Best Practices For Configuring The Nat On The Cisco Asr 1000 Series Routers - Cisco Intelligent Wireless Access Gateway Configuration Manual

Flow-Based Redirect
Configuring NAT Access Interface for Ingress Traffic
interface GigabitEthernet0/0/4
ip address 36.0.0.1 255.255.255.0
ip nat inside
negotiation auto
ipv6 address FE80::200:5EFF:FE00:5213 link-local
service-policy type control PREMS
ip subscriber l2-connected
initiator unclassified mac-address
initiator dhcp
!
Configuring NAT Network Interface for Egress Traffic
interface GigabitEthernet1/2/4
description IXIA_port_for_offload
ip address 44.0.0.1 255.255.255.0
ip nat outside
load-interval 30
negotiation auto
ipv6 address 44::1/60
!
Enabling Carrier Grade NAT
ip nat settings mode cgn
no ip nat settings support mapping outside
ip nat pool natpool 55.0.0.3 55.0.255.250 netmask 255.255.0.0
ip nat inside source list 100 pool natpool overload
Best Practices for Configuring the NAT on the Cisco ASR 1000
Series Routers
The following are the recommended best practices to configure the NAT on the Cisco ASR 1000 Series
Aggregation Services Routers:
• Restriction on the total QFP DRAM usage
• Set the maximum limit for total number of NAT translations:
OL-30226-03
At 97 percent DRAM utilization, depletion messages are displayed in the syslog as a warning message
to make the operator aware of low QFP DRAM availability. We recommend that you configure QFP
DRAM CAC in the system to avoid any unexpected behavior. The Call Admission Control (CAC)
functionality ensures that new subscriber sessions cannot be established when QFP DRAM utilization
exceeds the configured threshold.
The configuration example below demonstrates configuration of a QFP DRAM threshold set to 95
percent:
platform subscriber cac mem qfp 95.
◦ ESP40: ip nat translation max-entries 1000000
◦ ESP100: ip nat translation max-entries 4000000

Best Practices for Configuring the NAT on the Cisco ASR 1000 Series Routers

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