I will be getting a 30Mb connection for a LEC vendor. I am wanting to bring this into a single device before it goes into my network. I have been looking at the 2851 and the 3845 routers and it appears that the best practice is the 3800 series. If all I am going to be doing is an Ethernet connection for ingress and egress with no natting or ACL's on this router would a 2851 work?
The egress will be BGP and the ingress will be EIGRP.
I believe it would.
Attached is router performance document. Note the 2851 is rated 220 Kpps (fast path), and for 64 byte packets, equates to about 112 Mbps. Note that if your 30 Mbps is duplex, this would use slightly better than half of the total pps, but unlikely all your packets will be 64 bytes (bps throughput usually improves as the packet size increases).
Even the 2821 might be sufficent, but that's leaves little excess capacity.