ApsK1K2
This Textual Convention describes an object that contains the K1 and K2 bytes in the SONET APS channel protocol message field. K1 is located in the first octet. Bits 1-4 of the K1 byte indicate a request. 1111 Lockout of Protection 1110 Forced Switch 1101 SF - High Priority 1100 SF - Low Priority 1011 SD - High Priority 1010 SD - Low Priority 1001 not used 1000 Manual Switch 0111 not used 0110 Wait-to-Restore 0101 not used 0100 Exercise 0011 not used 0010 Reverse Request 0001 Do Not Revert 0000 No Request Bits 5-8 of the K1 byte indicate the channel associated with the request defined in bits 1-4. 0 is the Null channel 1-14 are working channels. 15 is the extra traffic channel K2 is located in the second octet. Bits 1-4 of the K2 byte indicate a channel. The channel is defined with the same syntax as K1 Bits 5-8. Bits 5 of the K2 byte indicates the architecture. 0 if the architecture is 1+1 1 if the architecture is 1:n Bits 6-8 of the K2 byte indicates the mode. 000 - 011 are reserved for future use 100 indicates the mode is unidirectional 101 indicates the mode is bidirectional 110 RDI-L 111 AIS-L