03-08-2006 01:32 PM - edited 03-03-2019 11:59 AM
Hi,
I have a router 3725 with ATM OC-3 module. ATM interface has many PVCs. All PVCs (except the one) are switched by network operator to others sites and are terminated on the Cisco routers. Some of these PVCs are translated by network operator to Frame Relay. One PVC is used to connect to the internet and is terminated by network operator. Network operator uses Nortel for ATM switching and Juniper as internet routers.
I tried to replace 3725 router with 3845 and NM-1A-OC3-POM module. All PVCs work fine except PVC to the internet. When I send a normal 64-bytes ping from 3845 router to the network operators router I receive the replies with a variable delay. The ping packets above 368-bytes dont back.
I tried to use 12.4 mainline and T IOS software.
The ATM port and ATM PVC configuration is simple:
interface ATM1/0
no ip address
atm sonet stm-1
no atm ilmi-keepalive
!
interface ATM1/0.150 point-to-point
ip address xx.51.0.22 255.255.255.252
pvc 1/150
vbr-nrt 10000 10000
encapsulation aal5snap
!
!
Below are show commands:
rt1#show atm pvc 1/150
Description: N/A
ATM1/0.150: VCD: 3, VPI: 1, VCI: 150
VBR-NRT, PeakRate: 10000 (23585 cps), Average Rate: 10000 (23585 cps) Burst
Cells: 0 AAL5-LLC/SNAP, etype:0x0, Flags: 0x20, 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 ILMI VC status: Not Managed InARP frequency: 15
minutes(s) Transmit priority 3
InPkts: 9605, OutPkts: 7832, InBytes: 2891521, OutBytes: 2643120
InPRoc: 8226, OutPRoc: 7832
InFast: 1379, OutFast: 0, InAS: 0, OutAS: 0
InPktDrops: 0, OutPktDrops: 0/0/0 (holdq/outputq/total)
CrcErrors: 0, SarTimeOuts: 0, OverSizedSDUs: 0, LengthViolation: 0,
CPIErrors: 0 Out CLP=1 Pkts: 0 OAM cells received: 0
F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0
F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0 OAM cells sent: 0
F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0
F4 OutEndloop: 0, F4 OutSegloop: 0, F4 OutRDI: 0 OAM cell drops: 0
Status: UP
rt1#
rt1#show int atm 1/0
ATM1/0 is up, line protocol is up
Hardware is CX27470 ATMOC3
MTU 4470 bytes, sub MTU 4470, BW 149760 Kbit, DLY 80 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ATM, loopback not set
Encapsulation(s): AAL5
1023 maximum active VCs, 2 current VCCs
VC Auto Creation Disabled.
VC idle disconnect time: 300 seconds
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: Per VC Queueing
5 minute input rate 259000 bits/sec, 79 packets/sec
5 minute output rate 256000 bits/sec, 64 packets/sec
131383 packets input, 37252655 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
101080 packets output, 35367634 bytes, 0 underruns
0 output errors, 0 collisions, 4 interface resets
0 output buffer failures, 0 output buffers swapped out rt1#
rt1#
03-08-2006 02:49 PM
Hi,
I've seen problems on some platforms/cards where a missing MBS parameter causes problems. Could you try the following config:
interface ATM1/0.150 point-to-point
ip address xx.51.0.22 255.255.255.252
pvc 1/150
vbr-nrt 10000 10000 1
encapsulation aal5snap
!
Hope that helps - pls rate the post if it does.
Paresh
05-29-2006 10:02 PM
I was having a similar problem.
My carrier Telstra Australia came up with the following:
Have you got a Cisco login if so have a look at this bug which effects
your IOS while not exactly the same scenario it is suspicious
http://www.cisco.com/cgi-bin/Support/Bugtool/onebug.pl?bugid=CSCsd31198&
cco_product=IOS&fset=&swver=12.4&keyw=atm&target=4&train=T
Symptoms: Packets may exceed the PCR, causing large packets to be
dropped by
an ATM switch.
Conditions: This symptom is observed when a VBR-nrt PVC is configured on
an
NM-1A-OC3-POM network module with the PCR identical to the SCR and when
the
cell delay variation tolerance (CDVT) is violated at low traffic rates.
The
symptom may also occur when a CBR PVC is configured on an NM-1A-OC3-POM
network module.
Workaround: Set the SCR to a slightly lower value than the PCR or do not
configure a CBR PVC. Verify that the SCR and PCR settings are correct by
entering the show controller atm
slot/port command and ensuring that the SCR is a value
other than 0, as in the following command output example:
Tx bytes (489890600), Tx packets (360325), PCR/SCR (10240/10230)
------------------------------------------------------------------------
------------------------------------------------------------------------
---
You may want to try as Cisco suggest to set the SCR below the PCR and
see how close you can approach to the 4096 value.
Regards
..Vince
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