User`s guide

TCP/IP
QMS CrownNet System Administrator's GuideC-6
words, it creates a hierarchical address, which identifies a subnet
within an internet and then a host within a subnet.
The main advantage of subnetting is that it accommodates large
growth since a given gateway does not need to know as much detail
about distant destinations as it does about local ones.
Subnet Masks
» Note: If the subnet mask remains set to the default
(000.000.000.000) in the Administration/Communications/Network/
TCP/IP/Subnet Mask menu, the CrownNet interface provides
automatic sensing of gateways. If you identify a subnet mask, this
automatic sensing is disabled.
If a subnet address is used to identify a host, a corresponding 32-bit
subnet mask must also be designated. Like internet and subnet
addresses, the subnet mask is written in binary form for the network.
Bits are set to 1 if the network treats the corresponding bit in the inter-
net address as part of the network address, and to 0 if it treats the bit
as part of the host identifier. For example, the binary subnet mask
11111111 11111111 11111111 00000000
specifies that the first three groups of eight digits in the internet
address identify the network and subnet and that the fourth group
identifies the host on that subnet. However, these numbers are more
commonly written in decimal form. For example, the binary subnet
mask above would be written in decimal form as
255.255.255.0
Internet Routing
Once the internet address, subnet addresses, and subnet masks are
in place, information can be sent, or routed, to any destination in the
internet. Both hosts and gateways participate in the routing process.
If information is sent between two devices on a single physical net-
work, or subnet, no gateways are involved. The sending device
encapsulates the datagram in a physical frame, binds the destination