PA-A3-E3 ATM interface troubles

[r-sinyuk]

Hi everybody.

I have two 7200VXR interconnected via PA-A3-E3 interfaces. E3 link sometimes be unstable with

high CRC errors level (20-50 CRCs) during short

time (1..2sec). In 99.9% of cases, ATM interface

flaps down/up, but sometimes it hangs. I used

clear ip interface ATM1/0 or shutdown/no shutdown commands as solution. Probably it is a bug, but what kind of bug ? in IOS, in hardware ? ...

Routers configuration avalable on:

http://www.univ.kiev.ua/~roman/ospf/

In this situation, the main interface ATM1/0 is in up, but subinterface ATM1/0.2 is in down state.

"show atm pvc" command produce following output:

VCD / Peak Avg/Min Burst

Interface Name VPI VCI Type Encaps SC Kbps Kbps Cells Sts

1/0.1 1 0 32 PVC SNAP VBR 2000 1000 94 UP

1/0.2 best_effort 0 100 PVC SNAP UBR 33920 INAC

1/0.2 ua-ix 0 101 PVC SNAP UBR 33920 UP

1/0.2 trasport 0 102 PVC SNAP UBR 33920 UP

1/0.2 unren 0 103 PVC SNAP VBR 4000 3000 50 UP

1/0.2 world 0 104 PVC SNAP VBR 4000 3000 50 UP

1/0.2 video 0 105 PVC SNAP VBR 15000 10000 50 UP

1/0.2 inet_control 0 106 PVC SNAP VBR 1000 512 50 UP

1/0.2 net_control 0 107 PVC SNAP VBR 1000 512 50 UP

[vmoopeung]

I have heard of a similar problem, If you specify more bandwidth than the actual interace can't take then flaping may occur. Try out with this solution disable the keepalive in the interface .

[r-sinyuk]

Which bandwidth are you talking about? The 'bandwidth' interface paramenetr or PVC bandwidth? My PA-A3-E3 configured in the following way:

!

interface ATM1/0

no ip address

service-policy output CLP_Set

ip route-cache flow

atm clock INTERNAL

no atm ilmi-keepalive

!

interface ATM1/0.1 point-to-point

bandwidth 34000

pvc 0/32

vbr-nrt 2000 1000

encapsulation aal5snap

!

ipv6 address 3FFE:240B:0:1::/64 eui-64

ipv6 rip R1 enable

end

interface ATM1/0.2 point-to-point

bandwidth 34000

ip address 193.125.78.81 255.255.255.252

ip pim sparse-mode

ip ospf message-digest-key 10 md5 7 ********

bundle Main

oam retry 5 5 10

encapsulation aal5snap

oam-bundle manage 1

pvc-bundle net_control 0/107

vbr-nrt 1000 512 50

precedence 7

no bump traffic

protect vc

pvc-bundle inet_control 0/106

vbr-nrt 1000 512 50

precedence 6

bump traffic

protect group

pvc-bundle video 0/105

vbr-nrt 15000 10000 50

precedence 5

bump explicit 7

bump traffic

protect group

pvc-bundle world 0/104

vbr-nrt 4000 3000 50

precedence 4

bump traffic

protect group

pvc-bundle unren 0/103

vbr-nrt 4000 3000 50

precedence 3

bump traffic

protect group

pvc-bundle trasport 0/102

precedence 2

bump traffic

protect group

pvc-bundle ua-ix 0/101

precedence 1

bump traffic

protect group

pvc-bundle best_effort 0/100

precedence other

bump traffic

protect group

!