Loop Detection Mechanisms for Session Initiation Protocol (SIP) Back-to-Back User Agents (B2BUAs)
SIP Back-to-Back User Agents (B2BUAs) can cause unending SIP request routing loops because, as User Agent Clients, they can generate SIP requests with new Max-Forwards values. This document discusses the difficulties associated with loop detection for B2BUAs and the requirements for them to prevent infinite loops.