Struck wid networking problem .

[farzi_baba]

In my lab there are 2 sub nets P and Q connected to switch S .now P has Host A and Q has host B . I observed the following strange data :

Ping time from A to B is 0.25 ms.(Avg Value)
Ping time from A to S is 89 ms.(Avg Value)
Ping time from B to S is 180 ms.(Avg Value)

A->B is much lesser than A->S and B->S and every
connection to A has to go through S. Shouldn’t the ping time from A->B greater than the
sum of ping times from A->S and S->B?

Network freaks any idea ? Totally struck :(

[ErikD]

Geezes, looks like a Calculus problem!

Well is that a multilayer switch? How are you getting from one subnet to the next? There will need to be something othter than a layer 2 packet forwarded at wire speed to get to a diferent subnet.

How are you getting 0.25ms? Most of the time this will just be <1ms if that is the case, not an exact vlaue. The values you are posting for time from workstation to switch are not all that unusual to me. What subnet is the switch on (management VLAN) or is this a multilayer switch with an IP interface in each subnet (VLAN).

Honestly to me it just seems like the switch is on the same subnet as A so it takes a little less time for a ping to go to the same subnet. The only really odd part is getting a decimal value as a time. Are you sure it isn't 25ms, then this owuld all make perfect sense and be normal network operarion (well maybe a bit slow for depending on utilization).