eigrp

[carl_townshend]

Hi all, How does eigrp, ospf etc know what the bandwidth is on a link, does it use all the metrics to work it out ?

[naveen_b81]

EIGRP takes the bandwidth from the "bandwidth" command on the interface.

OSPF also calculates cost from the bandwidth command on the interface.

Thanks,

Naveen B

[carl_townshend]

thanks for that, what happens if we dont put this in ?

[a.hajhamad]

it takes the default bandwidth at the interface.

show interface command to see the default bandwidth.

I hope this is helpful! please rate if it does!

Thanks

Abd Alqader

[sourabhagarwal]

EIGRP use only bandwidth and delay to calculate metric while OSPF use only cost of the link as metric to calculate routes.

In both cases, bandwidth is what is configured with "bandwidth " comman on interface. If it is not configured, by default there will be bandwidth configured which you can see from show interface commadn which is used by OSPF and EIGRP to calculate metric.

hope it helps ... rate if it does...

[kamal-learn]

hi CARL

both EIGRP and OSPF use bandwidth to caslculate the metric, EIGRP use a composite metric where it plays with five values, bandwidth,delay,load, reliability, and MTU, it defaults to only two ,bandwidth and delay.

ospf use a metric called cost it calculates it from the bandwidth by default it uses the formula 100Mbps/bandwidth.

the bandwidth used for both protocols are the one configured under interface config mode by the command [bandwidth xx(in Kbps)].

for those interfaces that are kept without configuring the speed using bandwidth command they default to a T1 speed 1544Kbps or 1.544 Mbps

HTH

please do rate if it does clarify