An interview with the accounting specialist at SWITCH, Zürich, namely Simon Leinen revealed clearly that detailed knowledge about the network and traffic is required to determine the real problems of accounting in case of high/higher speeds. The long-term problems will be the increase of the average volume per flow, in which the number of flows determine only a minor aspect, however, in case of the technology used, the storage limitations for per-flow information in routers management plane will be challenging. While stateful middleboxes seem to disrupt the pure founder’s notion of the Internet, a newer problem with very, very many mobile devices and their accounting in the connection-less case will manifest. Special hardware for un-sampled flows is yet seldomly found, but special requirements are partially known today. Thus, CISCO’s newly announced Switching engines with the capability of one million flows being handled per line card (ingress and egress) point to the right direction. However, many so called carrier-class routers use sampled NetFlow, in which 1 out of 1000 packets are sampled in software, which results in the lack of detailed knowledge. |
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