Conversation of Metrics

[kishorecisco]

Hi,

Actually Eigrp works on different metrics and OSPF works on different metrics and every protocol has its own metrics except BGP.

When redistribution happens one metrics is converted to another metrics. How is this conversion done. Is there any formula or any

method to calculate this metrics

Thank you

[Sandeep Choudhary]

HI Kishore,

Here is the link of u can redistribute OSPf into eigrp and vice versa :

http://www.getnetworking.net/tutorials/redistribution-into-eigrp

http://www.getnetworking.net/tutorials/redistribution-into-ospf

Here is the metich calculation idea:

default-metric

To set metrics for IGRP or Enhanced IGRP (EIGRP), use the default-metric command in router configuration mode. To remove the metric value and restore the default state, use the no form of this command.

default-metric bandwidth delay reliability loading mtu

no default-metric bandwidth delay reliability loading mtu

Syntax Description

bandwidth	Minimum bandwidth of the route (in kbps). It can be 0 or any positive integer.
delay	Route delay (in tens of microseconds). It can be 0 or any positive number that is a multiple of 39.1 nanoseconds.
reliability	Likelihood of successful packet transmission expressed as a number from 0 to 255. The value 255 means 100 percent reliability; 0 means no reliability.
loading	Effective bandwidth of the route expressed as a number from 0 to 255 (255 is 100 percent loading).
mtu	Maximum transmission unit (MTU) size of the route in bytes. It can be 0 or any positive integer.

Regards

Please rate if it helps.

[kishorecisco]

Thank you for the reply sir,

But my query is how one metric is converted to another metric. That is how is cost converted into bandwidth and delay in eigrp. and how eigrp metric bandwidth and delay in converted to cost.

[mohAmed khAdr]

When redis bet routing protocols << RIP, EIGRP, OSPF,BGP>> the best way to control how these metrics are converted is by using route-maps.

For OSPF the only metric that matter is cost. For EIGRP it's delay. For BGP there are a whole host of attributes << not metrics>> that depends on how you want to route<> redis routes. Also, if you have summerization, it will as well affect these routes.

HTH

THx.

[kishorecisco]

But my query is how one metric is converted to another metric. That is how is cost converted into bandwidth and delay in eigrp. and how eigrp metric bandwidth and delay in converted to cost.

[cadet alain]

Hi,

there is no conversion, you just define which metric the redistributed prefix will have when redistributed into the other protocol and of course this seed metric is a metric understandable by this protocol.

Regards.

Alain

Don't forget to rate helpful posts.

[Edwin Summers]

As Cadet Alain noted, the metric is not automatically converted. Since each protocol uses different metrics for which there is often no direct relation, the administrator must provide the routing process an initial metric. This is known as the "seed metric" and becomes the metric for routes from the point of redistribution.

Some protocols, like RIP and EIGRP, require explicit definition of a seed metric. If not defined, they default to an infinite metric and will not redistribute routes. (some exceptions, like static and connected)

Good luck!


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