The RSP is the main processing engine for the 7500 router. It is not really an addon for a switch that allows it to route, more is the processing engine that includes the control plane and data plane for the 7500.
The control plane is responsible for establishing the routing table, CEF forwarding tables, peerings with other routers etc.
The data plane is responsible for forwarding the data. See attached sheet for more details
What you may be thinking of as an add on card is an MSFC - Multilayer (thanks Stephen !) Switch Feature card which can be added to a supervisor module for a 6500. With an MSFC the 6500 can be a L3 switch, without it is a Layer 2 switch.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...