WSF_COMM_ROUTER_PROTOCOL_OSPF¶
- router_protocol WSF_COMM_ROUTER_PROTOCOL_OSPF¶
router_protocol <name> WSF_COMM_ROUTER_PROTOCOL_OSPF ospf_area <address> remove_ospf_area <address> backbone <address> remove_backbone ospf_dr_priority <integer-value> hello_interval <random-time-reference> hold_timer <random-time-reference> end_router_protocol
Overview¶
WSF_COMM_ROUTER_PROTOCOL_OSPF provides an generic mission level routing capability similar to that provided by the OSPF protocol. This protocol supports the assignment of routers to “areas” in which detailed routing information is kept, while only carrying a summarized level of detail of potential recipient data in other areas.
This protocol works by generally sending periodic multicast messages that are received by other members of this protocol. This is used to dynamically detect new members, and detect the loss of other members. Data is distributed within areas, and also carried to others externally in this format. This messaging procedure is abstracted in its implementation.
When routing messages, if the recipient is in the local area, the message is directly routed to that member using a graph of area network state. If the recipient is known, but external to the area, this protocol always attempts to send the message to a defined “backbone” area. The backbone carries messages to any area, and all areas MUST be connected to the backbone.
Area connections are handled by defining certain comms as “border routers”. The user must specify these routers by providing multiple area definitions as part of the protocol input.
Only one backbone can exist per connected OSPF autonomous system (AS). All areas must connect to this area.
For destinations of messages external to OSPF enabled routers, one or more routers sharing a connection with the desired external interfaces must have an alternative routing protocol available to correctly handle external routing of those messages. As such, any OSPF enabled router with any non-OSPF routing protocol is specified as an ASBR (autonomous system border router) that can send messages external to the OSPF AS. Messages destined external to OSPF use the optimal external path from an ASBR to select the best ASBR for usage, and then route internally to that ASBR using standard OSPF routing strategies.
Not all network topologies are compatible with OSPF. All members in an area must be connected. Loss of border routers will cause a loss of transmission capabilities, as is expected with this protocol. In addition, although connections may exist externally to the OSPF provided definition, this protocol will NOT use those connections to “route around” any missing border routers, as is intended.
Finally, OSPF typically uses a metric based on transmission capability of multiple interfaces available for sending messages when making routing decisions. This metric is defined by the transmission rate of any given route divided by 100 Mbps, with a minimum value of 1.0. The only metric value less than a 1.0 is instantaneous transmission rates, which use a metric value of 0.0 in determining the cost.
Note
This protocol is provided in a beta state. Bugs or other issues may exist in this version.
Note
This protocol is extremely taxing on simulation performance. It is highly suggested to increase the hello_interval time to the highest acceptable value to avoid the numerous multicast messages being sent at each interval, and avoiding assigning large number of comms to any specific area.
Commands¶
- ospf_area <address>¶
Defines the area this comm/router belongs to in the OSPF AS. Multiple areas may be assigned if this member has a direct connection to another member in that area, defining this member as a “border router”.
- remove_ospf_area <address>¶
Removes an area defined for this protocol. Specifically provided for editing derived objects in input.
- backbone <address>¶
Defines the specified area as a backbone. This only has to be done on a protocol instance for this setting to be applied across an entire OSPF connected AS.
Only one backbone may be defined per connected OSPF AS. All other areas must connect to this area via border routers.
- remove_backbone¶
This command removes the backbone specification for this protocol type or instance. Used in cases where a protocol type is inherited from, but the specified backbone setting is not wanted.
- ospf_dr_priority <integer-value>¶
Sets the priority for this router becoming the “designated router” or “backup designated router” (DR, BDR) for its network within an area. These routers hold all of the detailed routing data for a specific area as common points of communication for all other routers in the same network. This value must be positive, where a lower value indicates a higher priority. This value also affects subsequent re-selection of these routers dynamically at runtime. Any router entering a network and area does not preempt any already established DR or BDR, even if it has a higher priority.
Default Maximum integer value
- hello_interval <random-time-reference>¶
Defines the amount of time between sending the OSPF heartbeat, the “hello” packet. If these are not received before the defined hold time, the router will be considered non-connected or non-functional and removed from network state data for routing purposes. In addition, this defines how soon a new member is detected, as this is also the method in which new members are detected.
A small value is added to this value to ensure these times are not exactly the same across the simulation, and ensure repeatability when this value is constant.
Default constant 10 s
- hold_timer <random-time-reference>¶
Defines the amount of time that before a member is dropped if a hello packet is not received. Note that the default value allows multiple hello packet transmission windows before actually being dropped due to hold time. Ensure that this value is greater than the hello_interval to avoid dropping all members from network state knowledge.
A small value is added to this value to ensure these times are not exactly the same across the simulation, and ensure repeatability when this value is constant.
Default constant 40 s
