Correct, there is no hard limit how many CSS you can have, only the limit of partitions within a CSS (driven by number of characters in partition name). From CUCM SRND v.9:
The maximum length of the combined calling search space (device plus line) is 1024 characters,
including separator characters between each partition name. (For example, the string
“partition_1:partition_2:partition_3” contains 35 characters.) Thus, the maximum number of partitions
in a calling search space varies, depending on the length of the partition names. Also, because the calling
search space clause combines the calling search space of the device and that of the line, the maximum
character limit for an individual calling search space is 512 (half of the combined calling search space
clause limit of 1024 characters).
Therefore, when you are creating partitions and calling search spaces, keep the names of partitions short
relative to the number of partitions that you plan to include in a calling search space.
HTH,
Chris
