Dynamic Re-Calculation Of Link Bankwidth; Weighted Ecmp For Static Routes - Dell C9000 Series Networking Configuration Manual

Dynamic Re-calculation of Link
Bankwidth
The Link cost associated with a port channel interface (LAG) changes whenever a member is added or
deleted.
Continuous link flapping results in the re-calculation of the link costs. This behaviour also causes unnecessary
processing overhead on the device as it advertises these changed link costs to its peers and updates its RTM
when ever there is a change in the member status.
To avoid the re-calculation of Link costs for continuous link flaps, the updated link cost is re-calculated using
a timer. This timer is activated every five minutes to check if there is any change in the link cost associated
with the EBGP neighbors (directly connected).

Weighted ECMP for Static Routes

Dell Networking OS also supports Weighted ECMP for static routes.
You can configure weights corresponding to the paths for a static destination. If all configured paths have
weights, traffic distribution is performed using the Weighted ECMP method with the RTM these passing
weights to the FIB.
If all configured paths do not have weights, regular ECMP is used to determine traffic paths. Also, paths that
are configured with a weight value of 0 are explicitly excluded from Weighted ECMP calculations. The RTM
does not inform the FIB about these paths (next-hops).
NOTE: Dell Networking OS also supports a global configuration parameter to enable or disable Weighted
ECMP for static routes on the system.
The following example shows weighted ECMP configuration for Static Routes:
Dell(conf)#ip route 1.1.1.0/24 4.4.4.2 weight 100
Dell(conf)#ip route 1.1.1.0/24 6.6.6.2 weight 200
Dell#show running-config | grep route
ip route 1.1.1.0/24 4.4.4.2 weight 100
ip route 1.1.1.0/24 6.6.6.2 weight 200
Dell(conf)#ip route
Dell(conf)#ip route vrf test
Dell(conf)#
Dell(conf)#
Dell#show running-config | grep route
ip route vrf test
ip route vrf test
vrf test 1.1.1.0/24 4.4.4.2 weight 100
1.1.1.0/24 6.6.6.2 weight 200
1.1.1.0/24 4.4.4.2 weight 100
1.1.1.0/24 6.6.6.2 weight 200
Equal Cost Multi-Path (ECMP) 419