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Defining a MED Metric Directly

To directly configure a MED metric to advertise in BGP update messages, include the metric-out statement:




metric-out (metric | minimum-igp offset | igp delay-med-update
| offset);

For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.

metric is the primary metric on all routes sent to peers. It can be a value in the range from 0 through 2³² – 1.

Specify minimum-igp to set the metric to the minimum metric value calculated in the IGP to get to the BGP next hop. If a newly calculated metric is greater than the minimum metric value, the metric value remains unchanged. If a newly calculated metric is lower, the metric value is lowered to that value.

Specify igp to set the metric to the most recent metric value calculated in the IGP to get to the BGP next hop.

Beginning with JUNOS Release 9.0, you can also specify for a BGP group or peer configured with the metric-out igp statement to delay sending MED updates when the MED value increases. Include the delay-med-update statement when you configure the igp statement. The default interval to delay sending updates unless the MED is lower or another attribute associated with the route has changed is 10 minutes. Include the med-igp-update-interval minutes statement at the [edit routing-options] hierarchy level to modify the default interval. For information, see Configuring a Timer to Delay Multiple Exit Discriminator IGP Updates.

Specify a value for offset to increase or decrease the metric that is used from the metric value calculated in the IGP. The metric value is offset by the value specified. The metric calculated in the IGP (by specifying either igp or igp-minimum) is increased if the offset value is positive. The metric calculated in the IGP (by specifying either igp or igp-minimum) is decreased if the offset value is negative.

offset can be a value in the range from –2³¹ through 2³¹ – 1. Note that the adjusted metric can never go below 0 or above 2³² – 1.

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