Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Tue, Jan 30, 2007 at 02:08:07PM +0100, Lars Ellenberg wrote: > also note that rtt in LAN is usually orders of magnitude > less than average seek time/fsync time of storage. > also in a dedicated fo for over 20km, > rtt might be in the order of one digit ms, iirc. Gigabit local linux<-switch-2x10Gig fiber 500m-switch->linux (l2 switch = cisco) 64 bytes from 10.41.0.1: icmp_seq=1 ttl=64 time=0.202 ms 64 bytes from 10.41.0.1: icmp_seq=2 ttl=64 time=0.251 ms 64 bytes from 10.41.0.1: icmp_seq=3 ttl=64 time=0.203 ms Gigabit local linux<->cisco (l2 switch/router = cisco) 64 bytes from 10.53.254.4: icmp_seq=1 ttl=255 time=0.363 ms 64 bytes from 10.53.254.4: icmp_seq=2 ttl=255 time=0.559 ms 64 bytes from 10.53.254.4: icmp_seq=3 ttl=255 time=0.366 ms Gigabit routed linux<-switch/router-(10Gig fiber>30km)->cisco (l3 router = cisco) 64 bytes from 217.196.40.69: icmp_seq=1 ttl=254 time=0.618 ms 64 bytes from 217.196.40.69: icmp_seq=2 ttl=254 time=0.541 ms 64 bytes from 217.196.40.69: icmp_seq=3 ttl=254 time=0.593 ms So if you carefully look at the roundtrip times: the distance of the fiber really doesn't matter that much, only the number of hops. A cisco ping roundtrip is longer, since cisco handles icmp's destined for it at a low priority.