eligible. The question remains, though: How do you know what is being discarded and how
often by the provider? Does 50 percent of the traffic make it? Does 100 percent of the traffic
make it?
beneficial to not look for the DEs because that becomes time-consuming for the switches. That
means that there is no policing mechanism, and everybody's traffic is treated exactly the same
way. It might depend on your carrier.
sites can burst to 128 K, there are other issues. The combination of all the remote sites together
bursting over the 64 K CIR results in too much data for the central site T1 to handle. This is
common with Frame Relay; it's called oversubscription. You can risk oversubscription and
simply assume that all the remote sites will not be busy at the same time. Most of the time, the
traffic will get through, but this is a risk that needs to be thought out. For example, if the
company sites are spread out around the world, the company can assume that due to the time
differences between sites, some sites won't be very active at certain times because most work
is performed between 8 a.m. and 5 p.m. at all the sites. The company can risk oversubscribing
and feel confident that it will not cause any problems.
time. Therefore, the more the measurements and the shorter their duration, the more accurate
they are. If I have a CIR of 128 Kbps, would that mean the provider could provide for 32 Kbps
in the first half-second and provide for 96 kbps in the second half-second, equaling 128 K, and
thus and I'd meet my 128 K requirement for 1 second? No, this is where the measurement
interval comes into play.
I would have a CIR of 8 K every eighth of a second. This provides for more accuracy.
Obviously, the more often you measure, the greater the chance that you'll get what you paid for.
For example, if a measurement is made every sixteenth of a second, the provider needs to
provide 4 K for a CIR of 64 K. Thus, it might be important to discuss how often your provider
measures the intervals. If you hear "one-half second" in the same sentence you hear
"measurement interval," you might want to reconsider your provider.