This section explains how you can configure URPF loose mode on the router for both IPv4 and IPv6 networks.
Before You Begin
Before you can configure URPF loose mode on a router, you must disable the default scale on the line card, as described in
this section.
Note
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IPv6 uRPF configuration requires the hw-module fib ipv6 scale internet-optimized-disable command for all types of cards, both TCAM cards and non-TCAM cards. By default, IPv6 uses internal memory for prefixes. Therefore,
you need to configure the hw-module fib ipv6 scale internet-optimized-disable command and then reload the line card.
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Note
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The hw-module fib ipv4 scale internet-optimized command and hw-module fib ipv6 scale internet-optimized command are deprecated from Cisco IOS XR Software
Release 7.3.1 and Release 7.4.1, respectively. Hence, if you are upgrading a router (where these configurations are already existing) to Release 7.3.1 or Release 7.4.1 or later, you might see a corresponding warning message stating so.
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Note
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Line cards must be reloaded after disabling the default scale. This is done to ensure that the hw-module command configuration takes immediate effect.
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Note
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On NCS55Ax systems with external TCAM (eTCAM), the dual capacity mode need not be disabled to enable uRPF.
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For all types of line cards with TCAM:
RP/0/RP0/CPU0:router(config)# hw-module tcam fib ipv4 scaledisable
RP/0/RP0/CPU0:router(config)# hw-module fib ipv6 scale internet-optimized-disable
RP/0/RP0/CPU0:router(config)# commit
RP/0/RP0/CPU0:router(config)# end
RP/0/RP0/CPU0:router# reload location all
Proceed with reload? [confirm]
For all types of line cards without TCAM:
RP/0/RP0/CPU0:router(config)# hw-module fib ipv4 scale host-optimized-disable
RP/0/RP0/CPU0:router(config)# hw-module fib ipv6 scale internet-optimized-disable
RP/0/RP0/CPU0:router(config)# commit
RP/0/RP0/CPU0:router(config)# end
RP/0/RP0/CPU0:router# reload location all
Proceed with reload? [confirm]
Configuration
Use the following configuration to configure URPF loose mode on the router.
Note
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You must configure both IPv4 and IPv6 commands (as described in this section) for URPF to work.
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RP/0/RP0/CPU0:router(config)# interface Bundle-Ether1
RP/0/RP0/CPU0:router(config-if)# ipv4 address 10.0.0.1 255.255.255.0
RP/0/RP0/CPU0:router(config-if)# ipv4 verify unicast source reachable-via any
RP/0/RP0/CPU0:router(config-if)# ipv6 address 2001::1/64
RP/0/RP0/CPU0:router(config-if)# ipv6 verify unicast source reachable-via any
RP/0/RP0/CPU0:router(config-if)# commit
Running Configuration
Confirm your configuration as shown:
RP/0/RP0/CPU0:router(config-if)# show running-config
Thu Jul 27 14:40:38.167 IST
...
!
interface Bundle-Ether1
ipv4 address 10.0.0.1 255.255.255.0
ipv4 verify unicast source reachable-via any
ipv6 address 2001::1/64
ipv6 verify unicast source reachable-via any
!
You have successfully configured URPF loose mode on the router.