Multi-Exit Discriminator (Med) Attribute (Type 4); Med Configuration - Example 1; Figure 15: Bgp Med Configuration Example - Avaya 8000 Technical Configuration Manual

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14.5 Multi-Exit Discriminator (MED) Attribute (Type 4)

The MED attribute is an optional non-transitive attribute that hints at preferred paths for routes that come
from neighbors.
MEDs are only used with multiple connections to a neighboring AS in order to select a path for return
traffic. A lower MED value indicates a stronger MED than a higher value.
One AS sets the MED value and a different AS uses that value to select a path. When an UPDATE
message enters an AS with a MED value, the value is used to help the AS make routing decisions.
MED can also be used to load balance inbound traffic. For example, different MED values can be used
for control different CIDR blocks.

Figure 15: BGP MED Configuration Example

14.5.1 MED Configuration – Example 1
For this example, we will set the default MED setting on 8008 with a value of 10 and 9001 with a value of
100. The overall effect will result in 8008 advertising all routes with a MED setting of 10 whereas 9001 will
advertise all routes with a MED setting of 100. This should result in all traffic destined for AS 20 to
transverse over 10.1.1.12 network via 8008.
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January 2016