PDH Interface

In a PSN network, the PDH interfaces can be used to carry TDM signals, IMA signals, or tunnels, depending on different settings of the interface attributes. The attributes of a PDH interface include the basic attributes, Layer 2 attributes, Layer 3 attributes and advanced attributes.

Guideline

The application scenario of a PDH interface depends on the setting of the interface attributes. For details, refer to Table 1.

**Table 1** Application scenario of PDH interfaces
Application Scenario	Interface Type	Required Interface Attribute
Carrying the CES service	E1 interface	Basic Attributes, Advanced attributes
Carrying the ATM service	E1 interface	Basic Attributes, Layer 2 attributes
Carrying the tunnel	E1 interface	Basic Attributes, Layer 3 attributes

NOTE:

When the E1 interface is used to carry the CES service, set the basic attributes and an advanced attribute, that is, frame format, to ensure that the frame format is the same as the service encapsulation format. When the emulation mode of a CES service is CESoPSN, it is recommended that you set the frame format at the interface to CRC-4 multiframe. When the emulation mode of a CES service is SAToP, the frame format at the interface should be set to non-framing.

When the E1 interface is used to carry the ATM service, the Layer 2 attributes should be set. In addition, the IMA group should be created. When setting the Layer 2 attributes of the E1 interface, set Port Mode to Layer 2 in Basic Attributes.

When the E1 interface is used to carry the tunnels, the Layer 3 attributes should be set. In addition, create the ML-PPP group, and configure the interface as an ML-PPP member.

Follow the procedure shown in Figure 1 to configure a PDH interface.

Figure 1 Procedure for configuring a PDH interface