R
radar
Radar is a set of
advanced, intelligent,
Wireless-Intrusion-Detection-Service-Wireless-Intrusion-Prevention-Service (WIDS-WIPS)
features that are integrated into the Wireless Controller and its access points (APs). Radar
provides a basic solution for discovering unauthorized devices within the wireless coverage
area. Radar performs basic RF network analysis to identify unmanaged APs and personal ad-hoc
networks. The Radar feature set includes: intrusion detection, prevention and interference
detection.
RADIUS
Remote Authentication Dial In User Service. 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.
RARP
Reverse ARP. Using this protocol, a physical device requests to learn its IP address
from a gateway server's ARP table. When a new device is set up, its RARP client program
requests its IP address from the RARP server on the router. Assuming that an entry has been
set up in the router table, the RARP server will return the IP address to the machine which
can store it for future use.
rate limiting
In
QoS, rate limiting is the process of
restricting traffic to a peak rate (PR).
For more
information, see rate limiting and rate shaping in the ExtremeXOS 21.1 User Guide.
rate shaping
In
QoS, rate shaping is the process of reshaping
traffic throughput to give preference to higher priority traffic or to buffer traffic until
forwarding resources become available.
For more
information, see rate limiting and rate shaping in the ExtremeXOS 21.1 User Guide.
RF
Radio Frequency. 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
Request for Comment. The IETF RFCs describe the definitions and parameters for
networking. The RFCs are catalogued and maintained on the IETF RFC website:
www.ietf.org/rfc.html.
Ridgeline
Ridgeline is an Extreme Networks-proprietary graphical user interface (GUI) network
management system. The name was changed from EPICenter to Ridgeline in 2011.
RIP
Routing Information Protocol. This IGP vector-distance routing protocol is part of the
TCP/IP suite and maintains tables of all known destinations and the number of hops required to
reach each. Using RIP, routers periodically exchange entire routing tables. RIP is suitable
for use only as an IGP.
RIPng
RIP next generation.
RIPng is one of the routing protocols used with IPv6 and is similar to RIP.
RMON
Remote monitoring. RMON is a standardized method to make switch and router information
available to remote monitoring applications. It is an SNMP 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 several RFCs (among them IETF RFC 1757 and RFC 2201).
Network administrators use RMON to monitor, analyze, and troubleshoot the network. A
software agent can gather the information for presentation to the network administrator with
a graphical user interface (GUI). The administrator can find out how much bandwidth each
user is using and what web sites are being accessed; you can also set alarms to be informed
of potential network problems.
roaming
In 802.11, roaming
occurs when a wireless device (a station) moves from one Access Point to another (or BSS to
another) in the same Extended Service Set (ESS) -identified by its SSID.
root bridge
In
STP, 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.
root port
In
STP, the root port provides the shortest path to the root bridge.
All bridges except the root bridge contain one root port.
route
aggregation
In
BGP, you can combine the characteristics of several routes so they
are advertised as a single route, which reduces the size of the routing tables.
route flapping
A route is flapping
when it is repeatedly available, then unavailable, then available, then unavailable. In the
ExtremeXOS
BGP implementation, you can minimize the route
flapping using the route flap dampening feature.
route reflector
In
BGP, you can configure the routers within an
AS such that a single router serves as a central routing point for the entire
AS.
routing
confederation
In
BGP, you can configure a fully meshed
autonomous system into several sub-ASs and
group these sub-ASs into a routing confederation. Routing confederations help with the
scalability of BGP.
RP-SMA
Reverse
Polarity-Subminiature version A, a type of connector used with wireless antennas.
RSN
Robust Security Network. A new standard within IEEE 802.11 to provide security and
privacy mechanisms. The RSN (and related TSN) both specify IEEE 802.1x authentication with
Extensible Authentication Protocol (EAP).
RTS/CTS
RTS request to send,
CTS clear to send (in 802.11 standard).
RSTP
Rapid Spanning Tree
Protocol. RSTP, described in IEEE 802.1w, is an enhanced version of STP that provides faster
convergence. The Extreme Networks implementation of RSTP allows seamless interoperability with
legacy
STP.