I have my network up and passing traffic between the access, distribution, and core switches okay. We built the network based off of one of Cisco's High Availability network design documents. I was reading further in the document and it says that it is unnecessary to have all of the external routes, and it is a lot of external routes, on the access layer switches. The document claims that it doesn't serve a purpose.
Now my first question is why do they not serve a purpose? If the admin distance of the external EIGRP routes are higher wouldn't the traffic just be routed via the internal EIGRP routes down to the distribution switches since those are the next hop, or is my thinking not right?
My second question is how do you stop the access layer switches from receiving all of those unnecessary routes?
Mario is correct. If you want your access switches to have only one route, a default route, then the summary address is what you want but if you require more than i would look in to distribute lists.
Put the IP Summary address on the distribution switch, which will "advertise" a default route to the access switches. if you run a show ip route on the access switches you will only see a dynamic default route.
btw, you have 6509's as access switches???!!! I wish i had your budget! lol!