12-02-2011 07:13 AM - edited 03-07-2019 03:42 AM
Hii everybody
Please consider the following:
R1(config)#ip sla 11
R1(config-ip-sla)#?
IP SLAs entry configuration commands:
dhcp DHCP Operation
dns DNS Query Operation
exit Exit Operation Configuration
frame-relay Frame-relay Operation
ftp FTP Operation
http HTTP Operation
icmp-echo ICMP Echo Operation
icmp-jitter ICMP Jitter Operation
mpls MPLS Operation
path-echo Path Discovered ICMP Echo Operation
path-jitter Path Discovered ICMP Jitter Operation
slm SLM Operation
tcp-connect TCP Connect Operation
udp-echo UDP Echo Operation
udp-jitter UDP Jitter Operation
voip Voice Over IP Operation
Following are the options under path-echo operation.
IP SLAs pathEcho Configuration Commands:
default Set a command to its defaults
exit Exit operation configuration
frequency Frequency of an operation
history History and Distribution Data
hops-of-statistics-kept Maximum number of statistics hops to capture
lsr-path Loose Source Routing Path
no Negate a command or set its defaults
owner Owner of Entry
paths-of-statistics-kept Maximum number of statistics paths to capture
request-data-size Request data size
samples-of-history-kept Maximum number of history samples to collect
tag User defined tag
threshold Operation threshold in milliseconds
timeout Timeout of an operation
tos Type Of Service
verify-data Verify data
vrf Configure IP SLAs for a VPN Routing/Forwarding
instance
I found similar options under "icmp-echo" operation. There are other operation such AS dHCP,DNS i was not able to configure and thus could not varify if similar options are available under them as well
My question is should I expect similar options under DNs,FTP Dhcp operations ?
======================================================================================
I configure icmp-echo operation under sla with threshold=20,
Below is output from "show ip sla config "
IP SLAs Infrastructure Engine-II
Entry number: 11
Owner:
Tag:
Type of operation to perform: icmp-echo
Target address/Source address: 200.200.200.2/200.200.200.1
Operation timeout (milliseconds): 5000
Type Of Service parameters: 0x0
Vrf Name:
Request size (ARR data portion): 28
Verify data: No
Schedule:
Operation frequency (seconds): 60 (not considered if randomly scheduled)
Next Scheduled Start Time: Start Time already passed
Group Scheduled : FALSE
Randomly Scheduled : FALSE
Life (seconds): Forever
Entry Ageout (seconds): never
Recurring (Starting Everyday): FALSE
Status of entry (SNMP RowStatus): Active
Threshold (milliseconds): 20
Distribution Statistics:
Number of statistic hours kept: 2
--More--
Below is the output of "show ip sla sta"
R1#show ip sla sta
Round Trip Time (RTT) for Index 11
Latest RTT: 168 milliseconds
Latest operation start time: *02:47:54.419 UTC Fri Mar 1 2002
Latest operation return code: Over threshold
Number of successes: 0
Number of failures: 3
Operation time to live: Forever
Here is my question
How the number of success is measured?
What does R1 take into account in order to consider the operation as success? Will R1 consider only RTT? Will R1 consider the reachability as success? Or will R1 consider both factors i.e RTT and reachability to consider the operation being successful?
Let me illustrate it .
Let say R1 is configured to perform icmp-echo SLA operation.
The configured RTT =20ms
R1 receives first icmp response with RTT=10ms
R1 receives second ICmp response with RTT=15 ms
R1 receives thired icmp response with RTT=27ms.
Now If I run " show ip sla sta on R1, What will I find against the field " number of success" in show ip sla sta command?
Will it be 3 because R1 sends three icmp echo request and get responses for them? Will it be 2 because 2 out of three icmp echo-response packets are received with RTT below the configured threshold?
Thanks and have a nice day
Solved! Go to Solution.
12-03-2011 07:15 PM
Hi Sarah,
How the number of success is measured?What does R1 take into account in order to consider the operation as success? Will R1 consider only RTT? Will R1 consider the reachability as success? Or will R1 consider both factors i.e RTT and reachability to consider the operation being successful?
Let me illustrate it .
Let say R1 is configured to perform icmp-echo SLA operation.
The configured RTT =20ms
R1 receives first icmp response with RTT=10ms
R1 receives second ICmp response with RTT=15 ms
R1 receives thired icmp response with RTT=27ms.
Now If I run " show ip sla sta on R1, What will I find against the field " number of success" in show ip sla sta command?
Will it be 3 because R1 sends three icmp echo request and get responses for them? Will it be 2 because 2 out of three icmp echo-response packets are received with RTT below the configured threshold?
Thanks and have a nice day
Its not entirely the reachability of the route . For that, you have something callled object tracking where you still use IP SLA etc but your prime concern is to know whether the destination is alive.
IP SLA's are most often used to for measuring performance like delay, jitter, latency etc by sending synthetic traffic across the link.. In your case if you have set the threshold for RTT=20ms and send receives 3 echo replies back(which means that the reachability is achieved) within that threshold then its considered as success. However, failure can mean 2 things. First , that the destination is not reachable( could be firewalls blocking icmps etc) essentially saying that the probes are not coming back and they will timeout. Second, as you mentioned the threshold in your case if the RTT=27ms then its a failure as the threshold you have set is 20ms. The IP SLA checks if the Latest RTT
If yes, then its a success otherwise its a failure.
HTH
Kishore
12-03-2011 07:15 PM
Hi Sarah,
How the number of success is measured?What does R1 take into account in order to consider the operation as success? Will R1 consider only RTT? Will R1 consider the reachability as success? Or will R1 consider both factors i.e RTT and reachability to consider the operation being successful?
Let me illustrate it .
Let say R1 is configured to perform icmp-echo SLA operation.
The configured RTT =20ms
R1 receives first icmp response with RTT=10ms
R1 receives second ICmp response with RTT=15 ms
R1 receives thired icmp response with RTT=27ms.
Now If I run " show ip sla sta on R1, What will I find against the field " number of success" in show ip sla sta command?
Will it be 3 because R1 sends three icmp echo request and get responses for them? Will it be 2 because 2 out of three icmp echo-response packets are received with RTT below the configured threshold?
Thanks and have a nice day
Its not entirely the reachability of the route . For that, you have something callled object tracking where you still use IP SLA etc but your prime concern is to know whether the destination is alive.
IP SLA's are most often used to for measuring performance like delay, jitter, latency etc by sending synthetic traffic across the link.. In your case if you have set the threshold for RTT=20ms and send receives 3 echo replies back(which means that the reachability is achieved) within that threshold then its considered as success. However, failure can mean 2 things. First , that the destination is not reachable( could be firewalls blocking icmps etc) essentially saying that the probes are not coming back and they will timeout. Second, as you mentioned the threshold in your case if the RTT=27ms then its a failure as the threshold you have set is 20ms. The IP SLA checks if the Latest RTT
If yes, then its a success otherwise its a failure.
HTH
Kishore
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