BROCADE IP PRIMER

GlossaryDCB Data Center Bridging. The DCB effort undertaken by the IEEE 802.1 workgroup adds new extensions to bridging and Ethernet, so that it becomes capableof converging LAN and storage traffic on a single link. Often, you hear that newDCB features will make Ethernet "like Fibre Channel." That’s true, because thenew features being added to Ethernet are solving issues that FC faced in thepast and successfully resolved. IEEE is expected to complete its work on thecomponents of DCB by the end of 2010. The new enhancements are PFC, ETS,and DCBX.DCBX Data Center Bridge eXchange. The role of DCBX is to allow two adjacentnodes to exchange information about themselves and what they support. Ifboth nodes support PFC and ETS, then a lossless link can be established tosupport the requirements of FCoE.DDoS Distributed Denial of Service. This describes a type of attack, in whichan attacker uses many different network nodes to overload a victim.Default gateway This is a special entry in a device's routing table. If the deviceneeds to reach an IP address for which it does not know the next-hop (e.g., theIP address is not in its routing table), it will forward the packet to the defaultgateway (if it is defined). It is a “gateway of last resort.”DHCP Dynamic Host Configuration Protocol. This is a protocol that is used toassign IP addresses, subnet masks, default gateways, and other network configurationitems automatically to hosts within a broadcast domain.Distance vector This is a routing protocol that chooses its best route by determiningthe least number of routers (hops) to get to the destination.DNS Domain Name System. This is a protocol that is designed to match a hostname to an IP address, and vice versa.DR Designated Router. In a broadcast multi-access OSPF area, this is therouter that will keep the master copy of the area's OSPF database. All otherrouters in the area will sync to this master. This router is decided on by an election.The router in second place becomes the Backup Designated Router(BDR), which will take over should the DR become unavailable.DSR Direct Server Return. This is a method of load balancing in which therequest is received by the load balancer, handed off to the real server, andfinally, the real server replies directly to the client (not through the load balancer).This provides maximum bandwidth to the client.Dual-mode In IEEE 802.1q tagging, dual-mode permits a single port to beboth an untagged member of one VLAN, and a tagged member of manyVLANs.EdgeIron This is the inexpensive low-end Layer 2 switch in the Brocade Line.These make ideal edge switches. They come in a stackable body.eBGP External Border Gateway Protocol. This describes a BGP environmentthat communicates from one AS to another. The Internet uses eBGP to traverseit.Brocade IP Primer 409