Filtering IBGP Routes or advertise defaults?

Hi All,

I'm working on setting up a BGP config on two MX80 routers. I have two Cisco 4500X switch in a VSS pair as the core.

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I'm planning on taking full tables to the MX's but what i'm concerned about is the 4500's. The only have 4 gig 's of ram so I don't believe they'll be able to handle the bgp routes. So two options come to mind for me in this scenario.

Option one is filter the IBGP routes to the core (perahps not accept routes smaller than a /20 or larger?). Think this may give me stronger and more controlled routing options. But i'll leave you to judge.

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Option two is have the core not participate in BGP and just have the boarder routers advertise a default route via OSPF with different metrics. Let the boarder routers speak BGP (IBGP and EBPG).

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Overall just looking for thoughts.

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Thanks!