Interconnecting LANs and MANs to ATM

One of the challenges in the interconnection of LANs and MANs to ATM is the support of connectionless traffic in the ATM network. Several solutions have been proposed. A popular strategy seems to be that of maintaining a 'thin' (i.e. low bandwidth) VP (virtual path) between each pair of gateways, and of requesting more bandwidth whenever a burst comes in from the LAN or MAN. Unfortunately, this strategy places a heavy burden on the ATM control processors; furthermore, it is overly conservative in the use of bandwidth. An alternative solution is proposed: on-the-fly transmission of bursts, without prior bandwidth reservation. The key conditions for this scheme to work are the use of the CLP (cell loss priority) bit, and the knowledge of available bandwidth on the path through 'bandwidth advertising'. An 'on-the-fly' strategy for connectionless traffic is described and is compared with a bandwidth renegotiation strategy.<
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