Routing Flashcards
What layer do bridges operate at, and what is their purpose?
Bridges operate at the data link layer and forward frames between networks using MAC addresses. They can connect different network types like Ethernet, FDDI, ATM, or 802.11g.
What are the two types of bridges?
No-Frills Bridges: Forward packets to all networks except the source network.
Learning Bridges: Cache source and destination ports to optimize forwarding and reduce bandwidth waste.
What layer do routers operate at, and what addressing do they use?
Routers operate at the network layer and forward packets using IP addresses.
What is the difference between direct and indirect delivery in routing?
Direct Delivery: Destination is on the same network as the source, using MAC addresses.
Indirect Delivery: Source and destination are on different networks, requiring routing algorithms to determine the next hop.
What are the two types of routing methods?
Static Routing: Manually updated routing tables, suitable for small or static networks.
Dynamic Routing: Automatically updates tables based on network changes, ideal for scalable and dynamic environments.
What is the purpose of a default route in a routing table?
To handle packets for unknown destinations, typically forwarding them to an external network like the internet.
How does IP routing work?
Use the subnet mask to calculate the network address of the destination.
If the destination is directly connected, forward the packet as a frame.
If not, perform a table lookup for the next hop or use the default route.
If no route exists, send an ICMP error message to the source.
What is source routing, and why is it rarely used?
Source routing allows the packet’s header to specify the route using a list of router IP addresses. It is rarely used due to security and complexity concerns.
How has routing evolved historically?
Early routing tables were managed manually, but dynamic, auto-configurable routing emerged in the 1980s to accommodate the growth of networks and the internet.
What is the cost range for routers, and what factors influence it?
Router costs range from $10,000 to $200,000, depending on their capabilities, such as support for multiple protocols (e.g., RIP, OSPF, MPLS) and scalability.
