Comtech EF Data SLM-5650A - Manual (Page 411)

SLM-5650A Satellite Modem Revision 8
Appendix E MN-SLM5650A
E–7
E.2.6 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 Disadvantages
• Allows for automatic path selection via OSPF
in a split path configuration with minimal
impact to the network.
• 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.
• 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.