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Unread 11-01-2012, 09:55
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Re: cRIO Imaging Tool trouble

Quote:
Originally Posted by linuxboy View Post
Just wondering, since I like to know the details of what is actually going on, is the ARP table time to live on switches higher than on computers? Does windows just clear the ARP table when a cable is unplugged? Or am I misinterpreting the switch remembering the cRIO as an ARP thing when it really isn't?
As you know, a network switch maintains an ARP and ages out connections gracefully for efficency's sake. Switches, routers, gateways, access points all have to be much more forgiving that a computer's NIC, because they must deal with more simultaneous connections, and momentary (or longer) communication glitches are much more common. Devices connect and disconnect all the time, and switches also keep track of which network hops are likely to lead to twice-removed machines.

An individual computer's NIC typically only talks directly to or through one other device, while a switch must maintain connections to dozens. The timeout on a switch or NIC depends on the manufacturer's attitude towards who they consider their market, so some timeout quickly, while others are more forgiving and take longer.
Part of the reason for the quick-to-drop attitude may be the evolving nature of mobile devices that must be on the lookout to change APs rapidly to maintain the strongest network connection. Switches don't roam as much as laptops do (except for those on our robots maybe).
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