Virtual Ip Addresses; Virtual Ip Address Definitions And Characteristics; Definitions; Characteristics - Novell BUSINESS CONTINUITY CLUSTERING 1.0 - ADMINISTRATION Manual

Virtual IP Addresses

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With the release of NetWare® 6.5, Novell® has enhanced the TCP/IP stack to support virtual IP
addresses. This new feature is another high-availability offering that enables administrators to easily
manage the name-to-IP address associations of business services. It complements the existing load
balancing and fault tolerance features of the TCP/IP stack and enhances the availability of servers
that reside on multiple subnets.
A virtual IP address is an IP address that is bound to a virtual Network Interface Card (NIC) and is
driven by a new virtual driver named vnic.lan. As the name suggests, this virtual NIC is a purely
virtual entity that has no physical hardware counterpart. A virtual NIC can be thought of as a
conventional TCP/IP Loopback Interface with added external visibility. Virtual IP addresses can
also be thought of as conventional Loopback addresses with the 127.0.0.0 IP network constraint
relaxed. A server with a virtual NIC and a virtual IP address acts as an interface to a virtual internal
IP network that contains the server as the one and only host.
Regardless of their virtual nature, virtual IP addresses and virtual NICs essentially behave like
physical IP addresses and physical NICs, and they are similarly configured using either the
INETCFG server-based utility or the NetWare Remote Manager (NRM) Web-based utility.
3.1 Virtual IP Address Definitions and

Characteristics

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3.1.1 Definitions

Virtual driver: The vnic.lan driver provided by Novell.
Virtual board (NIC): Any board configured to use the virtual driver.
Virtual IP address: Any IP address that is bound to a virtual board.
Virtual IP network : The IP network that the virtual IP address is a part of. In practical terms, this is
defined by the virtual IP address together with the IP network mask that it is configured with.
Host mask: The IP network mask consisting of all 1s - FF.FF.FF.FF (255.255.255.255).
Physical IP address : Any IP address that is not a virtual IP address. In practical terms, it is an IP
address that is configured over a physical hardware NIC.
Physical IP network: An IP network that a physical IP address is a part of. In practical terms, a
physical IP network identifies a logical IP network that is configured over a physical hardware
wire.
3.1.2 Characteristics
Virtual IP addresses are unique in that they are bound to a virtual "ether" medium instead of to a
"physical" network medium such as Ethernet or token ring. In other words, the virtual IP address
space is exclusive from the physical IP address space. As a result, virtual IP network numbers need
to be different from physical IP network numbers. However, this mutual exclusivity of the IP
address space for the physical and virtual networks doesn't preclude the possibility of configuring
multiple virtual IP networks in a single network domain.
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