Question : How to calculate OSPF cost?

Hi

i need to know how to calculate OSPF cost i mean suppose i put this command in both routers which are connected to each others using FastEthernet  

bandwidth 5120

i thought cost would be 100/5120=51 but when issued sh ip ospf interface command i came to know it was showing 19 after reloading router

what cost shold be and how you calculate it?


Thanks++

Answer : How to calculate OSPF cost?

point to point T1 serial interfaces with no bandwidth command
Bandwidth = 1544000bps (1.5Mbps)

100000000/1544000 = 64
OSPF Cost = 64


Point to point T1 serial interface with the bandwidth command
Bandwidth = 64000

100000000/64000 = 1562
OSPF Cost = 1562


======================

dist01.lax01#show int ser1/0 | inc BW
  MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
dist01.lax01#show ip ospf int ser1/0 | inc Cost
  Process ID 100, Router ID 64.100.34.2, Network Type POINT_TO_POINT, Cost: 64
  Topology-MTID    Cost    Disabled    Shutdown      Topology Name
dist01.lax01#show int ser1/0 | inc BW
  MTU 1500 bytes, BW 64 Kbit/sec, DLY 20000 usec,
dist01.lax01#show ip ospf int | inc Cost
  Process ID 100, Router ID 64.100.34.2, Network Type POINT_TO_POINT, Cost: 1562
  Topology-MTID    Cost    Disabled    Shutdown      Topology Name


Billy