Huawei BGP Routing Principles

BGP routing is optimal, in the absence of filtering, there are two conditions related: Next hop can be reached, synchronous shutdown. If these two conditions are not met, the routing is not optimal.

BGP Routing principle:

1. If the next hop of this route is unreachable, this route is ignored
2. Preferred-valnue value higher priority, Huawei Private attribute, only local meaningful
3. Local-preference highest-Value routing priority
4. Aggregation routes take precedence over non-aggregated routes
5. Local manual aggregation routes have higher precedence than local auto-aggregated routes
6. Routes introduced locally through the network command take precedence over routes introduced locally through the Import-route command
7. The shortest path of the as path takes precedence
8. Comparing the origin attribute, IGP is superior to EGP,EGP better than incomplete
9. Select a smaller route for Med
10. EBGP routing is better than IBGP routing
11. BGP priority selection to BGP next hop the lowest IGP metric value path
    When all of the above are the same, the equivalent route can be load-sharing (note: As_path must be consistent when load sharing, the following 3 principles are invalid)
12. Compare cluster_list length, short preferred
13. Compare originator_id (if there is no originator_id, compare with router_id) and select a path with a smaller number.
14. Compare the IP address of the peer and select the path with the smallest IP address value.

Huawei BGP Routing Principles