ATM interface keeps "flapping"

[IllegalOperation]

Hello once again all. I have noticed that at specific times (around 5:00pm EST mostly), my WAN interface randomly drops. More specifically - the "ATM interface".

The router is a Cisco 827. When I do a debug PPP and ATM errors, I get these error messages...

*Mar 1 00:01:41.735: DSL: Defect: LOS LOF LCDf LOM: retraining
*Mar 1 00:01:44.723: %LINK-3-UPDOWN: Interface ATM0, changed state to down
*Mar 1 00:01:45.723: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0, chan
ged state to down
*Mar 1 00:01:53.063: Vi1 LCP: echo_cnt 2, sent id 3, line up
*Mar 1 00:02:03.227: %LINK-3-UPDOWN: Interface ATM0, changed state to up
*Mar 1 00:02:04.227: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0, chan
ged state to up


So far I have only been successful stopping this problem by constantly rebooting the router. I dont know if this problem is related to the time of day or not. Also, I noticed that the router only has 368308 bytes of free memory (its the way I have it set up).

Anyways, here is the running config. Let me know if you see any reasons why my interface would be dropping. Thanks....


Current configuration : 2627 bytes
!
version 12.2
no parser cache
no service single-slot-reload-enable
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Odyssey1
!
logging rate-limit console 10 except errors
enable secret *******
enable password *******
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
ip subnet-zero
ip name-server *.*.*.*
ip name-server *.*.*.*
!
no ip dhcp-client network-discovery
vpdn enable
!
vpdn-group pppoe
request-dialin
protocol pppoe
!
bridge irb
!
!
!
interface Tunnel0
ip address *.*.*.* 255.255.255.252
tunnel source Dialer1
tunnel destination *.*.*.*
!
interface Ethernet0
ip address *.*.*.* 255.255.255.0
no ip redirects
ip nat inside
ip tcp adjust-mss 1452
no ip mroute-cache
no cdp enable
!
interface ATM0
no ip address
no ip redirects
no ip mroute-cache
no atm ilmi-keepalive
bundle-enable
dsl operating-mode auto
bridge-group 1
bridge-group 1 spanning-disabled
!
interface ATM0.1 point-to-point
no ip mroute-cache
pvc 0/35
pppoe-client dial-pool-number 1
!
!
interface Dialer1
mtu 1492
ip address *.*.*.* 255.255.255.248
ip nat outside
encapsulation ppp
dialer pool 1
no cdp enable
ip access-group odyssey in
ppp pap sent-username ************.net
password *******
!
ip classless
ip route 0.0.0.0 0.0.0.0 *.*.*.*
ip route ***** 255.255.255.0 Tunnel0
ip route ***** 255.255.255.0 Tunnel0
ip http server
!
!
ip access-list extended odyssey
permit tcp any any established
deny tcp any any eq 135
deny tcp any any eq 137
deny tcp any any eq 138
deny tcp any any eq 139
deny tcp any any eq 445
deny tcp any any eq 593
deny tcp any any eq 1433
deny tcp any any eq 4444
deny udp any any eq netbios-ns
deny udp any any eq netbios-dgm
deny udp any any eq tftp
deny udp any any eq 135
deny udp any any eq netbios-ss
deny udp any any eq 445
deny udp any any eq 1434
permit ip any host *****
permit ip host ***** any
permit ip host ***** any
permit ip ***** 0.0.0.255 any
permit ip ***** 0.0.0.255 any
permit ip host ***** any
permit ip host ***** any
permit ip ***** 0.0.0.255 any
permit ip host ***** any
permit ip host ***** any
ip nat inside source list 1 interface Dialer1 overload
ip nat inside source static *.*.*.* 67.37.22.133
access-list 1 permit *.*.*.* 0.0.0.255
no cdp run
!
line con 0
stopbits 1
line vty 0 4
password *******
login
!
scheduler max-task-time 5000
end

 

[IllegalOperation]

Bump. I still havent figured this one out. Anyone ever have problems on the WAN interface like this with a DSL router before?

When I do a debug ATM errors, I get this initial message when the interface goes down...

"Oct 7 00:01:41.735: DSL: Defect: LOS LOF LCDf LOM: retraining"


I appreciate any assistance....

 

[jimmyzz]

IllegalOperation,
The fact that your router can make a connection and the link stays up for while would indicate that your router config is okay, and the problem is most likely with ADSL link. When your router loses its connection it will try to "retrain" the line. However sometimes it can not clear the old connection. Next time this happens, unplug the adsl cable for a few secs. When you reconnect the cable, the router should retrain itself ok. This will save you having to reboot the router. I would speak to your line provider to determine if they can troubleshoot the line problem.

JimmyZ

 

[IllegalOperation]

Thanks Jimmy.

I was actually using a different DSL router, for a little bit over a year without any problems. This problem started happening like a month or so after I got this 827, which is refurbished.

My question is if my provider tests out the line and no problems are found - what other possibilities are there that would cause this problem? Could it also be a "hardware" problem with the router? Bad interface? Is there another debug feature that I can use to further troubleshoot this problem?

 

[jimmyzz]

IllegalOperation,
"debug atm errors" and "debug atm events" are the commands I use. Though I've only ever had to use them when having problems with the initiating the line connection. I haven't experienced the line flapping like yourself. When using the debug atm events, if the modem state remains in 0x8 this indicates a problem with the "line training". The modem state 0x10 indicates a successful line "train". You wouldn't leave your debugging on when the router is in production so it would be difficult to monitor when the line goes down, hence this is why I only ever use it to test the initial line connection.

The error message "Defect: LOS LOF LCDf LOM: retraining" could indicate a "noisy line" or bad cable. I could only suggest swapping out the cable first, then the interface and router (if you have a spare one) to eliminate all local devices so you can go back to your line provider.

JimmyZ