NDACC recognizes the importance of new measurement capabilities and of existing capabilities whose heritage was developed external to NDACC, and has encouraged Network affiliation with such measurements. In some cases, there are regional, hemispheric, or even global networks of instruments that operate independently of NDACC, but where strong measurement and scientific collaboration would be mutually beneficial. Such networks often have set up their own quality-assurance guidelines, operational requirements, and data archiving policies, and they have national or international recognition in their own right. In such cases, bringing the complete network under the NDACC umbrella is neither practical nor desirable. Rather, designation of an interested external network as a "Cooperating Network" may be more appropriate, and can foster collaborative measurement and analysis activities. For such designation to occur, the relevant NDACC Working Group must assess the benefits of mutual data access. The Working Group should further ascertain that the various protocols of the external network are compatible with those of NDACC, and are followed consistently and effectively. A protocol detailing the specific process whereby such affiliation can occur is posted on the NDACC web site.