Bandwidth and EIGRP settings

e24ohm

Folks:
I am trying to understand when I would set the bandwidth on my T1 link artificially low, and increase the percentage of bandwidth EIGRP would/will use. Can anyone give a real world example?

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Interface serial 1
bandwidth 40
ip bandwidth-percent eigrp 1 200
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As you see from my example, I am setting the bandwidth for eigrp to use 80 kbps. Is this going to be enough for a T1 link?

Thank you
J

kryolla

I think by default this is set to 50% of the link bandwidth. It was set to this so that eigrp traffic doesn't take over the link. If you were to play with the setting you can either loose your neighbor if you were to lower it or have eigrp take over the link if you were to raise it. Taken into account the clock rate of the interface. For a T1 I would leave it as the default and for some reason if i start having a bouncing neighbor or routes getting removed then istalled, I would investigate why am I having so much eigrp traffic and if it is legit then bump it up i..e having 100k eigrp routes or start thinking of a way to decrease the size of the routing table. You will more than likely play with this on slow bandwidth links and frame relay links. My 2 cents

e24ohm

kryolla wrote: »

I think by default this is set to 50% of the link bandwidth. It was set to this so that eigrp traffic doesn't take over the link. If you were to play with the setting you can either loose your neighbor if you were to lower it or have eigrp take over the link if you were to raise it. Taken into account the clock rate of the interface. For a T1 I would leave it as the default and for some reason if i start having a bouncing neighbor or routes getting removed then istalled, I would investigate why am I having so much eigrp traffic and if it is legit then bump it up i..e having 100k eigrp routes or start thinking of a way to decrease the size of the routing table. You will more than likely play with this on slow bandwidth links and frame relay links. My 2 cents

I appreciate your help...thanks.

Bosefus

If you set the bandwidth lower than the physical link, will the link become under utilized?

For instance setting a T1 to 768 with the bandwidth command, will 1.544 worth of data still be able to be send down the link?

If for all purposes the router things the link is 768 because of the command, I dont see how it could send 1.544 but I have been told that it still would.

If I understand it correctly, the load rating of the show interface output would also take into account the bandwidth command.

networker050184

Bosefus wrote: »

If you set the bandwidth lower than the physical link, will the link become under utilized?

For instance setting a T1 to 768 with the bandwidth command, will 1.544 worth of data still be able to be send down the link?

If for all purposes the router things the link is 768 because of the command, I dont see how it could send 1.544 but I have been told that it still would.

If I understand it correctly, the load rating of the show interface output would also take into account the bandwidth command.

The bandwidth command does not affect the traffic rate sent out of the interface. It is only used as a reference by the router for calculations by routing protocols and QoS processes.

Bosefus

Thank you for clearing that up for me.