Most ATM switches come from the factory with default ATM addresses. If you'll never connect your switches to the outside world, these default addresses are fine. However, if you're planning to interconnect with others or may do so at a later time, you should assign "public" ATM addresses. You can do this using three formats: the Data Country Code (DCC) format; the E.194 format and the International Code Designator (ICD) format. To setup ATM addressing using the DCC format, you need what is called the NSAP organization ID. This is assigned in Canada by a grouped called the Canadian OSI Registration Authority (COSIRA).

To setup your ATM address, you'd follow this format:

39.12.4F.81.xx.xx.xx.aa.bb.cc.dd.ee.ff

• 39 means that the ATM address is in DCC format
• 12.4F means it's a Canadian address
• 81 means it's assigned by COSIRA
• xx.xx.xx is the Org ID assigned to you by COSIRA (they will give you a decimal number, which has to be converted to hex)
• aa.bb.cc.dd.ee.ff is the piece that you get to assign yourself.

This is one way you could use it:

• aa is the Country
• bb is the site or city
• cc.dd is the building
• ee is the floor
• ff is the node

You also have to define the routing prefix, which is similar to an IP subnet mask. As an example if you set the routing prefix to 72 (bits) the ATM network "routes" based on this part:

39.12.4F.81.xx.xx.xx.aa.bb