Westermo RedFox Series Management Manual page 1081

(TCMS) backbone, ID 1 a Multimedia backbone, and the use for IDs 2 and 3
are not specified.
Note
All ETBNs attached to the same ETB need to be configured with the
same backbone identifier (e.g. TCMS(0)), as this identifier is not dy-
namically computed during the ETB inauguration.
ˆ Routing entries: TTDP populates the routing table in each of the ETBNs,
thereby enabling routing of traffic between different consist networks.
ˆ R-NAT entries: The WeOS TTDP support assumes the use of 1-1 NAT (re-
ferred to as Railway-NAT or R-NAT in IEC 61375-3-4[15]) to translate ECN
IP addresses when routing between ETB and ECN. The 1-1 NAT entries are
populated dynamically based on the TTDP IP subnet allocation.
ˆ TTDP MIB: IEC 61375-2-5 defines the TTDP MIB, which can be used by a
manager station within a consist to monitor TTDP status information on a
local ETBN.
WeOS provides some related support, relevant for IEC 61375-2-5 networks.
ˆ Router redundancy control: TTDP does not specify the exact mechanism to
control router redundancy for topologies where ECNs are connected to more
than one ETBN. In similar networks, VRRP
but in IEC 61375 backbone networks one cannot rely on VRRP and still be
compatible with the standard.
The WeOS support for router redundancy is therefore limited to using VRRP
signalling within the ECN network, and to let that VRRP state within the
ECN control router redundancy on the ETB too. (See synchronised VRRP in
section 31.1.5
– Unicast routing: The elected VRRP master will handle the unicast rout-
ing between the ETB and specific ECN.
– Multicast routing: If multicast forwarding is enabled in a redundant
ETBN topology, the elected VRRP master should also be the router
forwarding the multicast traffic between ETB and ECN. This is accom-
plished by using the WeOS multicast route control option for VRRP
tion 31.1.6).
© 2018 Westermo Teleindustri AB
for more information on this topic.)
Westermo OS Management Guide
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