Overview; Frame Processing Overview - FibroLAN Falcon-RX/812/G/A User Manual

Falcon R-Class | User Guide
4 Functional Description

4.1 Overview

This section provides introduction to the R Class series functionality and instructions for
configuration and monitoring.
The configuration and monitoring functionalities can be accessed via various management
interfaces. Sections 4 demonstrates the configuration various functions and setting mainly using the
Web interface. However, any configuration can be implemented using other management interfaces
(CLI, Telnet, and SNMP).

4.2 Frame Processing Overview

This section provides a general description of the Frame Forwarding Process at the R Class series
from the input port toward the output port, as illustrated below.
Figure 4-1: Frame Forwarding Diagram
Input frame flow
Frames received on the input port (MAC layer) are handed to the classifiers in order to classify frames
into different flows (e.g., management frames, specific service/user frames, etc.). Following the
classification, the frames are passed to the Policer. If the Policer is not selected the frames pass
untouched. From the Policer the frames enter the Ingress Queue. Some prioritization algorithms are
used to handle traffic and to avoid buffer overrun and Frame loss.
Output frame flow
The frames, which pass from the Ingress Queue, are transferred to the Egress Queue (8 parallel
queues). The topmost queue handles management frames injected by the CPU, which have super
priority over the other four queues. The remaining queues transfer data frames. At this stage, a
scheduling process is taking place in order to decide which frame will be sent out of the port (out of
the 8 candidate queues). For scheduling either a Strict-Priority or a Weighted Fair Queuing algorithm
is being used. The output of the queue is passed to the Shaper. If the Shaper is not selected the frame
passes untouched. The frames are then passed to the Rewriter. The Rewriter examines the frame
header information and adjusts it if required. From there on the frame is sent to the output port
(MAC layer).
Packet forwarding
Packet forwarding decisions are based on the following criteria:
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