Netgear XCM8810 Chassis User Manual - Page 623

Any inbound RIP control packets from secondary interfaces are dropped.

Page 623 highlights

NETGEAR 8800 User Manual OSPF This section describes the behavior of OSPF in an IPv4 multinetting environment: • Each network is treated as an interface, and hello messages are not sent out or received over the non-primary interface. In this way, the router LSA includes information to advertise that the primary network is a transit network and the secondary networks are stub networks, thereby preventing any traffic from being routed from a source in the secondary network. • Any inbound OSPF control packets from secondary interfaces are dropped. • Direct routes corresponding to secondary interfaces can be exported into the OSPF domain (by enabling export of direct routes), if OSPF is not enabled on the container VLAN. • When you create an OSPF area address range for aggregation, you must consider the secondary subnet addresses for any conflicts. That is, any secondary interface with the exact subnet address as the range cannot be in another area. • The automatic selection algorithm for the OSPF router ID considers the secondary interface addresses also. The numerically highest interface address is selected as the OSPF router-id. RIP This section describes the behavior of the Routing Information Protocol (RIP) in an IP multinetting environment: • RIP does not send any routing information update on the secondary interfaces. However, RIP does advertise networks corresponding to secondary interfaces in its routing information packet to the primary interface. • Any inbound RIP control packets from secondary interfaces are dropped. • Direct routes corresponding to secondary interfaces can be exported into the RIP domain (by enabling export of direct routes), if RIP is not enabled on the container VLAN. BGP There are no behavioral changes in the Border Gateway Protocol (BGP) in an IP multinetting environment. This section describes a set of recommendations for using BGP with IP multinetting: • Be careful of creating a BGP neighbor session with a BGP speaker residing in secondary subnet. This situation can lead to routing loops. • All secondary subnets are like stub networks, so you must configure BGP in such a way that the BGP next hop becomes reachable using the primary subnet of a VLAN. • When setting the BGP next hop using an inbound or outbound policy, ensure that the next hop is reachable from the primary interface. • A BGP static network's reachability can also be resolved from the secondary subnet. • Secondary interface addresses can be used as the source interface for a BGP neighbor. Chapter 20. IPv4 Unicast Routing | 623

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Chapter 20.
IPv4 Unicast Routing
|
623
NETGEAR 8800 User Manual
OSPF
This section describes the behavior of OSPF in an IPv4 multinetting environment:
Each network is treated as an interface, and hello messages are not sent out or received
over the non-primary interface. In this way, the router LSA includes information to
advertise that the primary network is a transit network and the secondary networks are
stub networks, thereby preventing any traffic from being routed from a source in the
secondary network.
Any inbound OSPF control packets from secondary interfaces are dropped.
Direct routes corresponding to secondary interfaces can be exported into the OSPF
domain (by enabling export of direct routes), if OSPF is not enabled on the container
VLAN.
When you create an OSPF area address range for aggregation, you must consider the
secondary subnet addresses for any conflicts. That is, any secondary interface with the
exact subnet address as the range cannot be in another area.
The automatic selection algorithm for the OSPF router ID considers the secondary
interface addresses also. The numerically highest interface address is selected as the
OSPF router-id.
RIP
This section describes the behavior of the Routing Information Protocol (RIP) in an IP
multinetting environment:
RIP does not send any routing information update on the secondary interfaces. However,
RIP does advertise networks corresponding to secondary interfaces in its routing
information packet to the primary interface.
Any inbound RIP control packets from secondary interfaces are dropped.
Direct routes corresponding to secondary interfaces can be exported into the RIP domain
(by enabling export of direct routes), if RIP is not enabled on the container VLAN.
BGP
There are no behavioral changes in the Border Gateway Protocol (BGP) in an IP multinetting
environment. This section describes a set of recommendations for using BGP with IP
multinetting:
Be careful of creating a BGP neighbor session with a BGP speaker residing in secondary
subnet. This situation can lead to routing loops.
All secondary subnets are like stub networks, so you must configure BGP in such a way
that the BGP next hop becomes reachable using the primary subnet of a VLAN.
When setting the BGP next hop using an inbound or outbound policy, ensure that the next
hop is reachable from the primary interface.
A BGP static network's reachability can also be resolved from the secondary subnet.
Secondary interface addresses can be used as the source interface for a BGP neighbor.