Hi Ajaz,

I'm not sure that there is a typical number of CSS's as this depends on the requirements and level of restrictions one may need. There are some really thoughtful "Best Practice" design ideas below;

"Use concise and descriptive names for your partitions. The CompanynameLocationCalltype format usually provides a sufficient level of detail and is short enough to enable you to quickly and easily identify a partition. For example, CiscoDallasMetroPT identifies a partition for toll-free, inter-local access and transport area (LATA) calls from the Cisco office in Dallas."

And for CSS;

The CompanynameLocationCalltype format usually provides a sufficient level of detail and is short enough to enable you to quickly and easily identify a calling search space. For example, CiscoDallasMetroCS identifies a calling search space for toll-free, inter-local access and transport area (LATA) calls from the Cisco office in Dallas.

From this doc;

Partition Configuration Settings

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a0080181a46.html#26766

There are some nice ideas in this doc;

Understanding and Using Partitions and Calling Search Spaces with Cisco CallManager

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a0080094b53.shtml

And this interactive link;

Voice Dial Plan Interactive Voice Network Configuration Example

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a00807f54af.shtml

Hope this helps!

Rob