Date: Sun, 30 Aug 2009 21:04:15 +0900 From: Randy Bush <randy@psg.com>
If your 95th percentile utilization is at 80% capacity, it's time to start planning the upgrade.
s/80/60/
the normal snmp and other averaging methods *really* miss the bursts.
s/60/40/ If you need to carry large TCP flows, say 2Gbps on a 10GE, dropping even a single packet due to congestion is unacceptable. Even with fast recovery, the average transmission rate will take a noticeable dip on every drop and even a drop rate under 1% will slow the flow dramatically. The point is, what is acceptable for one traffic profile may be unacceptable for another. Mail and web browsing are generally unaffected by light congestion. Other applications are not so forgiving. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751