Nokia Network Voyager for IPSO 4.0 Reference Guide 46911 Configuring Router ServicesThis chapter describes how to enable your system to forward broadcast traffic by enabling the IPBroadcast Helper, forward BOOTP/DHCP traffic by enabling BOOTP relay, how to enablerouter discovery, and how to configure for Network Time Protocol (NTP).A Nokia appliance, like any routing device, does not forward broadcast traffic outside itsbroadcast domain as per ethernet standards. To have your appliance forward broadcast traffic,you must enable the IP Broadcast Helper, as described in “IP Broadcast Helper” on page 471. Toforward BOOTP/DHCP traffic, you must enable Bootp/DHCP Relay, as described in “BOOTP/DHCP Relay” on page 469. Both of these services listen for broadcasts on the configuredinterface and change them into a unicast transmission to the configured destination host.BOOTP/DHCP RelayBOOTP/DHCP Relay extends Bootstrap Protocol (BOOTP) and Dynamic Host ConfigurationProtocol (DHCP) operation across multiple hops in a routed network. In standard BOOTP, allinterfaces on a LAN are loaded from a single configuration server on the LAN. BOOTP Relayallows configuration requests to be forwarded to and serviced from configuration servers locatedoutside the single LAN.BOOTP Relay has the following advantages over standard BOOTP: It makes it possible to bootstrap load from redundant servers by allowing multiple servers tobe configured for a single interface. If one of the redundant configuration servers is unableto perform its job, another takes its place. It provides load balancing by allowing different servers to be configured for differentinterfaces instead of requiring all interfaces to be loaded from a single configuration server. It allows more centralized management of the bootstrap loading of clients. This advantagebecomes more important as the network becomes larger.The IPSO implementation of BOOTP Relay is compliant with RFC 951, RFC 1542, and RFC2131. BOOTP Relay supports Ethernet and IEEE 802 LANs by using canonical MAC byteordering, that is, clients that specify Bootp htype=1: 802.3 and FDDI.When an interface configured for BOOTP Relay receives a boot request, it forwards the requestto all the servers in its server list. It does this after waiting a specified length of time to see if alocal server answers the boot request. If a primary IP is specified, it stamps the request with thataddress, otherwise it stamps the request with the lowest numeric IP address specified for theinterface.
