Hi everyone!
I have wrote a couple of times about this issue I'm facing with and decided to post it once more with my configuration and all results.
I have simple scheme primary WAN goes to a switch, link is established from switch to 1841 router and router have HWIC-3G-GSM module.
(WAN=>SIWTCH=>ROUTER(With 3G)). All I need to is to Backup my primary WAN interface Fastethernet 0/0 on a router with 3G when it is down and turn it back on, when it is back online.
I'm tracking primary WAN interface for reachability of host that is situated in my primary WAN network using IP SLA. When it is down IP SLA responce with a ping timeout message and sends it to track 1. Track one changes it's state to down and changes administrative distance for primary route to 254.
All seems to be ok, untill WAN interface is back online. The point is that IP SLA can't ping through FastEthernet 0/0 while Cellular interface is used by users, IP SLA just sends to track 1 ping timeout message. Cellular interface have dialer idle-timeout timer, which is expired only when no traffic is sent to a Cellular interface. When this timer is expired, cellular interface line protocol goes down and IP SLA succesfully can ping WAN host.
Therefore, I have a situation, when I can't move from my Backup link to primary link, even if primary link is back online.
Here is my configuration. Some output have been changed for security reasons.
Current configuration : 1996 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname ROUTER
!
boot-start-marker
boot-end-marker
!
logging buffered 51200 warnings
!
no aaa new-model
!
!
dot11 syslog
ip cef
!
!
!
!
ip domain name yourdomain.com
!
multilink bundle-name authenticated
chat-script gsm "" "ATDT*98*1#" TIMEOUT 30 "CONNECT"
!
!
!
!
archive
log config
hidekeys
!
!
!
track 1 rtr 2 reachability
delay down 1 up 1
!
!
!
interface FastEthernet0/0 // WAN interface
ip address dhcp
ip nat outside
ip virtual-reassembly
duplex auto
speed auto
!
interface FastEthernet0/1 // LAN interface
ip address 192.168.0.1 255.255.255.0
ip nat inside
ip virtual-reassembly
duplex auto
speed auto
!
interface Cellular0/0/0 //Backup 3G interface
ip address negotiated
ip nat outside
ip virtual-reassembly
encapsulation ppp
dialer in-band
dialer idle-timeout 30 // Timer expires when no traffic is passing through cellular interface within 30 seconds
dialer string gsm
dialer-group 1
async mode interactive
ppp authentication chap optional
ppp chap hostname name
ppp chap password 0 LINE
!
interface Dialer1
no ip address
shutdown
!
ip local policy route-map choose_wan_outgoing_int // Created policy for route-map
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 10.10.10.1 track 1 //route to default Gateway for WAN interface(with track option)
ip route 0.0.0.0 0.0.0.0 Cellular0/0/0 150 //secondary route for backup interface
!
!
ip http server
no ip http secure-server
ip nat inside source list 1 interface Cellular0/0/0 overload
ip nat inside source list 2 interface FastEthernet0/0 overload
!
ip sla 2
icmp-echo 10.10.10.47 source-interface FastEthernet0/0 //ping every 10 seconds host situated in WAN network
timeout 4000
threshold 8
frequency 10
ip sla schedule 2 life forever start-time now
access-list 1 permit any
access-list 2 permit any
access-list 102 permit icmp any host 10.10.10.47
dialer-list 1 protocol ip list 1
!
!
!
route-map choose_wan_outgoing_int permit 10 //Telling router to use only Fa 0/0 for pinging host in WAN network
match ip address 102
set interface FastEthernet0/0
!
!
!
!
control-plane
!
!
!
line con 0
line aux 0
line 0/0/0
script dialer gsm
modem InOut
!
!
!
!
control-plane
!
!
!
line con 0
line aux 0
line 0/0/0
script dialer gsm
modem InOut
no exec
transport input all
rxspeed 3600000
txspeed 384000
line vty 0 4
login
!
scheduler allocate 20000 1000
end
Please help. I'm despaired to get this to work.
Thank you and Regards,
Aleksei
