The Johns Hopkins University Applied Physics Laboratory This document extends the Bundle Protocol Endpoint ID (EID) concept into an EID Pattern, which is used to categorize any EID as matching a specific pattern or not. EID Patterns are suitable for expressing configuration, for being used on-the-wire by protocols, and for being easily understandable by a layperson. EID Patterns include scheme- specific optimizations for expressing set membership and each scheme pattern includes text and binary encoding forms; the pattern for the "ipn" EID scheme being designed to be highly compressible in its binary form. This document also defines a Public Key Infrastructure Using X.509 (PKIX) Other Name form to contain an EID Pattern and a handling rule to use a pattern to match an EID.