01-16-2007 08:12 AM - edited 03-05-2019 01:48 PM
Hi - I have a router configured with ATM IMA & 3 X ATM 2Mbps circuits which never reaches it's max 6Mbps bandwidth. I fully understand about IMA & ATM overhead and that I should not reach 6Mbps however I am only reaching 4.6Mbps. The router does have qos but the same problem occured before the qos was added. This problem also occurs on antoher IMA router elsewhere so I'm pretty sure it's not a code or hardware error. Here's the IMA config:
network-clock-participate wic 0
network-clock-participate wic 1
network-clock-participate aim 1
network-clock-select 1 E1 0/0
network-clock-select 2 E1 0/1
network-clock-select 3 E1 0/2
controller E1 0/0
mode atm aim 1
!
controller E1 0/1
mode atm aim 1
!
controller E1 0/2
mode atm aim 1
!
interface ATM0/0
no ip address
scrambling-payload
ima-group 1
no atm ilmi-keepalive
no fair-queue
interface ATM0/1
no ip address
scrambling-payload
ima-group 1
no atm ilmi-keepalive
no fair-queue
interface ATM0/2
no ip address
scrambling-payload
ima-group 1
no atm ilmi-keepalive
no fair-queue
!
interface ATM0/IMA1
no ip address
ip accounting precedence input
ip accounting precedence output
ip route-cache flow
no atm ilmi-keepalive
service-policy output qos
!
interface ATM0/IMA1.100 point-to-point
ip address x.x.x.x 255.255.255.252
ip accounting precedence input
ip accounting precedence output
ip nbar protocol-discovery
pvc 1/100
vc-hold-queue 1024
encapsulation aal5snap
Can you see any obvious mistakes that would explain the problem, or do you know of any known IMA additional configuration that may be required?
01-16-2007 08:25 AM
Hi,
how do you measure the maximum throughput? Is this application level like an FTP download? Or did you just do a "show interface"?
You are not too far from the theoretical limit taking into account ATM and IMA overhead. Accounting for the 40 Byte TCP/IP header and assuming an average packet size of 500 Bytes you would expect about the measured 4.6 Mbps.
How much would you expect based on your measurement method?
Regards, Martin
01-17-2007 02:05 AM
I am using MRTG & a Netflow application level server to measure the throughput. Maybe I have my calculations wrong, and I am no ATM expert (hence this post) but I was expecting a greater throughput.
01-27-2007 09:41 PM
chris,
mrtg gets its stats via snmp so what you see is the same as sh xxx command
i would suggest a little .exe program, one runs on one end and the other at the other in server mode. they pump packets and you get real time reading, it is called NetCPS.exe but I cant figure a way to post it here
NetCPS 1.0 - donated into the Public Domain (almost) by Jarle Aase
THIS PROGRAM IS NOT LISENCED TO GOVERNMENTAL OR MILITARY USE.
Usage: NetCPS.exe [options] [Remote host]
-Pn Port number. Default port is 4455
-server Server mode. (Default is client)
-mn Megabytes to transfer. Default is 100
Note: 'n' represents a number.
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