ination out of order, whereas others might get lost on their way for many reasons, such as looping around folded branches or timing out. They could also end up being misforwarded by an incorrectly configured router. We will soon see how the industry started looking after these legitimate QoS concerns. However, first we will take a look at how the industry came to the (then) unbelievable point of being able to fully and reliably manage complex network gear from a distance. NETWORK MANAGEMENT The proliferation of interconnected devices would have created a nightmare of unprecedented pro- portions had the techniques that enable the remote management of network devices not been invented. One of the major breakthroughs that enhanced network management was the protocol analyzer, which allowed network engineers to tap onto problematic network segments and analyze the frames until the cause of the problem was identified and fixed. The undisputable revolution in network management, however, has to be ascribed to the Simple Network Management Protocol (SNMP) protocol. 13,14 SNMP was developed by the IETF. It is a soft- ware system that is predominantly based inside a PC or a UNIX system in the network management station. This station is able to communicate automatically with the various devices deployed across a network to collect information and therefore detect problems or issues that may require attention. 10. Christian Huitema, Routing in the Internet (Upper-Saddle River, New Jersey: Prentice-Hall, 2000). 11. Uyless Black, IP Routing Protocols: RIP, OSPF, BGP, PNNI, and Cisco Routing Protocols (Upper-Saddle River, New Jersey: Prentice-Hall, 2000). 12. Radia Perlman, Interconnections: Bridges, Routers, Switches, and Internetworking Protocols, 2nd ed. (Reading, Massachusetts: Addison-Wesley, 1999). 13. William Stallings, SNMP, SNMPv2, SNMPv3, and RMON 1 and 2 (Reading, Massachusetts: Addison-Wesley, 1999). 14. David Perkins and Evan McGinnis, Understanding SNMP MIBs (Upper Saddle River, New Jersey: Prentice-Hall, 1996). 