Lab 10.2.8: Custom Queuing

Objective:

  • To prioritize traffic between the Houston router and the Orlando router, using custom queuing.

Scenario:

Our company has given us the task of connecting our Houston office with the Orlando office via Frame Relay. It has been determined that we need to have a strict queuing policy for traffic going across this link. Based on a network traffic analysis we conducted at peak operating times, we have determined that the network users are continually transferring files back and forth across this link, using FTP. The company has just put in new Voice Over IP equipment and are having problems with the connection across the link during peak times. The company also has internal web servers at both sides of the frame relay link, which contain important information that is used by both sides of the link. Access to these web servers, have been suffering due to the large file transfers. It has been determined that the voice traffic is the most critical information on the link, and that FTP and HTTP have the same importance. Also, all other traffic should be accounted for and, as a whole, have the same importance as FTP or HTTP. Basically VoIP should get 40 percent of the bandwidth, FTP 20 percent, HTTP 20 percent, and everything else 20 percent. It is our responsibility to connect these two routers together and configure custom queuing correctly.

Lab Tasks:

  1. Cable the lab as shown in the diagram.
  2. The first router to be configured is the Houston router. Log into the router and enter global configuration mode.
  3. Configure the following basic information into the Houston router:
  • Configure the hostname Houston on the router.
  • Configure the router to prevent the lookup of misspelled words.
  • Configure IGRP routing with the AS# 777. 
  • Configure the enable password to be cisco.
  • Configure the Ethernet 0 or Fast Ethernet 0/0 interface with the IP address 172.16.16.1/24.
  1. The next step is to configure the Frame Relay connection on the Houston router from the Serial 0 or Serial 0/0 interface configuration:
  • Configure the IP address to 172.17.17.17/24.
  • Configure the encapsulation type, DLCI, and LMI type.

What is the command to set the LMI type?

  1. Next, Configure the following basic information into the Orlando router:
  • Configure the hostname Orlando on the router.
  • Configure the router to prevent the lookup of misspelled words.
  • Configure IGRP routing with the AS# 777. 

On which networks do we want to enable IP routing?

  • Configure the enable password to be cisco.
  • Configure the Ethernet 0 or Fast Ethernet 0/0 interface with the IP address 172.20.20.1/24.
  1. The next step is to configure the Frame Relay connection on the Orlando router from the Serial 0 or Serial 0/0 interface configuration:
  • Configure the IP address to 172.17.17.18/24.
  • Configure the encapsulation type, DLCI, and LMI type.

Don’t forget the no shutdown command on the interfaces.

  1. Before configuring Custom Queuing on the routers, test your configurations by pinging the other router. This way you are insuring that your basic configuration is correct before changing it.
  2. Verify current queueing method in use
  • Enter the show interfaces command.

In the information returned by the router, what does the router say the queueing method is for Serial 0 or Serial 0/0 interface?

  1. Configure Custom Queuing on both the Houston, and the Orlando routers. We have determined, based on the applications in use, that VoIP traffic should have 40% of the bandwidth, FTP 20%, HTTP 20%, and all other traffic 20%. Custom queuing can put traffic into queues based on interface, protocol, or an access list. Since VoIP uses both TCP for the call setup and UDP for the call itself, we will use an access list to allow just the traffic that we want.

Houston(config)#access-list 101 permit tcp any any eq 1720
Houston(config)#access-list 101 permit udp any any range 16380 16480

Orlando(config)#access-list 111 permit tcp any any eq 1720
Orlando(config)#access-list 111 permit udp any any range 16380 16480

Note: We are using different access list numbers on the different routers to help differentiate between the routers, but could have used any valid extended ip access list number(100-199).

  1. Once we have configured the access lists, we need to configure our custom queue list for each of the routers. The custom queue list should have a queue for each of the traffic types that we want to control. We will be using the default queue to group all the traffic that is not VoIP, FTP, or HTTP.The following commands will be used to configure the router:

Houston(config)#queue-list 1 protocol ip 1 list 101 
Houston(config)#queue-list 1 protocol ip 2 tcp ftp
Houston(config)#queue-list 1 protocol ip 3 tcp www
Houston(config)#queue-list 1 default 4

Orlando(config)#queue-list 2 protocol ip 1 list 111 
Orlando(config)#queue-list 2 protocol ip 2 tcp ftp
Orlando(config)#queue-list 2 protocol ip 3 tcp www
Orlando(config)#queue-list 2 default 4

Note: We are using different queue list numbers on the different routers to help differentiate between the routers, but could have used any valid queue list number.

How many custom queue lists can we have on a router?

How many custom queues can we have in each custom queue list?



Custom queuing works on a round-robin basis. It first services queue 1, then queue 2, etc. until all of the configured queues have been serviced, then starts over again.

  1. The next step is to configure the service threshold per queue. This is how we give VoIP more bandwidth than anything else. We want VoIP to have twice as much bandwidth as FTP, or HTTP. If the FTP or HTTP default packet size is 1500 bytes, then we want VoIP to be able to output twice that amount or 3000 bytes for each 1500bytes of FTP or HTTP traffic. 3000 bytes of VoIP, 1500 bytes of FTP, 1500 bytes of HTTP, 1500 bytes of everything else, works out to 40%, 20%, 20%, and 20% respectively. The following commands will configure this for us.

Houston(config)#queue-list 1 queue 1 byte-count 3000
Houston(config)#queue-list 1 queue 2 byte-count 1500
Houston(config)#queue-list 1 queue 3 byte-count 1500
Houston(config)#queue-list 1 queue 4 byte-count 1500

Orlando(config)#queue-list 2 queue 1 byte-count 3000
Orlando(config)#queue-list 2 queue 2 byte-count 1500
Orlando(config)#queue-list 2 queue 3 byte-count 1500
Orlando(config)#queue-list 2 queue 4 byte-count 1500

  1. The final step in configuring our custom queuing list is to apply the list to an interface. Since our WAN interface is where we want to prioritize traffic, we will be applying it to the Serial 0 or Serial 0/0 interface on each of the routers as follows:

Houston(config)#interface serial 0
Houston(config-if)#custom-queue-list 1

Orlando(config)#interface serial 0/0
Orlando(config-if)#custom-queue-list 2

  1. Finally, we need to check to make sure that the routers are using custom queuing and that it is operating correctly. Issue the following commands and observe the responses from the router.

Houston#show queue serial 0
Orlando#show queue serial 0/0

What did the routers respond with?

Houston#show queueing custom
Orlando#show queueing custom

What did the routers respond with?

  1. Optional challenge step to test the operation of CQ. From the workstation/server connected to the Houston router, initiate a large file transfer from the workstation/server connected to the Orlando router. Now initiate a continuous ping from Orlando workstation to the Houston workstation. Next initiate a telnet session between the two workstations/servers. If time and money permit, also initiate a VoIP call across the Frame Relay link. Enter show queueing custom command on each of the routers.

What did the router respond with?

How has this response changed from the first time that you issued the show queueing custom command?

Change the queues so that FTP has 60%, VoIP has 10%, and everything else has 30%. Retry the test as described previously. Enter show queueing Custom command on each of the routers.

What did the router respond with?

How has this response changed from the first time that you issued the show queueing custom command?



How has this response changed from the second time that you issued the
show queueing custom command?