Netramet Sample Clauses

Netramet. ‌ Netramet is an implementation of the Meter MIB [RFC2720] defined by the IETF Real-time Traffic Flow Measurement working group. This working group has completed this work, and is therefore no longer an active working group. A record of the output of this group is still available elsewhere [RT- FM]. The basic architecture of a RTFM traffic flow measurement system consists of three basic building blocks: • Meters gather data about packets and condense this data into ‘flow data’. • Meter Readers retrieve flow data from meters using the SNMP protocol. • Managers co-ordinate the activities of the meters and the meter readers. The basic operation of the system involves the creation of rulesets. Each rule in a ruleset defines the criteria that determine which packets belongs to which flow. Any information that is available in the IP packet header can be used for this, so rules can look at source IP address, destination IP address, source and destination port numbers, protocol identifiers (TCP, UDP, ICMP) and so on. A flow is de- fined in the NeTraMet manual as The rulesets can be descibed in the native format that NeTraMet uses, or they can be written in a higher level language called the Simple Rule Language [SRL] and then compiled into the native for- mat. The manager downloads the ruleset into the meter, and the process of matching packets against the ruleset and counting the packets in each individual flow begins. The network card is put into promis- cuous mode, so that every packet in the complete broadcast domain is examined by the NeTraMet software. Each arriving packet is matched against the rules in a rule set, and if it matches, it belongs to a flow. If a flow did not exist, a ‘record’ for it is created. As long as new packets arrive within the flow time-out value, the flow stays in existence, otherwise, it is closed. The meter readers gather the data from the meters at regular intervals for further processing. A sep- arate program called nifty is available that provides a near-Real-time graphical view on the measured flows in a ruleset. It is in the processing step in the meter reader that the actual SLA parameter verification has to take place.