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JUNOS 10.1 Network Interfaces Configuration Guide
Mobile Backhaul Application Overview
This section provides an application example (see Figure 49 on page 530) based on
the mobile backhaul reference model where customer edge 1 (CE1) is a base station
controller (BSC), Provider Edge 1 (PE1) is a cell site router, PE2 is an M Series
(aggregation) router, and CE2 is a BSC and Radio Network Controller (RNC). The
Internet Engineering Task Force (RFC 3895) describes pseudowire as "a mechanism
that emulates the essential attributes of a telecommunications service (such as a T1
leased line or Frame Relay) over a PSN" (Packet Switching Network).
Figure 49: Mobile Backhaul Application
Attachment Circuit
CE1
Native service
Understanding Circuit Emulation PIC Types
The following Circuit Emulation PICs are specifically designed for mobile backhaul
applications:
The four-port Channelized OC3/STM1 Circuit Emulation PIC allows each of its four
ports to be independently configured to either SONET or SDH framing mode, and
supports mixed SAToP and ATM interfaces on any port. In SONET mode, each OC3
port can be channelized down to 3 coc1 channels, and then each coc1 can channel
down to 28 T1 channels. In SDH mode, each STM1 port can be channelized down
to 4 cau4 channels, and then each cau4 can channel down to 63 E1 channels. The
T1/E1 channels support time-division multiplexing (TDM) interfaces using the
Structure-Agnostic time-division multiplexing over Packet (SAToP) protocol [RFC
4553] encapsulation, and support T1/E1 and SONET clocking features. Mixing T1
and E1 channels is not supported on individual ports.
The 12-port Channelized T1/E1 Circuit Emulation PIC supports TDM interfaces using
the SAToP protocol [RFC 4553] encapsulation, and supports T1/E1 and SONET
clocking features. The 12-port Channelized T1/E1 Circuit Emulation PIC can be
configured to work as either 12 T1s or 12 E1s. Mixing T1s and E1s is not supported.
530
Mobile Backhaul Application Overview
Emulated Service
PSN tunnel
Pseudowire 1
PE1
Pseudowire 2
4-port Channelized OC3/STM1 Circuit Emulation PIC
12-port T1/E1 Circuit Emulation PIC
Attachment Circuit
PE2
Native service
CE2
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