Netgear XCM8806 Chassis User Manual - Page 598

NETGEAR 8800 User Manual Note: Although these priorities can be changed, do not attempt any manipulation unless you are expertly familiar with the possible consequences. Table 57. Relative Route Priorities Route Origin Direct BlackHole Static ICMP EBGP IBGP OSPFIntra OSPFInter RIP OSPFExtern1 OSPFExtern2 BOOTP Priority 10 50 1100 1200 1700 1900 2200 2300 2400 3200 3300 5000 IP Route Sharing and ECMP IP route sharing allows a switch to communicate with a destination through multiple equal-cost routes. In OSPF and BGP, this capability is referred to as equal cost multipath (ECMP) routing. Without IP route sharing, each IP route entry in the routing tables lists a destination subnet and the next-hop gateway that provides the best path to that subnet. Every time a packet is forwarded to a particular destination, it uses the same next-hop gateway. With IP route sharing, an additional ECMP table lists up to 2, 4, or 8 next-hop gateways (depending on the platform and feature configuration) for each route in the routing tables. When multiple next-hop gateways lead to the same destination, the switch can use any of those gateways for packet forwarding. IP route sharing provides route redundancy and can provide better throughput when routes are overloaded. The gateways in the ECMP table can be defined with static routes, or they can be learned through the OSPF or BGP protocols. For more information on the ECMP table, see ECMP Hardware Table on page 609. 598 | Chapter 20. IPv4 Unicast Routing