[j-nsp] Juniper EX4550: 32k MAC Addresses but only 8k ARP Entries? What does that mean?

[v]

Hello,

I am trying to understand the datasheets for the EX switches. When I compare the EX4550 to the EX4600 like here:
http://www.juniper.net/us/en/products-services/switching/ex-series/compare/?product=P4550&pdpage=ex4550#a=P4550,P4600&p=

I find the following two lines:
"MAC Addresses 32k (EX4550) vs. 288k (EX4600)
ARP Entries 8k (EX4550) vs. 48k (EX4600)"

Can anyone explain the difference between those two metrics?

My Thoughts:
I guess "ARP Entries" is the number of MAC-to-IP mappings, which is relevant for using the Layer 3 capabilites of the switch.
And "MAC Addresses" is the number of MAC-to-Port mappings. So if i build a network with multiple switches connected one after another, I will only be able to build a network with up to 32k hosts. Is that correct?

Regards
v