3Com OfficeConnect 3CR856-95 User Manual

Also see for OfficeConnect 3CR856-95: Installation guide User guide

Contents

68Type TwoIn larger networks, where there are more devices, the IP addressof ‘192.168.100.8’ is, again, split into two parts but is structureddifferently: Part one (‘192.168’) identifies the network on which thedevice resides. Part two (‘.100.8’) identifies the device within the network.This type of IP Address operates on a subnet mask of‘255.255.0.0’.See Table 4 for an example about how a network (only four PCsrepresented) and a Cable/DSL Secure Gateway might beconfigured.How does a Device Obtain an IP Address andSubnet Mask?There are three different ways to obtain an IP address and thesubnet mask. These are: Dynamic Host Configuration Protocol (DHCP) Addressing Static Addressing Automatic Addressing (Auto-IP Addressing)DHCP AddressingThe Cable/DSL Secure Gateway contains a DHCP server, whichallows computers on your network to obtain an IP address andsubnet mask automatically. DHCP assigns a temporary IP addressand subnet mask which gets reallocated once you disconnectfrom the network.DHCP will work on any client Operating System such asWindows® 95, Windows 98 or Windows NT 4.0. Also, usingDHCP means that the same IP address and subnet mask willnever be duplicated for devices on the network. DHCP isparticularly useful for networks with large numbers of users onthem.Static AddressingYou must enter an IP Address and the subnet mask manually onevery device. Using a static IP and subnet mask means theaddress is permanently fixed.Auto-IP AddressingNetwork devices use automatic IP addressing if they areconfigured to acquire an address using DHCP but are unable toCable/DSLSecure Gateway192.168.100.72 255.255.255.0Table 4 IP Addressing and Subnet Masking in a Large NetworkDevice IP Address Subnet MaskPC 1 192.168.100.8 255.255.0.0PC 2 192.168.201.30 255.255.0.0PC 3 192.168.113.155 255.255.0.0PC 4 192.168.002.230 255.255.0.0Cable/DSL SecureGateway192.168.002.72 255.255.0.0Table 3 IP Addressing and Subnet Masking in a Small NetworkDevice IP Address Subnet Maskdua08569-5aaa01.book Page 68 Wednesday, March 13, 2002 10:39 AM