Router as Computer
- Describe
Computers that specialize in sending packets over the data network. They are responsible for interconnecting networks by selecting the best path for a packet to travel and forwarding packets to their destination
- Routers are the network center
- WAN connection (Connection to ISP)
- LAN connection
- Data is sent in form of packets between 2 end devices
- Routers are used to direct packet to its destination
- Routers examine a packet’s destination IP address and determine the best path by enlisting the aid of a routing table
- Router components
- CPU
- Random access memory (RAM)
- Read-only memory (ROM)
- Non-volatile RAM (NVRAM)
- Flash memory
- Interfaces
- Major phases to the router boot-up process
- test router hardware
- Locate & load Cisco IOS software
- Locate & load startup configuration file or enter setup mode
- Verify the router boot-up process:
The show version command is used to view information about the router during the bootup process
- Routers and the Network Layer
Routers use destination IP address to forward packets
- The path a packet takes is determined after a router consults information in the routing table.
- After router determines the best path
- Packet is encapsulated into a frame
- Frame is then placed on network medium in form of Bits
- Routers Operate at Layers 1, 2 & 3
- Router receives a stream of encoded bits
- Bits are decoded and passed to layer 2
- Router de-encapsulates the frame
- Remaining packet passed up to layer 3
-Routing decision made at this layer by examining destination IP address
- Packet is then re-encapsulated & sent out outbound interface