
BGP and BGP4+ Commands
| bgp | |
| Use this command to allow or disallow the switch to compare the Multi Exit Discriminator | |
| (MED) variable when choosing among routes advertised by different peers in the same | |
| autonomous system (AS). | |
| Use the bgp | |
| of MED variables when choosing among routes advertised by different peers in the same | |
| AS. | |
| Use the no variant of this command to disable this feature to disallow the comparison of | |
| the MED variable when choosing among routes advertised by different peers in the same | |
| AS. | |
Syntax [BGP/BGP4+] | bgp | |
| no bgp | |
Default [BGP/BGP4+] | Disabled | |
Mode [BGP/BGP4+] | Router Configuration | |
Usage [BGP/BGP4+] | When the bgp | |
| grouped together and ordered according to their MED values, and the best routes of each | |
| group are compared. | |
| The main benefit of this is that the choice of best route then does not depend on the order | |
| in which the routes happened to be received, which is rather random and arbitrary. | |
| To see how this works, consider the following set of bgp table entries, all for the same | |
| route: | |
| 1: ASPATH 234, MED 120, internal, IGP metric to NEXT_HOP 40 | |
| 2: ASPATH 389, MED 190, internal, IGP metric to NEXT_HOP 35 | |
| 3: ASPATH 234, MED 245, external | |
| If bgp | |
| external route. | |
| But if BGP | |
| Group 1: 1: ASPATH 234, MED 120, internal, IGP metric to NEXT_HOP 40 | |
|
| 3: ASPATH 234, MED 245, external |
| Group 2: 2: ASPATH 389, MED 190, internal, IGP metric to NEXT_HOP 35 | |
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| Note Routes from the same AS are grouped together and ordered by MED. |
Entry 1: is chosen as the best route from Group 1, since this route has the lowest MED value. Entry 2 has to be the best route in Group 2, since this is the only route in that group. These two group winners are compared against each other, and Entry 2: is chosen as the best route because Entry 2: has the lower metric to
| Software Reference Supplement for SwitchBlade® x8112, x908, x900 and x610 Series Switches |
|
AlliedWare PlusTM Operating System - Software Version | 3.29 |