rogueqd wrote:ergocentric wrote:I'd have to disagree with you there and say the most reliable topology is a ring, if one cable fails the signal comes around from the other side.
Maybe for one break, but with a star you lose 1 client per break, with a ring you could lose all the clients with just 2 breaks. C'mon guys, what are we communicating on? A web is easily the most resilient.
unlikely to ever attach card access systems to the internets, ever
a ring will report the break immediately (as will a star) but the ring will keep everything connected in the downtime, very useful for card access, no client likes it when they cannot update the access codes (the card access panel itself is battery backed up and independent)
think of it like this: your phone goes to your two neighbours instead of the central office direct, this actually saves the phone company wire and money, and if one wire gets cut by digging they will know immediately and know which wire and the phones will all work until the van comes out on Thursday, if two wires get cut they will know which phones are disconnected and know which wires are cut and know to send the emergency repair crew (would they send an emergency repair crew if it was only your phone?)
web/mesh: more wires, more nodes, more resilient, more money, more maintenance