BROCADE IP PRIMER

GlossaryNIC Network Interface Controller. This is a controller that provides physicalaccess to your network medium.NSSA Not So Stubby Area. In OSPF, this is an area that can receive externalroutes (routes from outside of its AS) and advertise them to the backbone, butit cannot receive external routes from the backbone.Octet This is a collection of eight binary bits. This is very similar to a byte. Theterm "octet" is usually used when referring to an IP address. For example,using the address 192.168.123.11, the number “192” is the first octet (firsteight bits of the address), “168” is the second octet, “123” is the third octet,and “11” is the fourth octet.OSPF Open Shortest Path First. This is a link state routing protocol. It is wellsuitedfor large networks. It makes its routing decisions based on the bandwidthcost of the path to the destination. Collections of routers are subdividedinto areas.OUI Organizationally Unique Identifier. This is the first 24-bits of a MACaddress. These addresses correspond to a publicly-registered manufacturer ofthe NIC.Packet This is the data unit of the Network Layer.Packet capturing This is the process of recording duplicated frames traversinga network to troubleshoot or analyze the traffic.PAT Port Address Translation. This is a subset of NAT. Where NAT translatesone IP address into another, PAT translates according to a Layer 4 session(including the source and destination port in its tracking). This provides formultiple IP addresses to translate to the same single IP address, if desired.Path vector This describes a routing protocol that makes its decisions basedon the shortest path through larger groups of routers (Autonomous Systems).PBR Policy-Based Routing. This protocol allows a network engineer to makeexceptions to the routing table affecting only a select situation. For example,an incoming packet may be routed to a different destination to the same destinationnetwork depending on what its source address may be.Peer In BGP, this is the router that you establish a BGP session with. Withinthis session, you exchange routes and advertisements.PFC Priority-based Flow Control. The idea of PFC is to divide Ethernet trafficinto different streams or priorities. That way, an Ethernet device can distinguishbetween the different types of traffic flowing across a link and exhibitdifferent behaviors for different protocols.Physical Layer This is the first layer of the OSI Reference Model. This layer iswhere the transition is made from logical to physical. It receives frames fromthe Data Link Layer, converts them to binary bits, and transmits them via electricity,laser pulses, or whatever medium the layer uses. Data at this layer isrepresented by binary bits.Brocade IP Primer 415