Bandwidth vs Uplink Port Speed

On Cisco routers you can use rate-limit based on an ACL that would do just that. I am not sure about switches though, so not sure if this information helps you at all (Other than maybe if these are catalyst switches it give you a keyword to google or try from ios):-/

On a router it would be something like:

interface FastEthernet2/0
 ip address 192.168.9.1 255.255.255.0
 rate-limit output access-group 151 96000 1500 2000 conform-action transmit exceed-action drop
!

access-list 151 deny   ip 192.168.0.0 0.0.255.255 any
...etc
access-list 151 permit ip any any

So maybe a L3 switch would be similar?

Short version:

Dedicated Instances - You pay for the instances, but they get placed on whatever dedicated hardware Amazon decides.

Dedicated Host - You pay for the entire physical server and can, in effect, run instances on it as you please.

Long version:

In both cases, its hardware that only your instances will use. However with dedicated hosts you have even more control than you would with dedicated instances. For example: Requesting a m4.large dedicated instance could end with your instance on a server exactly the size of an m4.large, so it'd be an old machine from years ago. Next time you reboot that instance it could be rebalanced onto new hardware. Maybe you have two dedicated instances that hammer the heck out of the RAM (making something up), they could end up on two different pieces of hardware or the same hardware.

On the flip side with a dedicated hardware, you pay for the hardware much in the same way you could pay for a leased server at a colo. You know exactly what the hardware is, you can run instances on it in the way you choose. You can leave overhead, or not. If you decide that instance X runs on your dedicated hardware, it will always run on that dedicated hardware in the way you've specified.