Packet Forwarding and Delivery

Routing Fundamentals

• Routing is the process of selecting paths on a network along which packets are sent from a source to a destination.
• Path determination enables a router to compare the destination address to the available routes in its routing table and to select the best path.
• A routing device (Router) is a network device that forwards packets to a destination subnet based on routes.

Routing Information

• A route contains the following information: destination, mask, outbound interface, and next hop.
• Destination identifies a destination subnet.
• Mask identifies a subnet together with a destination IP address.
• Outbound interface indicates the interface through which a data packet is sent out of the local router.
• Next hop indicates the next-hop address used by the router to forward the data packet to the destination subnet.

Packet Forwarding

• Packet forwarding is the process of passing or moving information between interfaces.
• Packet forwarding is based on the "directions" in the routing table.

Packet Delivery

• Direct delivery occurs when the IP node forwards a packet to its final destination in the network.
• Indirect delivery occurs when the IP node forwards a packet to an intermediate node because the final destination is not on a directly attached network.

Routing Table

• A routing table is a database that contains information about which router network interface or port to place information to send it to a particular network segment.
• Destination/mask indicates the destination network address and mask of a specific route.

Address Resolution Protocol (ARP)

• ARP is a TCP/IP protocol that obtains the physical address of a node from a specific IP number.
• ARP is used to dynamically bind a high-level IP address to a low-level physical hardware address.

Reverse Address Resolution Protocol (RARP)

• RARP is a TCP/IP protocol that allows a host with no local permanent data storage media to find its Internet address given its physical address.

Common Network Access Layer Protocols

• Ethernet is a family of LANs, covered by a group of IEEE 802.3 standards.
• Ethernet is a best-effort delivery system that uses a CSMA/CD access method.
• Point-to-Point Protocol (PPP) is used for data transfer across a serial line.
• Fiber Distributed Data Interface (FDDI) is a set of ANSI protocols for sending digital data over fiber optic cable.
• Asynchronous Transfer Mode (ATM) is a wide area protocol that features high data rates and equalsized packets/cells suitable for text, audio, and video data transfer.
• Frame Relay is a WAN protocol for LAN internetworking that provides a fast and efficient method of transmitting information.
• Proxy ARP is used when a network terminal needs to pass data from one segment to another without changing its current IP address information.

This quiz covers packet forwarding and delivery, including the process of forwarding data packets and the different types of delivery methods. Learn about the role of IP nodes and the underlying physical networks.