Itm 440 Paper on Bonjour

ITM 440-­‐540 Introduc0on to Data Networking and the Internet

03/03/12

1

Router Architectures • There are 3 steps a router must follow to process and forward a packet to the next hop. – Check an incoming packet for errors and other parameters – Look up the des0na0on address in a forwarding table to determine the proper output port for the packet – Send the packet out the port

03/03/12

2

Router like a Train Roundhouse

03/03/12

3

Router Architecture • Rou0ng can be implemented using soKware based forwarding

– e.g small dsl router, linux box, etc

• Hardware Based – These are larger routers with forwarding fabric architectures. • ISP routers , Internet backbone, etc

03/03/12

4

Basic Hardware Routers • Routers are very much like computers. – CPU’s • Several types used not necessarily as powerful as pc

– NVRAM (Flash Memory) • Stores router configura0ons

– DRAM • Shared working storage

– ROM • Bootstrap for router OS 03/03/12 5

03/03/12 6

Larger Internet Routers • Fundamental principle is that the func0ons of a router can be split into two dis0nct parts – Rou0ng and control • Handles protocols, management of router, etc

– Forwarding