Westermo RedFox Series User Manual
Page 364
Westermo OS Management Guide
Version 4.17.0-0
source and destination MAC address of the packet
(done in hardware).
❼ The distribution of traffic flows:. If there are many flows (and if they are of
equal load) the ability to load balance improves. This depends on the traffic
patterns in your network. Avoiding patterns where all traffic end up with the
same source and destination MAC over the aggregate improves the ability
to load balance
❼ The mapping of traffic flows to different member links: WeOS units map
traffic flows to different (active) member links in a static way. This mapping
aims to equalise the number of flows mapped to each member link, but its
effectiveness is limited when the number of flows are low.
Note
To summarise, link aggregation should generally be used as a means to
achieve redundancy in bus topologies. It may be used to increase data
capacity, however, the ability to load balance between the member links is
limited and depends on the use case.
When an aggregate is configured in WeOS, the following restrictions apply:
❼ Ethernet as member ports: Only aggregation of Ethernet ports is supported.
❼ Member ports explicitly associated with aggregate: For a port to be part of
an aggregate, it must explicitly be associated with that aggregate.
❼ Maximum 8 aggregates: At most 8 aggregates can be configured on a WeOS
unit.
❼ Maximum 8 member ports per aggregate: Each aggregate can have at most
8 member ports.
❼ Member ports in same slot: In slot based WeOS products (see
all member ports must reside in the same slot as of WeOS v4.17.0. Similar
restrictions apply to WeOS Viper, RedFox Rail (RFR) and RedFox Industrial
Rack (RFIR) products.
A aggregate has state Down when all its member ports have state Down, and the
aggregate is Up when at least one of its member ports has state Up.
1
The algorithm to determine flow uses a hash function applied to the packet’s source and desti-
nation MAC address.
2
Switching traffic over the link aggregate may improve load balancing as opposed to routing
(routers typically use the same source and destination MAC for all unicast traffic). Multicast flows
commonly utilise different destination MACs irrespective if the WeOS units are switching or routing,
thus has good load balancing properties.
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