A router is another network infrastructure device that directs packet through the network based on on information from network layer of OSI modal. A router uses a combination of
hardware and software to "rout" data from it source to its destination. A router can be configured to rout data packet from different. Network protocols,like TCP/IP ,IPX/SPX and apple talk.
Router segment large networks into logical segment called sub nets. The division of the network is based on the layer 3 addressing system, like IP addresses. If the network layer 3 data packet dose not across the router and
create a traffic congestion problem in another network. If data is addressing to a computeroutside the sub net.Thus routing of network data helps conserve network bandwidth. Thefollowing picture show cisco 2800 series router.
WHAT IS FIREWALL
Fire wall are use to protect a network data and resource from outside access and threats. A Firewall is used as a barrier between a internal network of an organization and network .
Since the primary function of a firewall is protect a network data and resource from outside threats , they are usually placed at the end point of a network.
A firewall can be dedicated hardware device, or software running in a computer.
Firewall can be configured with "rules". Firewall rules can be used to allows network traffic from the network. these rules can be based on source TCP port numbers, protocols, Application etc.
The Following image shows a cisco ASA 5520 firewall device.
hardware and software to "rout" data from it source to its destination. A router can be configured to rout data packet from different. Network protocols,like TCP/IP ,IPX/SPX and apple talk. 
