Configuring Route Health Injection; Route Health Injection Overview - Cisco 7604 Configuration Manual

Configuring Route Health Injection

for the traffic on the unit. However, because the interface is configured with an asr-group number, the
unit looks at the session information for any other interfaces with the same asr-group assigned to it. It
finds the session information in the outside interface for context A, which is in the standby state on the
unit, and forwards the return traffic to the unit where context A is active.
The traffic is forwarded though the outside interface of context A on the unit where context A is in the
standby state and returns through the outside interface of context A on the unit where context A is in the
active state. This forwarding continues as needed until the session ends.
Configuring Route Health Injection
This feature depends on Cisco IOS Release 12.2(33)SXI or later, and is only available on the Catalyst
Note
6500 switch.
Route Health Injection, or RHI, is used for injecting the connected routes, static routes, and NAT
addresses configured on the FWSM into the MSFC routing table. In multiple context mode, this feature
is especially valuable because of the lack of dynamic routing protocol support. The MSFC can then
redistribute the route to other routing tables.
This section includes information on the following topics:
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Route Health Injection Overview

For connected routes, static routes, and NAT addresses, the FWSM can inject routes into the routing table
of the switch; these routes specify the IP address of the FWSM interface as the next hop IP address for
each of these FWSM networks.
For example, when you configure NAT on the FWSM, the MSFC and other external routers do not know
that those NAT addresses are connected to the FWSM unless you configure static routes on the MSFC
to point to the FWSM interface. But by utilizing RHI, you can inject the NAT addresses to point to the
FWSM interface so the MSFC can automatically forward that traffic to the FWSM.
Because the FWSM only supports OSPF or other dynamic routing protocols in single context mode, RHI
can be used in multiple mode to inject routes to the MSFC, which can then redistribute these routes
through OSPF or other dynamic routing protocols. This allows the FWSM to redistribute FWSM routes
through OSPF or other dynamic routing protocols even when running in multiple mode, by utilizing the
MSFC routing protocols and RHI.
Because the FWSM only supports OSPF or other dynamic routing protocols in single context mode, RHI
can be used in multiple mode to inject routes to the MSFC, which can then redistribute these routes
through OSPF or other dynamic routing protocols. This allows the FWSM to redistribute FWSM routes
through OSPF or other dynamic routing protocols even when running in multiple mode, by utilizing the
MSFC routing protocols and RHI.
In a failover scenario, RHI routes are injected from only Active FWSM (applicable in both
Active/Standby and Active/Active scenario). If you have FWSM failover between two chassis in
Active/Active failover mode, both of the FWSM networks inject routes to their corresponding MSFC,
corresponding to the contexts that is in the Active state.
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM
8-32
Route Health Injection Overview, page 8-32
RHI Guidelines, page 8-33
Enabling RHI, page 8-33
Chapter 8 Configuring IP Routing and DHCP Services
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