Section 8.1.10 – Westermo RedFox Series User Manual
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Westermo OS Management Guide
Version 4.17.0-0
❼ Fixed MDI/MDIX crossover mode, i.e., auto-MDI/MDIX is disabled. See
for information on port crossover mode.
In most use-cases auto-negotiation of speed-duplex and MDI/MDIX is still prefer-
able, but enabling Fastlink can improve failover performance in some redundancy
applications – we refer to this as the fastlink mode:
❼ RedFox Rail [
]: RedFox Rail routers equipped with
a bypass relay are typically used in train backbones. The four backbone
ports, two in each direction, are controlled by a relay, ensuring connectivity
between routers on the backbone when one or more routers experience
power-loss. The fastlink mode minimises disruption when the bypass relay
changes state.
❼ Layer-2 redundancy: the fastlink mode can improve failover performance for
various layer-2 redundancy mechanisms, e.g., when using static link aggre-
gation (
Note
The fastlink mode requires more precise knowledge of cabling and devices
used because all automatic detection is disabled.
E.g., on the RedFox
Rail[
] bypass relay ports, make sure to setup 100 Mbps Full-Duplex, with
MDI/MDIX mode set to either:
❼ MDIX in both directions and crossover cables between switches, or
❼ MDI in one direction, MDIX in the other, with a straight cable
The latter case does however not work when a train car is turned 180➦, but
may be useful in other setups since straight cables are more commonplace.
8.1.10
Fallback default VID
The fallback default VLAN ID is generally unnecessary to configure.
The purpose of the fallback default-VID is to control what should happen with ”un-
tagged” packets entering a port only configured ”tagged” on a set of VLANs. For
more information on VLAN features and the VLAN related terms used throughout
this section, see
Every port needs to have a ”default VID”. The default VID specifies the VLAN ID
an ”untagged” packet should be associated with as it enters that port. A port’s
default VID is determined as follows:
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