Pseudowire Emulation Over Packet; Circuit Emulation Services Over Packet Switched Network Over Udp - Cisco ASR 900 Series Manual

Circuit Emulation Service over UDP
CES allows you to interconnect existing T1 or E1 interfaces and other kinds of CBR equipment. CES includes
features such as PBX interconnect, consolidated voice and data traffic, and video conferencing.
With circuit emulation, data received from an external device at the edge of an ATM network is converted to
ATM cells, sent through the network, reassembled into a bit stream, and passed out of the ATM network to
its destination. T1/E1 circuit emulation does not interpret the contents of the data stream. All the bits flowing
into the input edge port of the ATM network are reproduced at one corresponding output edge port.
An emulated circuit is carried across the ATM network on a PVC, which is configured through the network
management system or the router command line interface (CLI).

Pseudowire Emulation over Packet

Pseudowire Emulation over Packet (PWEoP) is one of the key components that you can use to migrate to a
packet-based multi-service network. Circuit Emulation over Packet (CEoP) is a subset of PWEoP. It is used
to migrate to all-packet networks from legacy TDM networks, yet providing transport for legacy applications
transparently over a packet network. CEoP is the imitation of a physical connection. Many service providers
and enterprises operate both packet switched networks and TDM networks. These service providers and
enterprises have moved many of their data services from the TDM network to their packet network for
scalability and efficiency. Cisco provides routing and switching solutions capable of transporting Layer 2 and
Layer 3 protocols such as Ethernet, IP, and Frame Relay. Most applications and services have been migrated
to the packet-based network, including voice and legacy applications.

Circuit Emulation Services over Packet Switched Network over UDP

CESoPSN mode is used to encapsulate T1/E1 structured (channelized) services over PSN. Also referred to
as structured mode, CESoPSN identifies framing and sends only payload, which can be channelized T1s
within DS3 and DS0s within T1. DS0s can be bundled to the same packet. This mode is based on IETF RFC
5086.
UDP acts as transport mechanism over IP for CESoPSN.
Each supported interface can be configured individually to any supported mode. The supported services
comply with IETF and ITU drafts and standards.
The figure below shows the frame format in CESoPSN mode.
Figure 12: Structured Mode Frame Format
MPLS Basic Configuration Guide, Cisco IOS XE Everest 16.5.1 (Cisco ASR 900 Series)
Pseudowire Emulation over Packet
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