Troubleshooting Flowchart; Solution - H3C S6805 Series Troubleshooting Manual

Troubleshooting flowchart

Figure 15 Troubleshooting ECMP forwarding failure
ECMP forwarding failure
Only one route to the destination
Route community attributes and
extended community attributes
Do routes carry the default-
gateway attribute?
Any non-BGP routes?
Number of BGP
ECMP routes set?
Contact the support

Solution

To resolve the issue:
1. Verify that the device has routes to the destination network:
a. Execute the display bgp l2vpn evpn route-distinguisher route-type ip-prefix command.
b. Verify that the device has routes to the destination network.
The routes must have the same RD and different next hops. If only one route exists, ECMP
forwarding cannot be performed.
2. Verify that the routes have the same community attributes and extended community attributes:
Yes
network?
No
Yes
not match?
No
Yes
No
Yes
No
No
Yes
No ECMP routes exist
Configure the same
attributes for the
routes
Delete the default-
gateway attribute
Raise the priority of
BGP routes
Use balance to set
the number of BGP
ECMP routes to a
value larger than 1
39
Yes
Problem resolved?
No
Yes
Problem resolved?
No
Yes
Problem resolved?
No
Yes
Problem resolved?
No
End