Hi!,
we have recently adquired a new 3725 as Internet router. It has a FastEthernet interface to our network and a ATM OC-3 interface to an external provider. We are using NAT because we have not enough public IP addresses. The router is working with 8500 NAT translations and 10 Kpps that are equivalent to 6-7 Mbps. The CPU reaches 40%.
Here is the configuration:
interface Loopback1
description Interfaz de Gestion
ip address 10.0.0.10 255.255.255.255
!
interface Loopback2
ip address y1.y2.y3.1 255.255.255.0
no ip unreachables
no ip proxy-arp
!
interface FastEthernet0/0
ip address 195.57.165.174 255.255.255.248
ip nat inside
speed 100
full-duplex
!
!
interface ATM1/0
no ip address
no atm auto-configuration
no atm ilmi-keepalive
no atm address-registration
no atm ilmi-enable
!
interface ATM1/0.197 point-to-point
description CONEXION ATM 34Mbps RED NURIA de TDATA
bandwidth 8000
ip address x1.x2.x3.x4 255.255.255.252
no ip proxy-arp
ip nat outside
pvc 18/197
vbr-nrt 9360 9360 1
oam-pvc manage 5
oam retry 3 3 5
encapsulation aal5snap
!
!
ip nat translation timeout 300
ip nat translation tcp-timeout 300
ip nat translation dns-timeout 300
ip nat translation max-entries 15000
ip nat service H225 tcp port 19297
ip nat service H225 tcp port 16596
ip nat pool POOL-PUBLICO y1.y2.y3.2 y1.y2.y3.254 netmask 255.255.255.0
ip nat inside source list ACL-NAT pool POOL-PUBLICO overload
ip classless
ip route 0.0.0.0 0.0.0.0 x1.x2.x3.x5
ip route 10.0.0.0 255.0.0.0 195.57.165.169
no ip http server
ip pim bidir-enable
!
!
ip access-list extended ACL-NAT
permit ip 10.10.0.0 0.0.31.255 any
deny ip any any
!
The proccess with higher CPU utilization is IP Input:
46 23499576 53512897 439 21.28% 20.35% 20.68% 0 IP Input
We are using Fast Switching and have tested CEF, but CPU usage is lower with Fast Switching.
The question is: can we increase the performance using bridging? Is possible configure NAT and bridging with IRB? Can we reduce the CPU utilization with IRB? Is there another way to get it?
Thanks in advance.
Antonio M.
