ON THIS PAGE
Weighted Packet Spray
Overview
Weighted Packet Spray (WPS) is a load balancing technique that distributes traffic
unevenly across multiple links based on their configured link bandwidth values. It
operates at the route level: weighted packet spray applies only when all paths for a
given route have valid link bandwidth (LBW) attributes. If any path in that route
lacks LBW information, that route alone falls back to regular ECMP, while other
routes remain unaffected. WPS can be selectively applied through firewall filters
using the weighted-packet-spray option, allowing specific flows to
be sprayed while other flows continue to use flow‑based Weighted ECMP. Consistent
implementation across network tiers ensures compatibility and stable load
balancing.
Use Feature Explorer to confirm platform and release support for specific features.
Benefits
-
Enhances traffic distribution by allocating flows proportionally to link bandwidth.
-
Improves efficiency and resilience during link failures.
-
Reduces packet loss and congestion across the network.
-
Allows selective application through firewall filters for tailored traffic management.
-
Complements Weighted ECMP by distributing packets proportionally to link bandwidth, instead of evenly across all links.
Ensures consistent performance and bandwidth utilization when applied uniformly across tiers.
Configuration
Use the weighted-packet-spray firewall filter action to
selectively enable Packet Spray only for certain flows while the rest will use
flow based weighted ECMP. In the weighted-packet-spray load
balancing method the packets will be randomly placed on the member links
according to the weights. Hence, the behavior will be similar to the Packet
Spray load balancing technique but with the additional feature of also honoring
the weights of the links. This is especially useful when for example in a
network topology involving multiple spines and leaves, if a link is down, then
this link will receive less or no traffic compared to the links that are up.
The following is an example of a configuration where the
weighted-packet-spray action is applied to packets matching
an rdma-opcode range
set firewall family inet filter WEIGHTED_PKT_SPRAY term packet_spray from rdma-opcode 6-11 set firewall family inet filter WEIGHTED_PKT_SPRAY term packet_spray then count COUNT_PKT_SPRAY set firewall family inet filter WEIGHTED_PKT_SPRAY term packet_spray then weighted-packet-spray set firewall family inet filter WEIGHTED_PKT_SPRAY term rest then count COUNT_REST set firewall family inet filter WEIGHTED_PKT_SPRAY term rest then accept set interfaces irb unit 2012 family inet filter input WEIGHTED_PKT_SPRAY