Comtech EF Data SLM-5650A Installation And Operation Manual page 500

H.2.5.3 OSPFv2 Summary
The proposed solution using router-configurable IP tunneling to connect the remotes to the hub
OSPF router satisfies the use case with minimal operator configuration.
While the addition of an IP tunnel will add overhead, the overall reduction in satellite bandwidth
using the dynamic shared bandwidth functionality of Vipersat will more than offset the added
overhead. Load switching, used in conjunction with OSPF, will allow the bandwidth to be
automatically returned to the pool once a lower-cost terrestrial link is connected.
Advantages
•
Allows for automatic path selection via OSPF in a split path configuration with minimal
impact to the network.
•
Because each ship is its own area, there will be a reduced amount of OSPF traffic over
the satellite.
•
If the operator uses Vipersat load switching at the remote (i.e. shipboard SLM-5650A
NP), then once the terrestrial link is connected, traffic will be redirected to fiber link and
the load-switching algorithm will free the satellite link and return it to STDMA operation.
This will free up significant satellite bandwidth automatically for use by other ships still at
sea.
•
Satellite link availability will still be available to the participating OSPF routers because
periodic LSA and Hello packets will not be received on the router interface in case of
satellite outage.
•
Reduces the number of OSPF nodes in the network.
•
Allows for automatic path selection via OSPF in a split path configuration with minimal
impact to the network.
Disadvantages
•
Because IP tunnels are set up from the remote ASBR to the hub backbone router, an
additional 20-byte IP header will be added to all packets traversing the satellite interface.
•
An IP tunnel will have to be configured for each ship to the hub OSPF router.
Appendix I H–8
SLM-5650A Satellite Modem
Revision 10
MN-SLM-5650A