This is by design since LAGs by default will load balance on a per flow basis.
Brocade devices can be configured for load sharing over a LAG by either of the following methods:
Hash based load sharing
- Hash Based Load Sharing
- Per Packet Load Sharing
The Brocade device shares the traffic load evenly across the ports in LAG group, while ensuringthat packets in the flow are not reordered. Individual flows are assigned a LAG index to identifythem. Beginning with version 03.8.00, an improved hash based load sharing algorithm wasintroduced with the following enhancements:
- Better Distribution
- Support for 32-port LAGs
- An increased number of fields in the packet header that can be used for load balancing
- Enhanced load sharing in configurations of ECMP with LAGs.
Traffic from each flow is then distributed across the ports in the LAG group using a hash index.Options for hash based load sharing
The following options can be used to refine the hash calculations used for LAGs:
- Speculate UDP or TCP Headers
- Mask Layer-4 Source and Destination Port Information
- Hash Diversification
Each of these options when configured apply to both IP Load Sharing and LAG Load sharing.Per packet server LAG load sharing
Per packet LAG load balancing is a type of LAG that load balances traffic on a per-packet basis, as compared to traditional server LAG load-balancing which balances traffic based on packet content such as source or destination addresses. In per packet server LAG load balancing, the packet processor (PPCR) on each module selects a port in the per packet server LAG to forward traffic in a round-robin fashion. For example, if the first port of the per packet server LAG is currently selected, the second port of the per-packet server LAG will be used next, and so on. Consequently, traffic is evenly distributed among all of the ports that are configured in a per packet server LAG. Traffic that can be forwarded out of a per-packet LAG includes Layer 2 switching traffic, Layer 3 routing traffic, L3VPN (2547) traffic, VLL and VPLS traffic.