networking router source of packet loss and transmission delays

Why are router source of packet loss and transmission delays?

From serverfault $pageUsers[$entry.posts[0].author].name

• Consider you have 2 hosts sending data as fast as they can to a third host, they all have 100Mbps connections. Which means the 2 hosts tries to fit 200Mbs onto the 100Mbs of the third host.

  What's the switch/router to do when its internal buffers are full - it has no other option besides to drop/reject further incoming packets, or drop packets based on some prioritizing criteria.

  Regarding delays, the more packets queued up for sending out to a host, the longer delays you get. Packets need to be sent serially, if 2 hosts tries to communicate with the same third host, they can't be sent out in parallell, so one of the packets have to wait until the first one is done transmitting.

  There's some internal delay as well, as the packet have to be read, and perhaps a route need to be looked up to figure out which port to send the packet to, or apply packet filtering etc. Exactly what and how this is done is very dependant on the internals of the router/switch ofcourse.

  From $pageUsers[$post.author].name