RFC 2721 (rfc2721) - Page 3 of 10
RTFM: Applicability Statement
Alternative Format: Original Text Document
RFC 2721 RTFM: Applicability Statement October 1999
[RTFM-NEW] RTFM New Attributes (Experimental)
There has been considerable interest from users in extending the
RTFM Architecture so as to allow a meter to report on an increased
number of flow-related measures. This RFC documents work on
specifying such measures (the 'new' attributes) and reports on
experience of implementing them.
[RTFM-NTM] RTFM: Experiences with NeTraMet (Informational)
NeTraMet is a free software implementation of the RTFM
Architecture which has been available since 1993. This RFC
records RTFM implementation experience gained with NeTraMet up to
late 1996. One particularly important result is the realisation
that groups of rules which test the same attribute using the same
mask can be implemented as a single hashed comparison, allowing
the meter to rapidly determine whether a packet belongs to one of
a large number of networks.
2 Brief Technical Specification (TS)
RTFM provides for the measurement of network traffic 'flows', i.e.
- a method of specifying traffic flows within a network
- a hierarchy of devices (meters, meter readers, managers) for
measuring the specified flows
- a mechanism for configuring meters and meter readers, and for
collecting the flow data from remote meters
RTFM provides high time resolution for flow first- and last-packet
times. Counters for long-duration flows may be read at intervals
determined by a manager. The RTFM Meter is designed so as to do as
much data reduction work as possible, which minimizes the amount of
data to be read and the amount of processing needed to produce useful
reports from it.
RTFM flow data can be used for a wide range of purposes, such as
usage accounting, long-term recording of network usage (classified by
IP address attributes) and real-time analysis of traffic flows at
remote metering points.
3 Applicability Statement (AS)
To use RTFM for collecting network traffic information one must first
consider where in the network traffic flows are to be measured. Once
that is decided, an RTFM Meter must be installed at each chosen
measurement point.
Brownlee Informational