Re: Backup interface

Hi Anh,

Not sure if this help now... But I have simulated the failures easily with
assigning non-exist DLCI to P2P Interface.
Seeing your case, If you change Serial Interface Encapsulation to HDLC or
PPP, it will definitely trigger backup interface for sure.

Not sure depending on your configuration on other side router, it will
detect this failure and change its routing table.
In case, As Nicky said,
2. Second: You are using main FR interface as primary, so when the other
frame-relay side is down, the primary is also up --> Backup interface does
work as you expect. Solution are using point-to-point FR interface as
primary interface or EEK to detect the status of the other FR side.

########################### My configs are as below
#########################

Rack1R4#sh run int s0/0.1
Building configuration...

Current configuration : 162 bytes
!
interface Serial0/0.1 point-to-point
 backup delay 3 60
 backup interface Serial0/1
 ip address 155.1.0.4 255.255.255.0
 frame-relay interface-dlci 405
end

Rack1R4#sh run int s0/1
Building configuration...

Current configuration : 106 bytes
!
interface Serial0/1
 ip address 155.1.45.4 255.255.255.0
 serial restart-delay 0
 clock rate 64000
end

################ Debug Output upon using # no shut on R4 under Serial 0/0.1
Interface #######################
*Mar 1 04:10:16.030: BACKUP(Serial0/0.1): event = primary interface
shutdown
*Mar 1 04:10:16.034: BACKUP(Serial0/0.1): secondary interface (Serial0/1)
moved to standby
*Mar 1 04:10:16.034: BACKUP(Serial0/0.1): changed state to "disabled"
*Mar 1 04:10:16.990: BACKUP(Serial0/0.1): event = primary interface went
down
*Mar 1 04:10:16.990: BACKUP(Serial0/0.1): backup is currently disabled on
this interface

################ Debug Output upon using # frame-relay interface-dlci 999
under Serial 0/0.1 Interface ######################
*Mar 1 04:12:37.662: BACKUP(Serial0/0.1): event = timer expired on primary
*Mar 1 04:12:39.990: BACKUP(Serial0/0.1): event = primary interface went
down
*Mar 1 04:12:39.994: BACKUP(Serial0/0.1): changed state to "waiting to
backup"
*Mar 1 04:12:42.990: BACKUP(Serial0/0.1): event = timer expired on primary
*Mar 1 04:12:43.038: BACKUP(Serial0/0.1): secondary interface (Serial0/1)
made active
*Mar 1 04:12:43.042: BACKUP(Serial0/0.1): changed state to "backup mode"
*Mar 1 04:12:44.994: %LINK-3-UPDOWN: Interface Serial0/1, changed state to
up
*Mar 1 04:12:45.006: BACKUP(Serial0/1): event = secondary interface came up
*Mar 1 04:12:46.002: %LINEPROTO-5-UPDOWN: Line protocol on Interface
Serial0/1, changed state to up
*Mar 1 04:12:46.006: BACKUP(Serial0/1): event = secondary interface came up

################### Interface Status ################

Rack1R4#sh int s0/0.1
Serial0/0.1 is down, line protocol is down
  Hardware is M4T
  Internet address is 155.1.0.4/24
  Backup interface Serial0/1, failure delay 3 sec, secondary disable delay
60 sec
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation FRAME-RELAY
  Last clearing of "show interface" counters never

################################################################################################################

HTH

Kaushal

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Received on Sun Jul 26 2009 - 18:43:30 ART