HP-UX LAN Administrator's Guide (Feburary 2007)
Table Of Contents
- About This Document
- 1 New for the HP-UX 11i v3 Release
- 2 Installing HP-UX LAN
- 3 Configuring HP-UX LAN Using SAM
- 4 Manually Installing and Configuring HP-UX LAN
- 5 Troubleshooting HP-UX LAN
- Troubleshooting Overview
- Troubleshooting Q & A
- LAN Interface Card Statistics
- 100Base-T Checklist
- Diagnostic Flowcharts
- Flowchart 1: Configuration Test
- Flowchart 2: Configuration Test continued
- Flowchart 3: Configuration Test continued
- Flowchart 4: Network Level Loopback Test
- Flowchart 5: Network Level Loopback Test continued
- Flowchart 6: Transport Level Loopback Test (using Internet Services)
- Flowchart 7: Link Level Loopback Test
- Flowchart 8: LAN Connections Test
- Flowchart 9: Gateway Remote Loopback Test
- Flowchart 10: Gateway Remote Loopback Test continued
- Flowchart 11: Subnet Test
- 6 LAN Resources
- 7 Network Addressing
- Overview of Network Addressing Schemes
- Networking Terminology
- Network Addresses and Node Names
- Internet Addresses
- Subnet Addresses
- Configuring Gateways on Fixed-Length Subnets
- Variable-Length Subnet Addressing
- Configuring Gateways on Variable-Length Subnets
- Configuring Gateways on Supernets
- IP Multicast Addresses
- Virtual IP (VIP) Addresses
- CIDR - Classless Inter-Domain Routing
- 8 LAN Device and Interface Terminology
DRAFT COPY Network Addressing
Subnet Addresses
Chapter 7 107
The subnet field (the portion of an IP address that identifies the subnet beyond the network
portion of the address) can be all 0’s or all 1’s, as described in RFC 1878.To disallow subnet
fields with all ones or all zeroes (conform to RFC 1122 behavior), set the ndd parameter
ip_check_subnet_addr to 1 in the nddconf file (/etc/rc.config.d/nddconf).
Selecting a Subnet Addressing Scheme
In addition to fixed-length subnet addressing, HP-UX11i v3 systems support variable-length
subnet addressing. The advantages of using variable-length subnet addressing over
fixed-length subnet addressing include the following:
• Allows the local administrator to easily increase/decrease the size of individual subnets
when variable-length subnet addressing is used in conjunction with a non-contiguous
numbering system (and/or ranges of numbers for each subnet that are non-contiguous).
The mirror-image counting feature, which will be discussed in the following section, also
allows for more possibilities in the numbers that can be assigned to individual subnets.
• Reduces the amount of rework that network planners will have to do on network design
after the initial plan has been completed.
Fixed-length subnets were easy to implement, but growth restrictions often meant that it
was necessary to invest more time whenever a change was made to a subnet after it had
been originally designed.
This new feature also makes it possible to have more than one subnet mask on a network.
As described previously, an internet address can be represented as four fields separated by a
period, each of which represents 8 bits of the overall address.
The subnet address is based on the host address portion of the internet address. The host
address portion subdivides into subnet number and host number fields to accommodate a
given number of subnetworks and a given number of nodes per subnetwork. The size of the
subnet number field is determined by the subnet mask, which is explained later in this
section. The subnet number field must contain a minimum of one bit.
In the example below, the IP address, 192.6.12.33, has a subnet number of 1.