Netgear XCM8806 Chassis User Manual - Page 937

NETGEAR 8800 User Manual O (Continued) OSI reference model OSPF OSPFv3 OUI P packet PD PDU PIM-DM PIM-SM The 7-layer standard model for network architecture is the basis for defining network protocol standards and the way that data passes through the network. Each layer specifies particular network functions; the highest layer is closest to the user, and the lowest layer is closest to the media carrying the information. So, in a given message between users, there will be a flow of data through each layer at one end down through the layers in that computer and, at the other end, when the message arrives, another flow of data up through the layers in the receiving computer and ultimately to the end user or program. This model is used worldwide for teaching and implementing networking protocols. Open Shortest Path First. This is an IGP. OSPF, a routing protocol for TCP/IP networks, uses a link state routing algorithm that calculates routes for packets based on a number of factors, including least hops, speed of transmission lines, and congestion delays. You can also configure certain cost metrics for the algorithm. This protocol is more efficient and scalable than vector-distance routing protocols. OSPF features include least-cost routing, ECMP routing, and load balancing. Although OSPF requires CPU power and memory space, it results in smaller, less frequent router table updates throughout the network. This protocol is more efficient and scalable than vector-distance routing protocols. OSPFv3 is one of the routing protocols used with IPV6 and is similar to OSPF. The Organizational Unique Identifier is the first 24 bits of a MAC address for a network device that indicate a specific vendor as assigned by IEEE. This is the unit of data sent across a network. Packet is a generic term used to describe units of data at all levels of the protocol stack, but it is most correctly used to describe application data units. The packet is a group of bits, including data and control signals, arranged in a specific format. It usually includes a header, with source and destination data, and user data. The specific structure of the packet depends on the protocol used. Powered device. In PoE, the PD is the powered device that plugs into the PoE switch. Protocol data unit. A PDU is a message of a given protocol comprising payload and protocol-specific control information, typically contained in a header. Protocol-Independent Multicast - Dense mode. PIM-DM is a multicast protocol that uses Reverse Path Forwarding but does not require any particular unicast protocol. It is used when recipients are in a concentrated area. Protocol-Independent Multicast - Sparse mode. PIM-SM is a multicast protocol that defines a rendezvous point common to both sender and receiver. Sender and receiver initiate communication at the rendezvous point, and the flow begins over an optimized path. It is used when recipients are in a sparse area. Appendix E. Glossary | 937