Radwin Ltd. 5XACMOD3C 用户手册
FinM Deployment Guide
Release 4.5.10
3‐2
Wayside Network
Network Guidelines
•
The backhaul network (existing or provided by the system integrator/customer) is used
to aggregate traffic to/from the TBSs and send it to the control/data centres.
•
The required network architecture must have a single core router, and L2 switches. All
data communication to/from the train will pass via this router.
•
A redundant ISU/OSU is provided to ensure higher resiliency of the solution.
•
The TBS's network is synchronized either via GPS‐based system (for above ground sce‐
narios) or via Ethernet‐based synchronization (for above or underground scenarios).
•
For GPS based synchronization, the TBS integrated GPS Synchronization Unit is used.
•
For Ethernet‐based synchronization, the TBS's network is synchronized by Ethernet
based synchronization, running over the same data backhaul network. The implementa‐
tion of the synchronization protocol is via an Indoor Synchronization Unit (ISU) or Out‐
door Synchronization Unit (OSU) that is connected to one of the network switches, and
provides the master clock to all TBSs in the network.
tion of the synchronization protocol is via an Indoor Synchronization Unit (ISU) or Out‐
door Synchronization Unit (OSU) that is connected to one of the network switches, and
provides the master clock to all TBSs in the network.
•
ISUs work using a star topology, while OSUs work using a ring topology.
•
The synchronization architecture may vary depending on the specific network topology,
so RADWIN needs to evaluate and approve the wayside network topology and assure it
will support the synchronization protocol. Typical synchronization requirements
include:
will support the synchronization protocol. Typical synchronization requirements
include:
• Layer 2 connection between all ISU/OSUs and TBSs.
• Maximum of 4 switches between ISU/OSUs and each TBS.
• Avoid high line speed utilization to prevent introduction of jitter and latency. The
• Avoid high line speed utilization to prevent introduction of jitter and latency. The
line load should be limited according to the following table:
•
Network switches should appropriately handle the system's relearning frames. These
frames are VLAN tagged (802.1Q). Switch should forward the relearning traffic and
update FIB (Forwarding Information Base).
update FIB (Forwarding Information Base).
•
IEEE802.3az must be disabled on all switches.
•
Spanning tree between train and wayside is not supported and must be disabled on
switch ports connected to the RADWIN radios (both TBSs and TMUs).
•
Static routing should be implemented between wayside core router and on‐board rout‐
ers. Implementation of dynamic routing protocols should be confirmed with RADWIN
professional services.
professional services.
Table 3‐1: ISU/OSU‐TBS switches vs. line utilization
Number of Switches
Between ISU/OSU and TBS
Maximal Line Utilization
1
95%
2
85%
3
75%
4
65%