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service-level agreement's operations

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

1 ACCEPTED SOLUTION

Accepted Solutions

service-level agreement's operations

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

1 REPLY

service-level agreement's operations

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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