Sub-Network Connection (SNC)
a TE that represents a connection between two points inside the network. Additional configuration must be added in order to complete the path necessary for traffic to pass.
The FOXMAN-UN NP can generate SNC for the following reasons:
• Loss of connectivity inside the network.
In this situation there is a missing cross connection within the network.
Example: a LESU1 port at P0_nc is cross connected with a LEDE1 port in one FOX61x of the network. On the remote FOX61x there is no cross connection between the transmission card and LESU1 at P0_nc.
• Missing sections in the FOXMAN-UN BP can also lead to SNCs.
The upper graphic of The missing Section in FOXMAN-UN BP shows the NP recognizes one TE (Circuit). If the second Section is missing, then the FOXMAN-UN NP will then recognize two TEs of type SNC.
The missing Section in FOXMAN-UN BP
• Broadcast configuration.
Any broadcast configuration will generate one or more SNCs (depending on the broadcast configuration). For more details, please refer section Broadcast Constructs.
• P0_nc connection point shared into Nx64 kbit/s connection points.
e.g. FOX61x allows to cross connect a P0_nc port (LEDS1 at 128 kbit/s) into two 64 kbit/s ports (LEDS1 port at 64 kbit/s or a 64 kbit/s G.703 port).
This configuration starting at P0_nc and ending at P0 layer leads to an SNC.
• FO Tool configuration files not complete.
There are NEs of type FO configurations files in the FOXMAN-UN NP:
the npfotool_termination.csv file defines all the NEs of type FO names used for terminated circuit connectivity, the npfotool_trailhierarchy.csv specifies which FO/MUX section should be completed with missing multiplexing rates and the npfotool_crossconnect.csv file defines the cross-connections within all the NEs of type FO.
If any information is missing in one of these files then a SNC will be generated.
• Incorrect SNCs in the FOXMAN-UN NP.
SNC may exist in the network before FOXMAN-UN NP analyses the FOX51x or FOX61x network and the NEs of type FO. After the FOXMAN-UN NP network analysis, all the SNCs used in Trails and in terminated Circuits or in cross-connection through FO should be removed and replaced by Trails and Circuits. In other words, if a Circuit uses a SNC, then the SNC should be removed automatically.
• NE of type FO internal connections are SNCs.