Quality of Service is a technique that is used to manage network resources and guarantee a bandwidth
relationship between individual applications or protocols. A communications network transports a
multitude of applications and data, including high-quality video and delay-sensitive data such as real-
time voice. Networks must provide secure, predictable, measurable, and sometimes guaranteed
services. Achieving the required QoS becomes the secret to a successful end-to-end business solution.
RADIUS
RADIUS is a client/server protocol and software that enables remote access servers to communicate
with a central server to authenticate dial-in users and authorize their access to the requested system or
service. RADIUS allows a company to maintain user profiles in a central database that all remote servers
can share. It provides better security, allowing a company to set up a policy that can be applied at a
single administered network point. With RADIUS, you can track usage for billing and for keeping
network statistics.
RF
Radio Frequency is a frequency in the electromagnetic spectrum associated with radio wave
propagation. When an RF current is supplied to an antenna, an electromagnetic field is created that can
propagate through space. These frequencies in the electromagnetic spectrum range from Ultra-low
frequency (ULF):0-3 Hz to Extremely high frequency (EHF): 30 GHz–300 GHz. The middle ranges are:
Low frequency (LF): 30 kHz–300 kHz; Medium frequency (MF): 300 kHz–3 MHz; High frequency (HF): 3
MHz–30 MHz; Very high frequency (VHF): 30 MHz–300 MHz; and Ultra-high frequency (UHF): 300
MHz–3 GHz.
RFC
The IETF Request for Comments describe the definitions and parameters for networking. The RFCs are
catalogued and maintained on the IETF RFC website:
RIP
This IGP vector-distance routing protocol is part of the
suite and maintains tables of all known
destinations and the number of hops required to reach each. Using Routing Information Protocol,
routers periodically exchange entire routing tables. RIP is suitable for use only as an IGP.
RMON
Remote monitoring is a standardized method to make switch and router information available to
remote monitoring applications. It is an
SNMP (Simple Network Management Protocol)
network
management protocol that allows network information to be gathered remotely. RMON collects
statistics and enables a management station to monitor network devices from a central location. It
provides multivendor interoperability between monitoring devices and management stations. RMON is
described in more detail in IETF RFC 1757 and RFC 2201.
root bridge
, the root bridge is the bridge with the best bridge identifier selected to
be the root bridge. The network has only one root bridge. The root bridge is the only bridge in the
network that does not have a root port.
RSA
RSA is one of the first practicable public-key cryptosystems. It is widely used for secure data
transmission. In such a cryptosystem, the encryption key is public and differs from the decryption key
which is kept secret. In RSA, this asymmetry is based on the practical difficulty of factoring the product
Glossary
ExtremeSwitching 200 Series: Administration Guide
363
