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EDA 1200 System Overview

• EDA Service Identification: Determine the EDA Service associated with

the frame. This uniquely identifies the Traffic Mapping Rules for the frame.

• Frame Validation: Is this a legal frame, or must it be discarded?

• Frame Modification: DHCP options, PPP, relay agent, VMAC, VLAN ID,

priority, and so on.

• Frame Forwarding: Send towards the right port, PVC, queue, and so on.

As Figure 16 on page 21 illustrates, each frame is first inspected in order to

identify the corresponding End-user (DSL) and EDA 1200 Service. Then, the

Access Node processes the frame according to the Traffic Mapping Rules. The

rules for each service are set when a service is defined.

The Traffic Mapping Rules can for example include filtering rules, allowing

only particular frame types or certain source/destination addresses. The rules

may also define how the frame is to be modified, for example appending of

DHCP options, adding or removing VLAN tags, changing source/destination

addresses, and marking or remarking of priority indication. Finally, the Traffic

Mapping Rules also define how frames associated with the EDA 1200 service

are to be forwarded, that is, towards a specific port, PVC, VLAN or queue.

Using these mechanisms, a virtual switch controls the traffic for each service.

3.1.2 Traffic Mapping Schemes

A Service VLAN is a VLAN in the Ethernet aggregation network that is used for

End-user traffic. The Service VLAN can be defined as either single or double

tagged VLAN. The End-user traffic may be separated by Service VLANs in

order to enhance network security, separate services, and reduce the size

of broadcast domains. The traffic in a Service VLAN can contain traffic from

several applications. For example, internet access, telephony and so on.

In order to map the traffic, each frame must be identified with respect to the

service to which it belongs. The way that the traffic is identified may be different

in the upstream and downstream. Downstream service identification is always

based on VLAN (single or double tagged). The following are the basic ways to

identify a service in the upstream direction:

• PVC or PVC bundle

• Ethertype (only supported by EDN312)

• VLAN ID

• Line

• IP destination (EFN324 only)

The following table shows the relations between Service identification and

drop technologies.

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APC IP DSLAM Guia do Utilizador Página 26