To whom it may concern:
Our main problem is a connectivity issue, that follows them following pattern:
We have a DSLAM connected via an ATM cloud to our BRAS named iadsl-tlx-staana-2, the assigned IP address to the DSLAM is 201.122.81.209; this one has to be reached via the following PVC:
iadsl-tlx-staana-2#sh run int ATM 6/0/1.1
Building configuration...
Current configuration : 483 bytes
!
interface ATM6/0/1.1 multipoint
description GESTION DSLAM
mtu 9180
ip address 201.122.81.222 255.255.255.240
ip access-group dslams out
ip verify unicast reverse-path
no ip mroute-cache
atm pppatm passive
pvc 2/32
protocol ip 201.122.81.209 broadcast
ubr 128
encapsulation aal5snap
Our customers had been complaining about connectivity issues, while troubleshoot it we noticed that we did not have connectivity at all:
iadsl-tlx-staana-2#ping 201.122.81.209
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 201.122.81.209, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
iadsl-tlx-staana-2#
So in order to obtaing more information we enabled the following debug the which showed the output docummented as follows:
iadsl-tlx-staana-2#debug atm packet interface atm6/0/1.1
ATM packets debugging is on
Displaying packets on interface ATM6/0/1.1
iadsl-tlx-staana-2#show debug
Generic ATM:
ATM packets debugging is on
Oct 10 13:32:00: ATM6/0/1.1(O):
VCD:0x1 VPI:0x2 VCI:0x20 DM:0x100 SAP:AAAA CTL:03 OUI:000000 TYPE:0800 Length:0x70
Oct 10 13:32:00: 4500 0064 109B 0000 FF01 7459 C97A 51DE C97A 51D1 0800 7504 0049 0002 0000
Oct 10 13:32:00: 0001 7FCD 892C ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD
Oct 10 13:32:00: ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD
Oct 10 13:32:00: ABCD ABCD ABCD ABCD ABCD
Oct 10 13:32:00:
Oct 10 13:32:01: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:02: ATM6/0/1.1(O):
VCD:0x1 VPI:0x2 VCI:0x20 DM:0x100 SAP:AAAA CTL:03 OUI:000000 TYPE:0800 Length:0x70
Oct 10 13:32:02: 4500 0064 109C 0000 FF01 7458 C97A 51DE C97A 51D1 0800 6D23 0049 0003 0000
Oct 10 13:32:02: 0001 7FCD 910C ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD
Oct 10 13:32:02: ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD
Oct 10 13:32:02: ABCD ABCD ABCD ABCD ABCD
Oct 10 13:32:02:
Oct 10 13:32:03: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:04: ATM6/0/1.1(O):
VCD:0x1 VPI:0x2 VCI:0x20 DM:0x100 SAP:AAAA CTL:03 OUI:000000 TYPE:0800 Length:0x70
Oct 10 13:32:04: 4500 0064 109D 0000 FF01 7457 C97A 51DE C97A 51D1 0800 6552 0049 0004 0000
Oct 10 13:32:04: 0001 7FCD 98DC ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD
Oct 10 13:32:04: ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD
Oct 10 13:32:04: ABCD ABCD ABCD ABCD ABCD
Oct 10 13:32:04:
Oct 10 13:32:04: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:04: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:05: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:05: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:05: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:05: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:05: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:05: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:06: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:06: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:07: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Oct 10 13:32:07: ATM Auto sensing: Not changing encap in threshold time. Dropping frame.
Verifying the PVC counters:
ATM6/0/1.1: VCD: 1, VPI: 2, VCI: 32
UBR, PeakRate: 128 (302 cps)
CDVT: 714.0 Usecs, High Watermark: 56, Low Watermark: 48
AAL5-LLC/SNAP, etype:0x0, Flags: 0x1040, VCmode: 0x0, Encapsize: 12
OAM frequency: 0 second(s), OAM retry frequency: 1 second(s)
OAM up retry count: 3, OAM down retry count: 5
OAM Loopback status: OAM Disabled
OAM VC Status: Not Managed
OAM Loop detection: Disabled
ILMI VC status: Not Managed
InARP frequency: 15 minutes(s)
High Watermark: 56, Low Watermark: 48
InPkts: 0, OutPkts: 0, InBytes: 0, OutBytes: 0
InPRoc: 0, OutPRoc: 423, Broadcasts: 0
InFast: 0, OutFast: 0
InPktDrops: 0, OutPktDrops: 0
Out CLP=1 Pkts: 0
OAM cells received: 0
F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0
OAM cells sent: 5
F5 OutEndloop: 5, F5 OutSegloop: 0, F5 OutAIS: 0, F5 OutRDI: 0
OAM cell drops: 0
Status: UP
We realized thar there were not packets comming nor incoming through the pvc mentioned.
Afterwards, PVC 2/32 was reconfigured as follows:
iadsl-tlx-staana-2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
iadsl-tlx-staana-2(config)#int ATM6/0/1.1 multipoint
iadsl-tlx-staana-2(config-subif)#no pvc 2/32
iadsl-tlx-staana-2(config-subif)#pvc 2/32
iadsl-tlx-staana-2(config-if-atm-vc)# protocol ip 201.122.81.209 broadcast
iadsl-tlx-staana-2(config-if-atm-vc)# ubr 128
iadsl-tlx-staana-2(config-if-atm-vc)# encapsulation aal5snap
In consequence connectivity has been restored:
iadsl-tlx-staana-2#ping 201.122.81.209
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 201.122.81.209, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 36/52/60 ms
To provide you more information about our BRAS let me send you the following details:
model:
Cisco C10008 (PRE4-RP)
software version:
12.2(33)SB10
LC:
4oc3atm-1
Can anyone help me to determine the root cause of this behavior?
Thanks and regards!
elporsche & Juli
