(Optional) Configuring a Load Balancing Mode
Context
An Eth-Trunk uses flow-based load balancing. Flow-based load balancing ensures that frames of the same data flow are forwarded on the same physical link. Different data flows are forwarded on different physical links to balance the network load.
You can configure a common load balancing mode in which IP addresses or MAC addresses of packets are used to load balance packets; you can also configure an enhanced load balancing mode for Layer 2 packets, IP packets, and MPLS packets.
Load balancing is valid only for outgoing traffic; therefore, the load balancing modes for the interfaces at both ends of the link can be different without affecting each other.
When more than 128 Eth-Trunks or 16 member interfaces are configured using the assign trunk { trunk-group group-number | trunk-member member-number }* command, only the enhanced mode can be used for load balancing. If the enhanced mode is not used, problems such as packet loss and uneven load balancing may occur.
SA series cards do not support the enhanced load balancing mode. SA series cards still use the common load balancing mode even if enhanced load balancing is configured.
Procedure
- Configure a common load balancing mode.
- Configure
an enhanced load balancing mode.
- Run the following commands as required. You can configure
load balancing modes for Layer 2 packets, IPv4 packets, IPv6 packets,
and MPLS packets respectively.
- Run:
l2 field [ dmac | l2-protocol | smac | sport | vlan ] *A load balancing mode of Layer 2 packets is set.
By default, load balancing of Layer 2 packets is based on the source MAC address (smac) and destination MAC address (dmac).
- Run:
ipv4 field [ dip | l4-dport | l4-sport | protocol | sip | sport | vlan ] *A load balancing mode of IPv4 packets is set.
By default, load balancing of IPv4 packets is based on the source IP address (sip) and destination IP address (dip).
- Run:
ipv6 field [ dip | l4-dport | l4-sport | protocol | sip | sport | vlan ] *A load balancing mode of IPv6 packets is set.
By default, load balancing of IPv6 packets is based on the source IP address (sip) and destination IP address (dip).
- Run:
mpls field [ 2nd-label | dip | dmac | sip | smac | sport | top-label | vlan ] *A load balancing mode of MPLS packets is set.
By default, load balancing of MPLS packets is based on the two outer labels (top-label and 2nd-label) of each packet.
In an S12700 CSS, the CSS links use the profile configured by the load-balance-profile command to load balance traffic. If no profile for enhanced load balancing is created, the CSS links use the default enhanced load balancing mode. If traffic is not evenly distributed on the CSS links, some links may be congested and packets may be dropped. To prevent this problem, it is recommended that you choose multiple keywords in the mpls field, l2 field, ipv4 field, and ipv6 field commands when configuring load balancing modes for various packets.
- Run:
The preceding load balancing modes apply only to known unicast traffic. To configure a load balancing mode for unknown unicast traffic, run the unknown-unicast load-balance { dmac | smac | smacxordmac | enhanced } command in the system view.When the enhanced load balancing mode is used for unknown unicast traffic, specify the VLAN ID in the load balancing profile. When the outbound interface is an Eth-Trunk and is added to a user VLAN, multicast traffic on the device equipped with all X series cards can be load balanced based on the user VLAN. If other cards are installed on the device, multicast traffic on the device cannot be load balanced based on the user VLAN.
- Run the following commands as required. You can configure
load balancing modes for Layer 2 packets, IPv4 packets, IPv6 packets,
and MPLS packets respectively.