Gigabit router architecture

I need to get some info on the architecture of gigabit routers. Can you suggest anything?

FW: MPLS and IS-IS

Hi all, IS-IS is defined to work with CLNP not for IP originally. Until today a lot of SONET and telecommunication equipment vendors still use IS-IS to route CLNP packets through the SONET Data communication channel(DCC) to carry management information and there is a great pressure to change