HP ProCurve Secure 7000dl Series Basic Management And Configuration Manual page 763

large systems, the operating system ensures that different programs and users
running at the same time do not interfere with each other. The operating
system is also responsible for security, ensuring that unauthorized users do
not access the system.
OSI Open Systems Interconnection. Developed in 1982, the OSI was a joint effort
between ITU-T and ISO to create industry standards for network connections.
The OSI model was developed to allow for multi-vendor interoperability and
describes seven layers of connectivity.
7 Application Layer
Presentation Layer
6
5 Session Layer
4 Transport Layer
Network Layer
3
2 Data Link Layer
Physical Layer
1
Figure 2-1. The OSI model
OSPF Open Shortest Path First. A link-state routing protocol typically used within
larger networks. OSPF is an interior gateway protocol (IGP), which means
that it is used within a single AS. OSPF routers advertise the cost of their
connections to networks and to other routers so that they can compile a
topology of the network as a whole. Each router then generates a route to
each network in the AS. Routers select best routes according to link cost,
which is typically based on inverse bandwidth. OSPF is preferred over RIP, an
older routing protocol. For more information on OSPF, see RFC 2328 (at http:/
/www.ietf.org/rfc/rfc2328.txt). See also AS, LSA, and RIP.
OUI Organization Unique Identifier. A designation purchased from the IEEE for a
network-connected device. The OUI is a 48-bit unique MAC address that
specifies a single, specific piece of hardware on your network.
Appendix B: Glossary
B-37