Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
New Member

How do I tell if I'm bursting using this ATM config .

On a 7206 router with a DS3 ATM interface, here is the config:

interface ATM1/0

no ip address

atm scrambling cell-payload

atm framing cbitplcp

no atm ilmi-keepalive

!

interface ATM1/0.132 point-to-point

ip address xxx.xxx.xxx.xxx/xx

pvc 1/32

ubr 10000

oam-pvc manage

Here are some outputs:

ROC-RT7206B-CR#sh atm int atm1/0.132

Interface ATM1/0:

AAL enabled: AAL5 , Maximum VCs: 4096, Current VCCs: 1

Maximum Transmit Channels: 0

Max. Datagram Size: 4528

PLIM Type: DS3 - 45000Kbps, Framing is C-bit PLCP,

DS3 lbo: short, TX clocking: LINE

Cell-payload scrambling: ON

151215 input, 455534 output, 128144954 IN fast, 125480176 OUT fast, 0 out drop

Avail bw = 45000

Config. is ACTIVE

-------------------------------------------------

ROC-RT7206B-CR#sh atm pvc

VCD / Peak Avg/Min Burst

Interface Name VPI VCI Type Encaps SC Kbps Kbps Cells Sts

1/0.132 1 1 32 PVC SNAP UBR 10000 UP

-----------------------------------------------------------

ROC-RT7206B-CR#sh atm pvc 1/32

ATM1/0.132: VCD: 1, VPI: 1, VCI: 32

UBR, PeakRate: 10000

AAL5-LLC/SNAP, etype:0x0, Flags: 0x20, VCmode: 0x0

OAM frequency: 10 second(s), OAM retry frequency: 1 second(s), OAM retry frequency: 1 second(s)

OAM up retry count: 3, OAM down retry count: 5

OAM Loopback status: OAM Received

OAM VC state: Verified

ILMI VC state: Not Managed

VC is managed by OAM.

InARP frequency: 15 minutes(s)

Transmit priority 4

InPkts: 128371886, OutPkts: 126012967, InBytes: 3379594291, OutBytes: 4010575291

InPRoc: 49328, OutPRoc: 353999

InFast: 128322431, OutFast: 125658422, InAS: 0, OutAS: 0

InPktDrops: 0, OutPktDrops: 0

CrcErrors: 0, SarTimeOuts: 0, OverSizedSDUs: 0

OAM cells received: 101994

F5 InEndloop: 101994, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0

F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0

OAM cells sent: 101995

F5 OutEndloop: 101995, F5 OutSegloop: 0, F5 OutRDI: 0

F4 OutEndloop: 0, F4 OutSegloop: 0, F4 OutRDI: 0

OAM cell drops: 0

Status: UP

1. How do I tell if this circuit is bursting above the 10MB limit?

2. Without any burst or cell rate fields configured in the PVC statement, is this circuit wide open to be able to burst the full DS3?

5 REPLIES
Silver

Re: How do I tell if I'm bursting using this ATM config .

Answers to your questions.

1. Your "show atm pvc 1/32 would show OutPktDrops if you were dropping anything due to your PCR setting of 10000. So it does not appear that you are dropping due to shaping.

2. yes, the PCR setting for UBR is not required and without it it would assume that the entire available BW it could consume. So it would be able to spike to the entire DS3 rate.

Here is a link with more information about UBR and how it is handled if you are interested.

http://www.cisco.com/en/US/partner/tech/tk39/tk51/technologies_tech_note09186a00800a4837.shtml

Hope this helps,

Don

New Member

Re: How do I tell if I'm bursting using this ATM config .

Thanks - that article helps to explain UBR. I have one more question.

I checked another router configured for vbr-nrt VC's, and noticed that the 'Avail bw =' doesn't show the correct bandwidth. It is supposed to subtract the vbr-nrt SCR number from the physical interface size, but it doesn't. Here is the config and output:

interface ATM1/0.132 point-to-point

description ATM DS3 to OMC

bandwidth 10000

ip address xxx.xxx.xxx.xxx 255.255.255.128

no ip mroute-cache

pvc ROC-OMC-data 1/32

vbr-nrt 10000 10000 32

oam-pvc manage

encapsulation aal5snap

ROC-RT7206A-ATM#sh atm int atm 1/0

Interface ATM1/0:

AAL enabled: AAL5 , Maximum VCs: 4096, Current VCCs: 8

Maximum Transmit Channels: 0

Max. Datagram Size: 4528

PLIM Type: SONET - 155000Kbps, TX clocking: LINE

Cell-payload scrambling: ON

sts-stream scrambling: ON

2140416163 input, 2274155556 output, 470420126 IN fast, 713004668 OUT fast, 0 out drop

Avail bw = 155000

Config. is ACTIVE

Shouldn't the 'Avail bw=' be 145000?

The IOS on the 7206 is 12.1(16)

Silver

Re: How do I tell if I'm bursting using this ATM config .

Yes, this should've reduced your Avail BW unless this Ds3 interface does not support this type of shaping.. Might also be a defect.

Can you do a show atm pvc for this vbr-nrt PVC just to ensure it's up. This might be the issue as well.

Regards,

Don

New Member

Re: How do I tell if I'm bursting using this ATM config .

Actually this is an OC3 interface. (The description of the subinterface is incorrect.) I actually have six PVC's configured on this interface, all at 10MB. And all PVCs are 'UP'. Here is the entire interface config along with a 'show atm pvc':

interface ATM1/0

description N/A

no ip address

no ip route-cache cef

no ip mroute-cache

load-interval 30

atm pvc 5 0 5 qsaal

atm pvc 10 0 16 ilmi

no atm ilmi-keepalive

!

interface ATM1/0.132 point-to-point

description ATM DS3 to OMC

bandwidth 10000

ip address xxx.xxx.xxx.xxx 255.255.255.128

no ip mroute-cache

pvc ROC-OMC-data 1/32

vbr-nrt 10000 10000 32

oam-pvc manage

encapsulation aal5snap

!

interface ATM1/0.232 point-to-point

description ATM DS3 to TSC

bandwidth 10000

ip address xxx.xxx.xxx.xxx 255.255.255.128

no ip mroute-cache

pvc ROC-TSC-data 2/32

vbr-nrt 10000 10000 32

oam-pvc manage

encapsulation aal5snap

!

interface ATM1/0.332 point-to-point

description ATM DS3 to ACC

bandwidth 10000

ip address xxx.xxx.xxx.xxx 255.255.255.128

no ip mroute-cache

pvc ROC-ACC-data 3/32

vbr-nrt 10000 10000 32

oam-pvc manage

encapsulation aal5snap

!

interface ATM1/0.432 point-to-point

description ATM DS3 to CMB

bandwidth 10000

ip address xxx.xxx.xxx.xxx 255.255.255.128

no ip mroute-cache

pvc ROC-CMB-data 4/32

vbr-nrt 10000 10000 32

oam-pvc manage

encapsulation aal5snap

!

interface ATM1/0.532 point-to-point

description ATM DS3 to ESH

bandwidth 10000

ip address xxx.xxx.xxx.xxx 255.255.255.128

no ip mroute-cache

pvc ROC-ESH-data 5/32

vbr-nrt 10000 10000 32

oam-pvc manage

encapsulation aal5snap

!

interface ATM1/0.632 point-to-point

description DS3 to ACN/Spokane

bandwidth 10000

ip address xxx.xxx.xxx.xxx 255.255.255.128

no ip mroute-cache

pvc ROC-SPK-data 6/32

vbr-nrt 10000 10000 32

oam-pvc manage

encapsulation aal5snap

----------------------------------------------------------

ROC-RT7206A-ATM#sh atm int atm 1/0

Interface ATM1/0:

AAL enabled: AAL5 , Maximum VCs: 4096, Current VCCs: 8

Maximum Transmit Channels: 0

Max. Datagram Size: 4528

PLIM Type: SONET - 155000Kbps, TX clocking: LINE

Cell-payload scrambling: ON

sts-stream scrambling: ON

2140446986 input, 2274199385 output, 493172364 IN fast, 737832927 OUT fast, 0 out drop

Avail bw = 155000

Config. is ACTIVE

--------------------------------------------------------------------

ROC-RT7206A-ATM#sh atm pvc

VCD / Peak Avg/Min Burst

Interface Name VPI VCI Type Encaps SC Kbps Kbps Cells Sts

1/0 5 0 5 PVC SAAL UBR 149760 UP

1/0 10 0 16 PVC ILMI UBR 149760 UP

1/0.132 ROC-OMC-da 1 32 PVC SNAP VBR 10000 10000 32 UP

1/0.232 ROC-TSC-da 2 32 PVC SNAP VBR 10000 10000 32 UP

1/0.332 ROC-ACC-da 3 32 PVC SNAP VBR 10000 10000 32 UP

1/0.432 ROC-CMB-da 4 32 PVC SNAP VBR 10000 10000 32 UP

1/0.532 ROC-ESH-da 5 32 PVC SNAP VBR 10000 10000 32 UP

1/0.632 ROC-SPK-da 6 32 PVC SNAP VBR 10000 10000 32 UP

So the avail bw should actually show 95000 instead of the full 155000 right?

Do I need to open of a TAC case to fget some help on this?

Silver

Re: How do I tell if I'm bursting using this ATM config .

I did a quick test with a 7500 /w a PA-A3 ATM port adapter (/w 12.0(21)ST3) and I was unable to get the Avail BW to reduce based on vbr-nrt SCR rates. I was however able to reduce Avail BW on LS1010 0C3 PAM, so looking again at the URL I sent you and looking at my test I am thinking that the Avail BW is a switching function since, it is the one doing the policing on ingress for your PVC's. You seem to be able to shape on output with your PA but it does not seem to adjust Avail BW. I also cannot find a link that says this is the way it is. If it is of big concern to you please open a Case with TAC. It will go to an ATM specialist team if needed. Those people are very good at ATM.

Hope this helps,

Don

96
Views
0
Helpful
5
Replies
CreatePlease to create content