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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 78 Configuring Cisco IOS IP SLA Operations
Configuring IP SLAs Operations
To configure the IP SLAs responder on the target device (the operational target), perform this task:
To disable the IP SLAs responder, enter the
no ip sla responder
global configuration command. This
example shows how to configure the device as a responder for the UDP jitter IP SLAs operation in the
next procedure:
Switch(config)#
ip sla responder udp-echo 172.29.139.134 5000
Analyzing IP Service Levels by Using the UDP Jitter Operation
Jitter means interpacket delay variance. When multiple packets are sent consecutively 10 ms apart from
source to destination, if the network is behaving correctly, the destination should receive them 10 ms
apart. But if there are delays in the network (like queuing, arriving through alternate routes, and so on)
the arrival delay between packets might be more than or less than 10 ms with a positive jitter value
meaning that the packets arrived more than 10 ms apart. If the packets arrive 12 ms apart, positive jitter
is 2 ms; if the packets arrive 8 ms apart, negative jitter is 2 ms. For delay-sensitive networks, positive
jitter values are undesirable, and a jitter value of 0 is ideal.
In addition to monitoring jitter, the IP SLAs UDP jitter operation can be used as a multipurpose data
gathering operation. The packets IP SLAs generates carry packet sending and receiving sequence
information and sending and receiving time stamps from the source and the operational target. Based on
these, UDP jitter operations measure this data:
•
Per-direction jitter (source to destination and destination to source)
•
Per-direction packet-loss
•
Per-direction delay (one-way delay)
•
Round-trip delay (average round-trip time)
Because the paths for the sending and receiving of data can be different (asymmetric), you can use the
per-direction data to more readily identify where congestion or other problems are occurring in the
network.
Command
Purpose
Step 1
configure terminal
Enters global configuration mode.
Step 2
ip sla responder
{
tcp-connect
|
udp-echo
}
ipaddress
ip-address
port
port-number
Configures the switch as an IP SLAs responder.
The keywords have these meanings:
•
tcp-connect
—Enable the responder for TCP connect operations.
•
udp-echo
—Enable the responder for User Datagram Protocol (UDP)
echo or jitter operations.
•
ipaddress
ip-address
—Enter the destination IP address.
•
port
port-number
—Enter the destination port number.
Note
The IP address and port number must match those configured on
the source device for the IP SLAs operation.
Step 3
end
Returns to privileged EXEC mode.
Step 4
show ip sla responder
Verifies the IP SLAs responder configuration on the device.
Step 5
copy running-config startup-config
(Optional) Saves your entries in the configuration file.
Summary of Contents for Catalyst 4500 Series
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