The Integrated Services Digital Network (ISDN) Q.921-User Adaptation Layer
(IUA) protocol described in RFC4233 defines the messages type of Terminal
Endpoint Identifier (TEI) Query Request messages as 5. But this number is
already used by the Digital Private Network Signaling System
(DPNSS)/Digital Access Signaling System 2 (DASS 2) Extensions (DUA) to the
IUA Protocol described in RFC4129. This document updates RFC4233 such that
the message type of TEI Query Request messages is 8.