Cisco Systems A9014CFD manual Understanding Pseudowires, Structure-Agnostic TDM over Packet, 21-2

Chapter 21 Configuring Pseudowire

Understanding Pseudowires

Figure 21-1 Cisco ASR 901 Router in a PWE3—Example

TDM xconnect xconnect

MPLS/IP

Pseudowire

Emulated Circuit

TDM

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Understanding Pseudowires

Pseudowires (PWs) manage encapsulation, timing, order, and other operations in order to make it transparent to users; the PW tunnel appears as an unshared link or circuit of the emulated service.

There are limitations that impede some applications from utilizing a PW connection.

Cisco supports the following standards-based PWE types:

•Structure-Agnostic TDM over Packet, page 21-2

•Structure-Aware TDM Circuit Emulation Service over Packet-Switched Network, page 21-3

•Transportation of Service Using Ethernet over MPLS, page 21-3

Structure-Agnostic TDM over Packet

SAToP encapsulates TDM bit-streams (T1, E1, T3, E3) as PWs over PSNs. It disregards any structure that may be imposed on streams, in particular the structure imposed by the standard TDM framing. The protocol used for emulation of these services does not depend on the method in which attachment circuits are delivered to the PEs. For example, a T1 attachment circuit is treated the same way for all delivery methods, including: PE on copper, multiplex in a T3 circuit, mapped into a virtual tributary of a SONET/SDH circuit, or carried over a network using unstructured Circuit Emulation Service (CES). Termination of specific carrier layers used between the PE and circuit emulation (CE) is performed by an appropriate network service provider (NSP).

For instructions on how to configure SAToP, see Configuring Structure-Agnostic TDM over Packet, page 21-9.

For a sample SAToP configuration, see Configuration Examples for Pseudowire, page 21-31.

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
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