8.2.1.5 Lab – Configure IP SLA ICMP Echo Answers

8.2.1.5 Lab – Configure IP SLA ICMP Echo (Instructor Version)

Instructor Note: Red font color or gray highlights indicate text that appears in the instructor copy only.

Topology

Addressing Table

Objectives

Part 1: Build the Network and Verify Connectivity
Part 2: Configure IP SLA ICMP Echo on R1
Part 3: Test and Monitor the IP SLA Operation

Background / Scenario

An outside vendor has been contracted to provide web services for your company. As the network administrator, you have been asked to monitor the vendor’s service. You decide to configure IP SLA to help with that task.

Note: The routers used with CCNA hands-on labs are Cisco 1941 Integrated Services Routers (ISRs) with Cisco IOS Release 15.2(4)M3 (universalk9 image). The switches used are Cisco Catalyst 2960s with Cisco IOS Release 15.0(2) (lanbasek9 image). Other routers, switches, and Cisco IOS versions can be used. Depending on the model and Cisco IOS version, the commands available and output produced might vary from what is shown in the labs. Refer to the Router Interface Summary Table at the end of this lab for the correct interface identifiers.

Note: Make sure that the routers and switches have been erased and have no startup configurations. If you are unsure, contact your instructor.

Instructor Note: Refer to the Instructor Lab Manual for the procedures to initialize and reload devices.

Required Resources

• 2 Router (Cisco 1941 with Cisco IOS Release 15.2(4)M3 universal image or comparable)
• Console cables to configure the Cisco IOS devices via the console ports
• Serial cable as shown in the topology

Part 1: Build the Network and Verify Connectivity

In Part 1, you will set up the network topology and configure basic settings, such as the interface IP addresses, static routing, device access, and passwords.

Step 1: Cable the network as shown in the topology.

Attach the devices as shown in the topology diagram, and cable as necessary.

Step 2: Initialize and reload the routers as necessary.

Step 3: Configure basic settings for R1.

a. Disable DNS lookup.

b. Configure the device name as shown in the topology.

c. Configure an IP address for the router as listed in the Addressing Table.

d. Assign class as the encrypted privileged EXEC mode password.

e. Assign cisco for the console and vty password, enable login.

f. Configure logging synchronous to prevent console messages from interrupting command entry.

g. Configure the default route for R1 to the ISP S0/0/0 IP address.

h. Copy the running configuration to the startup configuration.

Step 4: Copy and paste the configuration to the ISP router.

The ISP router configuration is provided below. Copy and paste this configuration into the ISP router. Loopback 0 is being used to simulate the Web server shown in the Topology.

hostname ISP
no ip domain lookup
interface Loopback0
 ip address 198.133.219.1 255.255.255.255
interface Serial0/0/0
 ip address 209.165.200.10 255.255.255.252
 no shut
end

Step 5: Verify connectivity.

a. From R1, you should be able to ping the ISP Serial interface IP address. Were all pings successful?
___________Yes

If the pings are not successful, troubleshoot the basic device configurations before continuing.

b. From R1, you should be able to ping the Web Server IP address. Were all pings successful?
___________Yes

If the pings are not successful, troubleshoot the basic device configurations before continuing.

Part 2: Configure IP SLA ICMP Echo on R1

In Part 2, you configure an IP SLA ICMP Echo operation on R1. Use the following parameters for this operation:

• Operation-number: 22
• ICMP Echo Destination Address: 198.133.219.1
• Frequency: 20 seconds
• Schedule Start: Now
• Schedule Life time: Forever

Step 1: Create an IP SLA Operation.

R1(config)# ip sla 22

Step 2: Configure the ICMP Echo Operation.

R1(config-ip-sla)# icmp-echo 198.133.219.1

Step 3: Set the rate the IP SLA operation repeats.

R1(config-ip-sla-echo)# frequency 20

Step 4: Schedule the IP SLA ICMP Echo operation.

R1(config)# ip sla schedule 22 start-time now life forever

Step 5: Use show command to verify the IP SLA configuration.

R1# show ip sla configuration  
IP SLAs Infrastructure Engine-III  
Entry number: 22  
Owner:   
Tag:   
Operation timeout (milliseconds): 5000  
Type of operation to perform: icmp-echo  
Target address/Source address: 198.133.219.1/0.0.0.0  
Type Of Service parameter: 0x0  
Request size (ARR data portion): 28  
Verify data: No  
Vrf Name:   
Schedule:  
   Operation frequency (seconds): 20  (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): 5000  
Distribution Statistics:
   Number of statistic hours kept: 2  
   Number of statistic distribution buckets kept: 1  
   Statistic distribution interval (milliseconds): 20  
Enhanced History:  
History Statistics:  
   Number of history Lives kept: 0  
   Number of history Buckets kept: 15  
   History Filter Type: None

Part 3: Test and Monitor the IP SLA Operation

In Part 3, you will simulate an outage of web services. This can be done by an administratively shutdown of the loopback 0 interface on the ISP router. You will then display the IP SLA operation statistics to monitorthe effect of this test.

Step 1: Shutdown the loopback 0 interface on the ISP router.

ISP(config)# interface Lo0
ISP(config-if)# shutdown
ISP(config-if)#
*Nov 28 14:00:52.823: %LINK-5-CHANGED: Interface Loopback0, changed state to
administratively down
*Nov 28 14:00:53.823: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0,
changed state to down
ISP(config-if)#

Note: Wait a few minutes before executing Step 2.

Step 2: Activate the loopback 0 interface on the ISP router.

R2(config-if)# no shutdown
R2(config-if)#
*Nov 28 14:04:23.263: %LINK-3-UPDOWN: Interface Loopback0, changed state to up
*Nov 28 14:04:24.263: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0,
changed state to up
R2(config-if)#

Step 3: Issue the command used to display the IP SLA operation statistics on R1.

R1# show ip sla statistics
IPSLAs Latest Operation Statistics

IPSLA operation id: 22
      Latest RTT: 1 milliseconds
Latest operation start time: 18:44:45 UTC Thu Jan 28 2016
Latest operation return code: OK
Number of successes: 103
Number of failures: 10
Operation time to live: Forever

Note: You should see a failure count greater than zero if you waited more than 20 seconds before re-activating the loopback 0 interface on the ISP router.

The IP SLA configured in Part 2 will run forever. How would you stop the IP SLA from running but still leave the IP SLA configured to use at a future time?
_______________________________________________________

R1(config)# no ip sla schedule 22

Reflection

Using the lab’s show ip sla statistics example, what does the failure count indicate about the Web Server?
_________________________________________________________
Answers will vary, but this number shows that the IP SLA ICMP Echo operation was not able to reach the Web Server 10 times since the start of the IP SLA monitoring operation. This can be interpreted that there has been approximately 3 minutes’ of interruptions in web services since Jan 28, 2016 6:45pm. However, it is not known if this was one long incident (approximately 3 minutes) or if it was multiple shorter incidents.

Router Interface Summary Table

Device Configs

Router R1

R1#show run
Building configuration...

Current configuration : 1577 bytes
!
version 15.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$papm$awGgHPitBMUA2.bImJtdp0
!
no aaa new-model
memory-size iomem 15
!
no ip domain lookup
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
redundancy
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
no ip address
shutdown
duplex auto
speed auto
!
interface GigabitEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
interface Serial0/0/0
ip address 209.165.200.9 255.255.255.252
clock rate 2000000
!
interface Serial0/0/1
no ip address
shutdown
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
ip route 0.0.0.0 0.0.0.0 209.165.200.10
!
ip sla 22
icmp-echo 198.133.219.1
frequency 20
ip sla schedule 22 life forever start-time now
!
control-plane
!
line con 0
password cisco
login
line aux 0
line 2
no activation-character
no exec
transport preferred none
transport output pad telnet rlogin lapb-ta mop udptn v120 ssh
stopbits 1
line vty 0 4
password cisco
login
transport input none
!
scheduler allocate 20000 1000
!
end

Router ISP

ISP# show run
Building configuration...

Current configuration : 1360 bytes
version 15.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname ISP
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
memory-size iomem 15
!
no ip domain lookup
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
cts logging verbose
!
redundancy
!
interface Loopback0
ip address 198.133.219.1 255.255.255.255
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
no ip address
shutdown
duplex auto
speed auto
!
interface GigabitEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
interface Serial0/0/0
ip address 209.165.200.10 255.255.255.252
!
interface Serial0/0/1
no ip address
shutdown
clock rate 125000
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
control-plane
!
line con 0
line aux 0
line 2
no activation-character
no exec
transport preferred none
transport output pad telnet rlogin lapb-ta mop udptn v120 ssh
stopbits 1
line vty 0 4
login
transport input none
!
scheduler allocate 20000 1000
!
end