The arp entry is timing out. When it can't find an entry in the table, it will broadcast for the owner of the address. When the mac address is found, it will add the arp entry to it's table and start responding to pings. You can check this by doing:
sh arp | inc
on the switch. If it comes back to the prompt without any results, then it's not in the table. You can then ping the device, and do the same command above, and it should be there.
There is nothing called a "sleep mode" on cisco devices.. If it sleeps, the admins would be DEAD !
One reason to this might be because of the ARP entries aging out ! if you do not have IP communication happening, the ARP table can drop out the entry, and when you try pinging again, after a while, it might take 2-3 seconds to build up the entry ! that is why you can see a coupple of drops before the connection gets established..
this is true only for PC ports, but not point to point interfaces ! Request timed can happen due to other reasons too.. Bad link (look at reliability), duplex/ speed mismatches on switches etc.. So you gotta analyze everything
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...