For IOS equivalent, I would look at netflow features or NBAR. If your IOS router is doing NAT, the 'show ip nat translations' command can show who 'has been talking recently'.

We tested the 1U (1.75-inch) Cisco 2801 and 2U (3.5-inch) Cisco 2851, each of which is designed to support multiple T-1 (1.544M-bps) WAN connections. Both models are available now.