Routing Switching are two different entities: routing and switching. Though they are different, the two concepts are united by the CCIE or Cisco Certified Internetwork Expert making them CCIE routing switching.
The CCIE routing switching is among the many tracks of examinations offered by the most challenging Cisco certification exam. Other than CCIE routing switching are other tracks like CCIE security, CCIE service provider, CCIE voice, and CCIE storage networking. The CCIE routing switching is the most popular among these other tracks with at least 14,329 CCIE routing and switching certified individuals in the world since late 2007.
Switching and routing in CCIE, as mentioned, are two different entities but work almost similar to each other. The basic difference between them is that switching works with switches while routing works with routers. The router is capable of determining the target point for sending packet through the NetworkID within a specific Network layer header. However, the switch is capable of maintaining a database of MAC address and to which port they are connected to. Switching also works with packets moved from one device to another in one network. The routing, on the other hand, can move packets between devices connected to different networks.
Having knowledge about routing and switching is necessary in order to successfully get a CCIE routing and switching certification. This particular certification, however, is not just as simple as the difference between routing and switching. CCIE routing switching involves various concepts on networking. This may include routing and switching, IP Interior Getaway Routing Protocols, Border Getaway Protocol, Multicast Routing, Quality Service, Security, and IP and IOS features.
Anyway, passing CCIE routing switching will be as easy as the alphabet with enough readings, knowledge, and long-time practice/experience on the field.