Netgear XCM8806 Chassis User Manual - Page 927

NETGEAR 8800 User Manual D (Continued) DF DHCP DiffServ DNS domain DoS attack DR dropped packets E EBGP Don't fragment bit. This is the don't fragment bit carried in the flags field of the IP header that indicates that the packet should not be fragmented. The remote host will return ICMP notifications if the packet had to be split anyway, and these are used in MTU discovery. Dynamic Host Configuration Protocol. DHCP allows network administrators to centrally manage and automate the assignment of IP addresses on the corporate network. DHCP sends a new IP address when a computer is plugged into a different place in the network. The protocol supports static or dynamic IP addresses and can dynamically reconfigure networks in which there are more computers than there are available IP addresses. Differentiated Services. Defined in RFC 2474 and 2475, DiffServ is an architecture for implementing scalable service differentiation in the Internet. Each IP header has a DiffServ (DS) field, formerly known as the Type of Service (TOS) field. The value in this field defines the QoS priority the packet will have throughout the network by dictating the forwarding treatment given to the packet at each node. DiffServ is a flexible architecture that allows for either end-to-end QoS or intradomain QoS by implementing complex classification and mapping functions at the network boundary or access points. In the NETGEAR implementation, you can configure the desired QoS by replacing or mapping the values in the DS field to egress queues that are assigned varying priorities and bandwidths. Domain Name Server. This system is used to translate domain names to IP addresses. Although the Internet is based on IP addresses, names are easier to remember and work with. All these names must be translated back to the actual IP address and the DNS servers do so. In CFM, a maintenance domain is the network, or part of the network, that belongs to a single administration for which connectivity faults are managed. Denial of service attacks occur when a critical network or computing resource is overwhelmed so that legitimate requests for service cannot succeed. In its simplest form, a DoS attack is indistinguishable from normal heavy traffic. XCM8800 software has configurable parameters that allow you to defeat DoS attacks. Designated router. In OSPF, the DR generates an LSA for the multiaccess network and has other special responsibilities in the running of the protocol. The DR is elected by the OSPF protocol. These are packets that the switch received but does not transmit. Exterior Border Gateway Protocol. EBGP is a protocol in the IP suite designed to exchange network reachability information with BGP systems in other ASs. EBGP works between different ASs. Appendix E. Glossary | 927