R3303-HP HSR6800 Routers Interface Configuration Guide

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Similar to the J0 byte, the higher-order VC-N path trace byte J1 is included in the higher-order path
overhead to repeatedly send the higher-order path access point identifier, based on which the receiving
end of the path can make sure it is in continuous connection with the specified sender. The sender and
the recipient must use the same J1 byte.
In addition, the path signal label byte C2 is included in the higher-order path overhead to indicate the
multiplexing structure of VC frames and the properties of payload such as whether the path is carrying
traffic, what type of traffic are carried, and how they are mapped. The sender and receiver must use the
same C2 byte.
CPOS interface application scenario
CPOS is used to enhance the capability of a device in low-speed access redistribution. STM-1 CPOS is
especially suitable for aggregating E1/T1 channels.
Some government agencies and enterprises use low-end and mid-range devices to access transmission
networks through E1/T1 leased lines. Users who require bandwidth between E1 and T3 (44 Mbps), for
a data center for example, lease multiple E1/T1 lines.
The bandwidth of all these users is aggregated to one or more CPOS interfaces through a transmission
network, and then connected to a high-end device where the low-end devices are uniquely identified by
timeslots.
In actual applications, the connection between these low-end devices and the CPOS interfaces might
span more than one transmission network and as such, might require relay. This is similar to the scenario
where low-end devices are connected to a high-end device through one or multiple E1/T1 leased lines.
Figure 14 Network diagram for a CPOS application
Configuring a CPOS interface
Follow these guidelines when you configure a CPOS interface:
• E1 configuration is supported on the CPOS(E) interface module but T1 configuration is supported
on the CPOS (T) interface module.
• If no cable is connected to a physical interface, shut down the interface with the shutdown
command to prevent anomalies caused by interference.
• Use the shutdown command with caution, because once an interface is shut down, it stops
operating.