Routing sources

Last Updated : Nov 06, 2012 |
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The Branch Gateway router supports both static and dynamic routing per interface. You can configure static routes with two levels of priority, high and low, and you can enable and configure Open Shortest Path First (OSPF) and Routing Information Protocol (RIP) dynamic routing protocols. Additionally, when DHCP client is configured on an interface, you can configure DHCP client to request a default router address from the DHCP server (DHCP option 3).
The actual source from which the router learns the next hop for any given interface is determined as follows: The router seeks the best match to a packet’s destination IP address from all enabled routing sources. If there is no best match, the next hop source is determined according to the following priority order:
  1. High priority static route (highest)
    If a high priority static route is configured on the interface, this route overrides all other sources.
  2. OSPF
    If no high priority static route is configured on the interface, but OSPF is enabled, then OSPF determines the next hop.
  3. RIP
    If no high priority static router is configured on a given interface, and OSPF is not enabled, but RIP is enabled, RIP determines the next hop.
  4. EXT OSPF
  5. DHCP
    If no high priority static router is configured on a given interface, and neither OSPF nor RIP are enabled, and DHCP client is configured on the interface with a default router requested from the DHCP server (DHCP option 3), then the default router provided by DHCP is used.
  6. Low priority static route (lowest)
When more than one next hop is learned from the same source, the router uses an equal cost multi path algorithm that performs load balancing between routes.
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