Re: Does 64Kbps Leased Ckt. support >64Kbps ???

dinekal · ‎09-11-2002

Hello,

We are one among the ISPs , supporting dedicated circuit connection. A chaotic nature of these leased circuits is, we often happened to see more bandwidth utilization than the commited bandwidth by the leased clients.

I appreciate if any of you guys address this problem.

Here the the serial interface output goes:

AS01>sh int ser

AS01>sh int serial 1/1/3:1

Serial1/1/3:1 is up, line protocol is up

Hardware is DS-E1

Interface is unnumbered. Using address of Loopback0

MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,

reliability 255/255, txload 38/255, rxload 59/255

Encapsulation HDLC, loopback not set, keepalive set (10 sec)

Last input 00:00:05, output 00:00:00, output hang never

Last clearing of "show interface" counters 15:39:31

Queueing strategy: fifo

Output queue 0/40, 42791 drops; input queue 0/75, 6601 drops

5 minute input rate 15000 bits/sec, 15 packets/sec

5 minute output rate 74000 bits/sec, 12 packets/sec

510674 packets input, 57367593 bytes, 0 no buffer

Received 0 broadcasts, 922 runts, 0 giants, 0 throttles

6601 input errors, 1175 CRC, 5176 frame, 0 overrun, 0 ignored, 3194 abort

429423 packets output, 315626652 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions no alarm present

Timeslot(s) Used:2, subrate: 64Kb/s, transmit delay is 0 flags

dinekal · ‎09-17-2002

I've have been waiting for your valuable answers, any of you guys could address this issue. How does a 64Kbps interface could show more bandwidth utilization as shown in my previous post. Even if you change the "load interval" for the interface it does not help us.

ckossmey · ‎09-17-2002

Configuration information is very helpful for these cases.

At a minimum, include the configuration for the controller and the interface and we might be able to help you better.

Changing the load interval should not, as you observed, change anything.

Keep in mind, the "bandwidth xxx" command under the serial interface does nothing to restrict the rate data is transmitted out, or received on, an interface.

Regards,

Clay

dinekal · ‎09-17-2002

Hi Clay,

Here the configuration goes, can you pls. help me out some way

Thanks,

Dinesh

**********************************************

Building configuration...

Current configuration:

!

version 11.3

service timestamps debug datetime show-timezone

service timestamps log datetime show-timezone

service password-encryption

controller E1 1/1/4

framing NO-CRC4

channel-group 0 timeslots 1

channel-group 1 timeslots 2

channel-group 2 timeslots 3

channel-group 3 timeslots 4

channel-group 4 timeslots 5

channel-group 6 timeslots 7

channel-group 7 timeslots 8

channel-group 8 timeslots 9

!

controller E1 1/1/5 !

!

interface Serial1/1/4:3

ip unnumbered Loopback0

encapsulation ppp

ip mroute-cache

no logging event link-status

load-interval 30

no cdp enable

end

!

interface Serial1/1/4:3

ip unnumbered Loopback0

no logging event link-status

no cdp enable

mljohnson · ‎09-17-2002

This is a bit of speculation on my part, but note the high amount (10%) of output drops. With this being a channelized DS0, we will only be able to fill the 64K pipe and no more. However, it may be that the output rate is computed for channelized interfaces before drops are recorded rather than after; so the 74K output rate is, as expected, too much, and therefore packets will be dropped due to the HW buffers being overrun. You might ensure that you have FS enabled, that you have recent code to avoid any bugs, and check out "sh int serial 1/1/3:1switch" to see if everything is being at least fast switched.

dinekal · ‎09-17-2002

Hi Johnson,

We changed to fast switiching, however it doesn't help. Do you think any change in buffer allocation or buffer tuning would help?. As per Cisco documentation Outqueue drops are not vulnerable under high bandwidth utilization, but we happened to see INPUT QUEUE DROPS too at very high utilization , not encouraging. Can you pls. help me out..

Here my configuration and output results goes....

**********************************************

Building configuration...

Current configuration:

!

version 11.3

service timestamps debug datetime show-timezone

service timestamps log datetime show-timezone

service password-encryption

controller E1 1/1/4

framing NO-CRC4

channel-group 0 timeslots 1

channel-group 1 timeslots 2

channel-group 2 timeslots 3

channel-group 3 timeslots 4

channel-group 4 timeslots 5

channel-group 6 timeslots 7

channel-group 7 timeslots 8

channel-group 8 timeslots 9

!

controller E1 1/1/5 !

!

interface Serial1/1/4:3

ip unnumbered Loopback0

encapsulation ppp

ip mroute-cache

no logging event link-status

load-interval 30

no cdp enable

end

!

AS01>sh int serial 1/1/4:3

Serial1/1/4:3 is up, line protocol is up

Hardware is DS-E1

Description: *** B I M ***

Interface is unnumbered. Using address of Loopback0

MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,

reliability 255/255, txload 255/255, rxload 91/255

Encapsulation PPP, loopback not set, keepalive set (10 sec)

LCP Open

Open: IPCP

Last input 00:00:01, output 00:00:00, output hang never

Last clearing of "show interface" counters 00:17:29

Queueing strategy: fifo

Output queue 0/40, 3333 drops; input queue 0/75, 107 drops

30 second input rate 23000 bits/sec, 17 packets/sec

30 second output rate 80000 bits/sec, 16 packets/sec

14768 packets input, 2140875 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

107 input errors, 14 CRC, 46 frame, 0 overrun, 0 ignored, 23 abort

15258 packets output, 10133611 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions no alarm present

Timeslot(s) Used:4, subrate: 64Kb/s, transmit delay is 0 flags