Specifications

Chapter 1 Introduction Installation and Operation Manual

1-10 Functional Description ASMi-54C LRS-102 Ver. 2.0

Ethernet Traffic Processor

Each Ethernet traffic processor provides four independently-configurable Physical

Coding Sublayers (PCSs as defined in IEEE 802.3-2005), one for each SHDSL line

in the corresponding group (1 to 4 or 5 to 8). In IEEE 802.3-2005 terminology,

each PCS is associated with a PME (Physical Medium Entity): for ASMi-54C

modules, the PME is an SHDSL line (when using the M-pair mode, the PME is the

SHDSL master line).

The main functions performed for each PCS include:

• Ethernet payload data rate matching: the average payload rate accepted by

each PCS is matched to the physical rate supported by the corresponding

PME.

• PAF (PME Aggregation Function), defined in IEEE 802.3-2005. PAF creates

PCS groups (two or four, as selected by the user) that enable increasing the

available bandwidth when using the 64/65-octet TC layer. As for M-pair

bonding, one of the PCSs (the PCS with the lowest index in the group) is

automatically selected as the master PCS, from which all the other PCSs copy

their parameters.

• TC encapsulation, in accordance with the user-selected mode (64/65-octet

or HDLC).

Each active PCS can serve as a bridge port that can terminate Ethernet flows.

Ethernet Subsystem

ASMi-54C Ethernet services are supported by configuring flows within the

LRS-102 (flows are a generic type of Ethernet virtual connections that

interconnect user-specified bridge ports). For an overview of Ethernet services,

refer to the

LRS-102 Installation and Operation Manual

Two types of bridge ports can be defined on an ASMi-54C module:

• Each PCS configured on the module SHDSL ports.

• Each Ethernet physical port can also serve as a bridge port.

The maximum number of bridge ports that can be defined on an ASMi-54C

module, together with the two Ethernet ports, is up to 10.

ASMi-54C Ethernet Handling Subsystem

The functional block diagram of the ASMi-54C local Ethernet handling subsystem

is shown in

Figure

1-3

. This subsystem includes:

• Ethernet port interfaces: provide 10/100 Mbps physical interfaces for

external Ethernet links.

• Main layer 2 Ethernet switch: provides the local Ethernet classification and

switching functions. The Ethernet switch determines the destination of each

frame in accordance with the configured flows. The classification of each

user network is based on the VLAN ID, or on the port, if no C-VLAN is

configured.

Not