Understanding IP Addressing B-13The following diagram illustrates the IP address space taken up by the two remote IP subnets. You can see fromthe diagram why the term nested is appropriate for describing these subnets.BroadcastsAs mentioned earlier, binary IP host or subnet addresses composed entirely of ones or zeros are reserved forbroadcasting. A broadcast packet is a packet that is to be delivered to every host on the network if both thehost address and the subnet address are all ones or all zeros, or to every host on the subnetwork if the hostaddress is all ones or all zeros but the subnet address is a combination or zeros and ones. Instead of makingmany copies of the packet, individually addressed to different hosts, all the host machines know to payattention to broadcast packets, as well as to packets addressed to their specific individual host addresses.Depending on the age and type of IP equipment you use, broadcasts will be addressed using either all zeros orall ones, but not both. If your network requires zeros broadcasting, you must configure this through SNMP.Packet header typesAs previously mentioned, IP works with other protocols to allow communication over IP networks. When IP isused on an Ethernet network, IP works with the Ethernet or 802.3 framing standards, among other protocols.These two protocols specify two different ways to organize the very first signals in the sequence of electricalsignals that make up an IP packet travelling over Ethernet. By default, the Netopia 4741 uses Ethernet packetheaders for IP traffic. If your network requires 802.3 IP framing, you must configure this through SNMP.1254Address rangeavailable toa.b.c.0, lessthe two nestedsubnets249valid addresses usedby a.b.c.248190129valid addresses usedby a.b.c.128
