From: Petr Lapukhov (petr@internetworkexpert.com)
Date: Thu Sep 25 2008 - 06:18:58 ART
First of all, you're trying to send packets to a broadcast IP address.
However, by default, IP SLA operation tries to establish a control
connection on a specific UDP port with the destination IP. So make sure you
specified "control disable" keyword. This will switch your IP SLA operation
to pure "traffic generator".
If you want to generate a packet stream of certain rate with IP SLA UDP
Jitter opertation, use the following information.
"interval" is the "inter-packet" gap that IP SLA uses to emit packets
"frequency" is how often the operation generates traffic bursts (groups of
packets)
"request-data-size" the amount of payload (does not account for L3/L2/L1
overhead!) sent in every packet
"num-packets" number of packets sent every "frequency" seconds
It is usually convenient to set "frequency" to 1 second and "interval" to
1ms. Thus you may regulate the require packet per second rate (e.g. 100
packets per second) and obtain bits per second value based on the formula:
bps = num-packets*(request-data-size+L3 overhead + L2 overhead)*8 (the
formula is aproximate, for inter-packet delay is 1ms, not zero!)
Just make sure it takes less than a second to serialize the packet burst
across the output interface :)
Aside from using IP SLA as traffic generator, you may use the followig
methods to produce controlled packet flows:
1) Generate a flood of ICMP packets (timeout = 0) and configure a
traffic-shaper (GTS/CBTS) to format the stream to desired parameters (rate,
burst)
2) Use the hidden "ttcp" command for traffic generation and thoroughput
measurements
http://www.cisco.com/en/US/tech/tk801/tk36/technologies_tech_note09186a0080094694.shtml
HTH
-- Petr Lapukhov, CCIE #16379 (R&S/Security/SP/Voice) petr@internetworkexpert.comInternetwork Expert, Inc. http://www.InternetworkExpert.com Toll Free: 877-224-8987 Outside US: 775-826-4344
2008/9/25 Bit Gossip <bit.gossip@chello.nl>
> Dear group, > I was trying to use ip-sla as traffic generator but I can get only > marginal amount of traffic no matter what I set in the num-packets: in > the example attached I configured num-packets 10000 but only a couple > seem to be sent for real, the remaining being skipped. > I am using dynamips, may this be the reason? > Thanks, > Bit. > > R0#show running-config | s ip sla > ip sla 10 > udp-jitter 192.168.255.255 20000 num-packets 10000 interval 4 > frequency 206 > ip sla schedule 10 life forever start-time now > > R0#show ip sla statistics 10 details > IPSLAs Latest Operation Statistics > > IPSLA operation id: 10 > Latest RTT: 5 milliseconds > Latest operation start time: *22:33:28.611 UTC Wed Sep 24 2008 > Latest operation return code: OK > RTT Values: > Number Of RTT: 2 RTT Min/Avg/Max: 4/5/7 > milliseconds > Latency one-way time: > Number of Latency one-way Samples: 0 > Source to Destination Latency one way Min/Avg/Max: 0/0/0 > milliseconds > Destination to Source Latency one way Min/Avg/Max: 0/0/0 > milliseconds > Source to Destination Latency one way Sum/Sum2: 0/0 > Destination to Source Latency one way Sum/Sum2: 0/0 > Jitter Time: > Number of SD Jitter Samples: 1 > Number of DS Jitter Samples: 1 > Source to Destination Jitter Min/Avg/Max: 0/0/0 milliseconds > Destination to Source Jitter Min/Avg/Max: 3/3/3 milliseconds > Source to destination positive jitter Min/Avg/Max: 0/0/0 > <...> > Interarrival jitterin: 0 > Over thresholds occurred: FALSE > Packet Loss Values: > Loss Source to Destination: 0 Loss Destination to > Source: > 0 > Out Of Sequence: 0 Tail Drop: 0 Packet Late Arrival: 0 > Packet Skipped: 9998 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< > Voice Score Values: > Calculated Planning Impairment Factor (ICPIF): 0 > Mean Opinion Score (MOS): 0 > Number of successes: 4 > Number of failures: 0 > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html
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