SmartNA-X
™
1G/10G User Guide 1.4
©
2015 Network Critical Solutions Limited
Chapter
7
Load Balancing
Load balancing
Load balancing allows a stream of traffic to be divided approximately evenly among multiple egress ports. The traffic
stream may come from a single ingress port or it may aggregate traffic from multiple ingress ports. Filtering may be
applied to remove unwanted traffic before the remainder is load balanced.
Note:
Load balancing becomes available on SmartNA-X devices when an
Aggregation & Filtering & Load
Balancing Feature Pack
has been installed. Please contact your SmartNA-X reseller if you wish to install this
feature.
Load balancing on SmartNA-X
Traffic is divided among the load balancing ports by examining one or more headers in each packet from the stream. The
headers to be examined are user-configurable, with nine choices available initially.
The list of headers that may be used for load balancing is as follows:
• VLAN number
• MAC source address
• MAC destination address
• IPv4 source address
• IPv4 destination address
• IPv6 source address
• IPv6 destination address
• TCP/UDP source port
• TCP/UDP destination port
Egress ports for load balanced groups may still be used as destinations for the normal mapping and filtering functions. For
example, if tools are monitoring a protocol that has separate control and data channels, it is possible to load balance the
data channel traffic across a set of tool ports, but still to replicate all control channel data to all of those tool ports at the
same time.
Load-balancing scalability
SmartNA-X supports up to eight independent load balancing groups. The packet headers used to balance each group may
be different, but there is a limit of three headers per group.
There is no fixed limit on how many ingress ports may be aggregated to feed into a group, and there is no fixed limit on
how many egress ports a group’s traffic may be shared among. However, in practice the possible configurations will be
limited by system memory. Using many groups, many packet headers and many ports all at once is not possible. See
balancing – Best practices and limitations
on page 58 for guidelines.
Load balancing consistency
Packets with the same header values are guaranteed to go to the same egress port. For example, if IPv4 source and
destination addresses are used for balancing, all traffic from address A to address B will be sent to the same egress port.
However, there is no guarantee traffic from address B to address A will also be sent to that same egress port.