My company uses Cisco 891's in replacement of the 1811 where we would have DBU used via an external modem and a triggered time of 3 minutes after a primary connection failure was identified. In testing the 891 in a Layer 2 failure environment, it is within milliseconds that the v.92 port is engaging after the layer 2 failure. Has anyone been able to get it to attempt at a more than millisecond rate? Any help would be very beneficial.
Redacted config from router:
ip sla 1
icmp-echo <%= probeIP1 %> source-interface GigabitEthernet0
timeout 5000
frequency 30
ip sla schedule 1 life forever start-time now
ip sla 2
icmp-echo <%= probeIP2 %> source-interface GigabitEthernet0
timeout 5000
frequency 30
ip sla schedule 2 life forever start-time now
!
track 100 ip sla 1 reachability
delay down 180 up 180
!
track 200 ip sla 2 reachability
delay down 180 up 180
!
track 300 list threshold weight
object 100
object 200
!
interface Async1
no ip address
ip virtual-reassembly
encapsulation ppp
ip tcp adjust-mss 1062
no ip route-cache
dialer in-band
dialer pool-member 2
async mode interactive
routing dynamic
!
interface Dialer2
bandwidth 56
ip address negotiated
ip virtual-reassembly
encapsulation ppp
dialer pool 2
dialer idle-timeout 60
dialer string <%= dbudial1 %>
dialer string <%= dbudial2 %>
dialer-group 2
no cdp enable
ppp authentication chap pap callin
ppp chap hostname <%= dbulogin %>.<%= dburealm %>
ppp chap password <%= dbupassword %>
ppp pap sent-username <%= dbulogin %>.<%= dburealm %> password <%= dbupassword %>
no cdp enable
!
ip route 0.0.0.0 0.0.0.0 <%= wangateway %> track 300
ip route 0.0.0.0 0.0.0.0 Dialer2 254
!
line 1
modem InOut
stopbits 1
speed 115200
line aux 0
exec-timeout 30 0
modem InOut
stopbits 1
Debugs from when Layer 2 failure initiated:
000416: Mar 14 12:53:18.903 PST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0, changed state to down
000417: Mar 14 12:53:19.903 PST: %LINK-3-UPDOWN: Interface GigabitEthernet0, changed state to down
000418: Mar 14 12:53:41.607 PST: Di2 DDR: ip (s=186.0.0.0, d=0.128.0.40), 2 bytes, outgoing interesting (set by protocol)
000419: Mar 14 12:53:41.607 PST: As1 DDR: rotor dialout [best] least recent failure is also most recent failure
000420: Mar 14 12:53:41.607 PST: As1 DDR: rotor dialout [best] also has most recent failure
000421: Mar 14 12:53:41.607 PST: As1 DDR: rotor dialout [best]
000422: Mar 14 12:53:41.607 PST: As1 DDR: Dialing cause ip (s=186.0.0.0, d=0.128.0.40)
000423: Mar 14 12:53:41.607 PST: As1 DDR: Attempting to dial <%= dbudial1 %>
These configs are a mirror of the 1811 (minus the obvious SLA interface being an FE and not GE) and the 1811 would wait 3 minutes before dialup was engaged ... In a Layer 3 failure scenario on the 891 I can get the 3 minute wait period before it attempts to dial out.
