Networking Explained, 2nd Edition

Chapter 12: Frame Relay 389

enough), then data transmissions are not guaranteed. Thus, the assignment of a CIR to a

PVC is extremely critical to both network cost and performance. If a PVC’s CIR is too lit-

tle, then when the network becomes congested, frames may be dropped. On the other

hand, if the CIR is too high, then you are paying for excessive bandwidth. This is analo-

gous to the way banks calculate the monthly maintenance fee of a checking account. If the

monthly average of the funds in the account is less than a prescribed minimum, then a fee

is assessed. If, however, the monthly average grossly exceeds the minimum average, then

you probably ...