Specifications

Chapter 1 Introduction Installation and Operation Manual
1-6 Functional Description RICi-622GE Ver. 1.0
1.3 Functional Description
Traffic Flow
Figure 1-4 illustrates the traffic handling process. Table 1-1 provides an overview
of the traffic handling stages.
Egress
Processing and
Shaping
Scheduling
Mapping to Queues,
Congestion Avoidance,
Counters
Policing
Traffic
Classification
and Forwarding
Traffic Filtering
Figure 1-4. Traffic Handling Diagram
Table
1-1. Traffic Handling Stages
Processing Stage Description
Traffic filtering Performing MAC filtering (ACL), CE-VLAN filtering, MAC limitation
Traffic classification Creating EVC or EVC.CoS accrding to CE-VLAN, P-bit
2R3C policing Applying CIR+CBS,EIR+EBS per EVC/EVC.cos
Mapping to queues,
congestion avoidance,
counters
Mapping EVC/EVC.CoS to 5 queues (1 SPQ + 4 WFQ)
Applying congestion avoidance techniques
Activating counters per EVC/EVC.CoS
Scheduling Dequeuing traffic from SPQs and WFQs
Egress processing,
egress shaping
Priority (S-Tag) marking
Egress port shaping
Encapsulation
RICi-622GE supports the following encapsulation protocols:
• Link Access Protocol (LAPS) for SDH/SONET in accordance with
ITU-T Rec. X.86 draft recommendations
• Generic Framing Procedure (GFP) in accordance with ITU-T Rec. G.7041,
ANSI T1-105.02, framed mode.
LAPS Encapsulation
With LAPS, each Ethernet frame is encapsulated in the frame structure shown in
Figure 1-5 . The LAPS frame is delineated by flags, followed by HDLC information
(address and control), and by a LAPS service access point identifier (SAPI). The
Ethernet frame is followed by a LAPS frame checksum (FCS), for error detection.
LAPS Frame
Ethernet Frame
Flag
HDLC
Address
HDLC
Control
LAPS SAPI Ethernet Frame LAPS FCS Flag