a connection open between transactions so they h
by leejo 9y ago
I suspect it's because a lot of merchants are using terminals that are connecting over PSTN, or they don't hold a connection open between transactions so they have to do the connection dance for every transaction. Or they have connections that are just plain slow.
From my time writing backend banking integrations for a PSP, going on 5 years ago now, the time to authorise a card transaction (that's IP to BT gateway to X.25 network to acquiring bank to issuing bank and back again) would take anything between 0.2 and 1.0 seconds. So I don't believe it's actually down to any complexity in the authorisation steps if the transactions are done online.
- coleca 9y agoI see the same behavior in large chain stores such as Target, Lowes, and Walmart that would have dedicated private lines between the stores, their datacenter(s) and the banks. I've worked at a few large retailers and they typically had a hub and spoke model of network where all the stores would communicate over a private MPLS network to the datacenter where we had a "payment switch" (also called a payment gateway or router) dedicated individual redundant T3 lines to each card network (Amex, Discover, Mastercard/Visa, EBT, and gift card processors). This was at a chain with 200 stores. Larger chains would be even more robust I would imagine. I think the delays aren't network related, but more along the lines of the process that is happening. With mag stripe the approval flow was much simpler and happened in fractions of a second end to end. EMV is a different ballgame unfortunately.