CCNP Switch Lab 5-2 IP Service Level Agreements in a Campus Environment

CCNP Switch Lab 5-2 IP Service Level Agreements in a Campus Environment

Topology

Objectives

  • Configure trunking, VTP, and SVIs.
  • Implement IP SLAs to monitor various network performance characteristics.

Background
Cisco IOS IP service level agreements (SLAs) allow users to monitor network performance between Cisco devices (switches or routers) or from a Cisco device to a remote IP device. Cisco IOS IP SLAs can be applied to VoIP and video applications as well as monitoring end-to-end IP network performance. In this lab, you configure trunking, VTP, and SVIs. You configure IP SLA monitors to test ICMP echo network performance between DLS1 and each host. You also configure IP SLA monitors to test jitter between DLS1 and the access layer switches ALS1 and ALS2.

Note: This lab uses Cisco WS-C2960-24TT-L switches with the Cisco IOS image c2960-lanbasek9-mz.122-
46.SE.bin, and Catalyst 3560-24PS with the Cisco IOS image c3560-advipservicesk9-mz.122-46.SE.bin. You
can use other switches (such as 2950 or 3550) and Cisco IOS Software versions if they have comparable
capabilities and features. Depending on the switch model and Cisco IOS Software version, the commands
available and output produced might vary from what is shown in this lab.

Required Resources

  • 2 switches (Cisco 2960 with the Cisco IOS Release 12.2(46)SE C2960-LANBASEK9-M image or comparable)
  • 1 switch (Cisco 3560 with the Cisco IOS Release 12.2(46)SE C3560-ADVIPSERVICESK9-mz image or comparable)
  • Ethernet and console cables

Step 1: Prepare the switches for the lab.

Erase the startup configuration, delete the vlan.dat file, and reload the switches. Refer to Lab 1 -1 “Clearing a Switch” and Lab 1 -2 “Clearing a Switch Connected to a Larger Network” to prepare the switches for this lab. Cable the equipment as shown.

Step 2: Configure host PCs.

Configure PCs Host A and Host B with the IP address and subnet mask shown in the topology. Host A is in VLAN 100 with a default gateway of 172.16.100.1 . Host B is in VLAN 200 with a default gateway of 172.16.200.1 .

Step 3: Configure basic switch parameters.

Configure the hostname, password, and, optionally, remote access on each switch.

Configure a management IP address on VLAN 1 for each of the three switches according to the diagram.

Configure default gateways on the access layer switches. The distribution layer switch will not use a default gateway because it acts as a Layer 3 device. The access layer switches act as Layer 2 devices and need a default gateway to send traffic off of the local subnet for the management VLAN.

Step 4: Configure trunks and EtherChannels between switches.

To distribute VLAN and VTP information, trunks are needed between the three switches. Configure these trunks according to the diagram. EtherChannel is used for these trunks.

Note: It is good practice to shut down the interfaces on both sides of the link before a port channel is created and then reenable them after the port channel is configured.

Configure the trunks and EtherChannel from DLS1 to ALS1.

Creating a port-channel interface Port-channel 1

Configure the trunks and EtherChannel from DLS1 to ALS2.

Creating a port-channel interface Port-channel 2

Configure the trunks and EtherChannel between ALS1 and DLS1 and between ALS1 and ALS2.

Creating a port-channel interface Port-channel 1

Creating a port-channel interface Port-channel 2
Configure the trunks and EtherChannel between ALS2 and DLS1 and between ALS2 and ALS1.

Creating a port-channel interface Port-channel 1

Creating a port-channel interface Port-channel 2

Step 5: Configure VTP on ALS1 and ALS2.

Change the VTP mode of ALS1 and ALS2 to client.

Step 6: Configure VTP on DLS1.

Create the VTP domain on DLS1, and create VLANs 100 and 200 for the domain.

Step 7: Configure access ports.
Configure the host ports for the appropriate VLANs according to the diagram.

Step 8: Configure VLAN interfaces and enable routing.

On DLS1, create the SVIs for VLANs 100 and 200. Note that the corresponding Layer 2 VLANs must be
configured for the Layer 3 SVIs to activate. This was done in Step 6.

The ip routing command is also needed to allow the DLS1 switch to act as a Layer 3 device to route between these VLANs. Because the VLANs are all considered directly connected, a routing protocol is not needed at this time. The default configuration on 3560 switches is no ip routing.

Run the following Tcl script on DLS1 to verify full connectivity. If these pings are not successful, troubleshoot.

Note: Tcl is only supported on DLS1.

Step 9: Configure Cisco IOS IP SLA responders.

IP SLA responders are Cisco IOS devices that support the IP SLA control protocol. An IP SLA responder uses the Cisco IOS IP SLA Control Protocol for notification configuration and on which port to listen and respond. Some operations, such as ICMP echo, do not require a dedicated IP SLA responder. Use the ip sla responder command on ALS1 and ALS2 to enable sending and receiving IP SLAs control packets.

Note: This command replaces the ip sla monitor responder command. All commands that used to begin with “ip sla monitor” now begin with “ip sla” (without “monitor”).

Configure ALS1 and ALS2 as IP SLA responders for UDP jitter using the ip sla responder udp-echo ipaddress command. Specify the IP address of DLS1 VLAN 1 to act as the destination IP address for the reflected UDP traffic on both ALS1 and ALS2.

Step 10: Configure the Cisco IOS IP SLA source to measure network performance.
IP SLA uses generated traffic to measure network performance between two networking devices. On DLS1, create an IP SLA operation and enter IP SLA configuration mode with the ip sla operationnumber command.

Configure an IP SLA ICMP echo operation using the icmp-echo command in IP SLA configuration mode. The IP SLA ICMP echo operation does not require a dedicated Cisco IOS IP SLA responder (the destination device can be a non-Cisco device, such as a PC). By default, the ICMP operation repeats every 60 seconds. On DLS1, for ICMP echo operation 1, specify the IP address of Host A as the target. For ICMP echo operation 2, specify the IP address of Host B as the target.

Jitter means inter-packet delay variance. UDP-based voice traffic associated with IP phone and PC softphone applications at the access layer require strict adherence to delay and jitter thresholds. To configure an IP SLA UDP jitter operation, use the udp-jitter command in IP SLA configuration mode. By default, the UDP jitter operation repeats every 60 seconds. For UDP jitter operation 3, specify the destination IP address of the ALS1 VLAN 1 interface as the target. For operation 4, specify the destination IP address of the ALS2 VLAN 1 interface as the target. The IP SLA communication port is 5000 for both operations.

Schedule the IP SLAs operations to run indefinitely beginning immediately using the ip sla schedule global configuration mode command.

Step 1 1 : Monitor IP SLAs operations.

View the IP SLA configuration for IP SLA 1 on DLS1 . The output for IP SLA 2 is similar.

What type of operation is being performed with IP SLA 1 ?
ICMP echo request

View the IP SLA configuration for IP SLA 3 on DLS1 . The output for IP SLA 4 is similar.

What type of operation is being performed with IP SLA 3?
udp jitter

Display global information about Cisco IOS IP SLAs on DLS1 .

Display information about Cisco IOS IP SLA responders on ALS1 . The ALS2 output is similar.

Display IP SLA statistics on DLS1 for IP SLA 1 . The IP SLA 2 output is similar.

From this output, you can see that the latest round-trip time (RTT) for SLA operation Index 1 (icmp-echo) is 1 millisecond (ms). The number of packets sent successfully from DLS1 to PC Host A was 15, and there was one failure. Display IP SLA statistics on DLS1 for IP SLA 3. The IP SLA 4 output is similar.

From this output, you can see that the latest RTT for SLA operation Index 3 (udp-jitter) is 3 ms. Jitter time from source to destination and from destination to source is averaging 1 ms, which is acceptable for voice applications. The number of packets sent successfully from DLS1 to ALS1 was 14, and there were no failures. Disable interface VLAN 1 on ALS1 using the shutdown command.

Allow a few minutes to pass and then issue the show ip sla statistics 3 command on DLS1 . The output should look similar to the following.

If there is a connectivity problem between IP SLA source DLS1 and responder ALS1 or ALS2, the communication to the responder will be lost and statistics will cease to be collected, except for the number of failed tests.

Note: The IP SLA itself is an additional task that must be performed by the switch CPU. A large number of intensive SLAs could create a significant burden on the CPU, possibly interfering with other switch functions and having detrimental impact on the overall device performance. Therefore, you should carefully evaluate the benefits of running IP SLAs. The CPU load should be monitored after the SLAs are deployed to verify that they do not stress the device’s CPU above safe limits.

Device Configurations (Instructor version)

Switch DLS1

Switch ALS1

Switch ALS2

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