User`s guide

Configuring IP Routing
Introduction to IP routing on the Pipeline
2-4 Preliminary January 30, 1998 Pipeline User’s Guide
Subnet mask notation
In the Pipeline, IP addresses are specified in decimal format (not hexadecimal).
For example:
198.5.248.40
If no netmask is specified, the Pipeline assumes a default netmask based on the
“class” of the address:
For example, a class C address such as 198.5.248.40 has 24 network bits, as
shown in Figure 2-2. That leaves 8 bits for the host portion of the address, so up
to 255 hosts can be supported on the class C network.
Figure 2-2. A class C address
To specify a netmask, the Pipeline does not use dotted decimal format, as in:
IP Address=198.5.248.40
Netmask=255.255.255.248
Instead, it includes a netmask modifier that specifies the total number of network
bits in the address. For example:
Table 2-1. IP address classes and default netmasks
Class Address range Network bits
Class A 0.0.0.0
→
127.255.255.255 8
Class B 128.0.0.0
→
191.255.255.255 16
Class C 192.0.0.0
→
223.255.255.255 24
Class D 224.0.0.0
→
239.255.255.255 N/A
Class E (reserved) 240.0.0.0
→
247.255.255.255 N/A