Always an issue when it is come to calculation :) I watched VOD for EIGRP
unequal cost load balacing and try to calculate FD by following formula
Rack1R5#show ip eigrp topology 4.0.0.0
IP-EIGRP (AS 100): Topology entry for 4.0.0.0/8
State is Passive, Query origin flag is 1, 2 Successor(s), FD is 2297856
Routing Descriptor Blocks:
155.1.0.4 (Serial1/0.1), from 155.1.0.4, Send flag is 0x0
Composite metric is (2297856/128256), Route is Internal
Vector metric:
Minimum bandwidth is 1544 Kbit
Total delay is 25000 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1
To know how metric calculated on above output , I used following formula:
a) 2.56 x 10^12 / BW (in bps) = 2.56 x 1000000000000 / 1544000 =
1658031.0880829015544041450777202 = 1658031
b) Delay : 2500 x 256 = 640000
Metric = a + b = 1658031 + 640000 = *2298031*
Now as per output , The metric for 4.0.0.0 is 2297856 and if I subtract
both metric it will come up 175 , not sure why it is not match exactly.
The 4.0.0.0 prefix is advertise by router 4 :
Rack1R4# sh ip eigrp topology 4.0.0.0
IP-EIGRP (AS 100): Topology entry for 4.0.0.0/8
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 128256
Routing Descriptor Blocks:
0.0.0.0 (Loopback4), from Connected, Send flag is 0x0
Composite metric is (128256/0), Route is Internal
Vector metric:
Minimum bandwidth is 10000000 Kbit
Total delay is 5000 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1514
Hop count is 0
Rack1R4#
Please guys help
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