Some Thoughts on the Packet Network Architectur
Lixia Zhan · 2010
Performance control in packet switching networks is one of the remaining areas that are yet t o be explored . In this paper we look into the performance problems with two existing networ k architectures, datagram and virtual circuit . The major problem with the datagram network i s lack of effective traffic control ; and with the virtual circuit network, the improperly define d network control semantics and mechanisms . We consider that a new network architectur e should be investigated in order to provide performance support for diverse applications . 1 . Introductio n In packet switching computer communication networks, the network layer in the architectur e plays an important role . Its functionality is to deliver user data bits with specified performanc e requirements . Above it is the end-to-end transport layer residing in users' hosts . It is th e network layer, together with the layers below it, that physically carries out data transmissions . Its performance determines how good the network transmission services will be . Traffic congestion has been a major obstacle in achieving good network performance . Dat a from all sources are statistically multiplexed on shared network resources ; the moment-tomoment bandwidth requirement often varies dramatically . The network is designed to tolerat e modest traffic fluctuations, but not without limitation . Whenever a packet surge exceeds th e limit, it may congest one or more network switches and bring about disastrous consequences : creating long transmission delays, causing data losses, or even blocking up the network, breakin g down end users's connections . For example, the experience of running the ARPA Internet show s that congestion has been the major cause of network vulnerability . Among the problems remaining unsolved in packet switching networks, congestion control is perhaps one of the leas t understood [111 . Meanwhile, more and more new applications are being introduced into packet switchin g networks, such as real time voice, image data, and teleconferencing . These new application s