2.12.9 Dependencies

The SLS Rotation feature for vSTP has no dependency on any other vSTP operation.

The following points must be considered for SLS Rotation functionality:

• Usage of 5th bit as LSB for incoming bit rotation must be avoided if all the nodes are GR compliant. This is due to the fact that ANSI mandated outgoing 5 bit rotation causes the 5th bit to not have a uniform distribution of 0's and 1's.
• If 5 to 8 Bit Conversion is applied on incoming 5 bit SLS, then 3 new SLS bits (calculated based on the OPC) are prefixed to the 5-bit SLS. If all 8 SLS bits are considered for applying ISLSBR, the 3 new SLS bits become sticky bits and cause uneven distribution. In this scenario, ISLSRSB value 6-8 cause even more uneven distribution.
• If 5 bits SLS is received on incoming linkset, 5 to 8 bit conversion is OFF on outgoing linkset, and 8 bits SLS are considered for applying ISLSBR, then no rotation happens. The 5 to 8 Bit Conversion option must be turned ON to perform ISLSBR.
• When two linksets are used as a combined linkset, they should have the same settings for all SLS algorithms (For example, Other CIC Bit, Rotated SLS Bit), otherwise there can be a random behavior. This is not enforced in vSTP , and there is no warning mechanism for incorrectly provisioned linksets and routes.
• Different RANDSLS configurations on two linksets , which happen to be a part of combined linkset for the routes defined for a destination node may result in undesired SLS distribution. vSTP does not prompt or reject the linkset provisioning command if the provisioning is done contrary to the above.
• For different segments of the same MSU, randsls generates different SLS and different link selection. For other SLS algorithms, it is assumed that the Incoming linkId or SLS is same for different segments of the same MSU, hence the outgoing linkId or linkset id will be same for different segments of the same MSU.