Lab 4.3.4 Exploring Network QoS
Step 1: Cable and configure the network
a. Connect and configure the devices in accordance with the given topology and configuration.
Routing will have to be configured across the serial WAN link to establish data communications.
Configure Telnet access on each router.
b. Ping between Host1 and Discovery Server to confirm network connectivity.
1) Confirm Application Layer connectivity by telnetting from R2 to R1.
2) Troubleshoot and establish connectivity if the pings or Telnet fail.
c. After confirming the initial configurations, maintain a console terminal session connection with R2.
Step 2: Examine priority queue commands
Configuring Priority Queueing
Configuring priority queueing (PQ) has two required steps and an optional third step:
1. Define the priority list (Required)
2. Assign the priority list to an Interface (Required)
3. Monitor priority queueing lists (Optional)
A priority list contains the definitions for a set of priority queues. The priority list specifies which queue a
packet will be placed in and, optionally, the maximum length of the different queues. To perform queueing
using a priority list, you must assign the list to an interface. The same priority list can be applied to multiple interfaces. Alternatively, you can create many different priority policies to apply to different interfaces.
Defining the Priority List
The priority list is defined by:
1. Assigning packets to priority queues
2. Specifying the maximum size of the priority queues (Optional)
Packets are assigned to priority queues based on the protocol type and the interface where the packets enter the router. The priority-list commands are read in order of appearance until a matching protocol or interface type is found. When a match is found, the packet is assigned to the appropriate queue and the search ends. Packets that do not match other assignment rules are assigned to the default queue. The following global configuration mode commands are used to specify in which queue a packet is placed. The command format is priority-list list-number Use a list-number of 1 and note the options available.
a. Enter the following command and note the options available.
FC-CPE-1(config)#priority-list 1 ?
default Set priority queue for
unspecified datagrams
interface Set priorities for packets
from a named interface
protocol priority queueing by protocol
queue-limit Set queue limits for
priority queues
b. Note some of the protocol options available.
FC-CPE-1(config)#priority-list 1 protocol ?
arp IP ARP
bridge Bridging
cdp Cisco Discovery Protocol
compressedtcp Compressed TCP (VJ)
http HTTP
ip IP
llc2 llc2
pad PAD links
pppoe PPP over Ethernet
snapshot Snapshot routing support
c. Note the IP protocol options available.
FC-CPE-1(config)#priority-list 1 protocol ip ?
high
medium
normal
low
d. Note the HTTP protocol options available.
FC-CPE-1(config)#priority-list 1 protocol http ?
high
medium
normal
low
e. Note the IP protocol high priority options available.
FC-CPE-1(config)#priority-list 1 protocol ip high ?
fragments Prioritize fragmented IP
packets
gt Prioritize packets greater
than a specified size
list To specify an access list
lt Prioritize packets less than a
specified size
tcp Prioritize TCP packets ‘to’ or
‘from’ the specified port
udp Prioritize UDP packets ‘to’ or
‘from’ the specified port<cr>
f. Note the IP protocol high priority TCP options available.
FC-CPE-1(config)#priority-list 1 protocol ip high tcp ?
<0-65535> Port number
domain Domain Name Service (53)
echo Echo (7)
ftp File Transfer Protocol (21)
ftp-data FTP data connections (20)
irc Internet Relay Chat (194)
nntp Network News Transport Protocol
(119)
pop3 Post Office Protocol v3 (110)
smtp Simple Mail Transport Protocol
(25)
telnet Telnet (23)
www World Wide Web (HTTP, 80)
Over 30 port/service options are available.
Step 3: Configure an example priority queue
From the global configuration mode, issue the following commands.
FC-CPE-1(config)#priority-list 1 protocol http high
FC-CPE-1(config)#priority-list 1 protocol ip normal tcp ftp
FC-CPE-1(config)#priority-list 1 protocol ip medium tcp telnet
What do these commands establish?
Sebuah daftar prioritas (nomor “1″) yang menetapkan paket HTTP yang akan ditandai sebagai prioritas tinggi, paket FTP rendah prioritas, dan Telnet paket sebagai prioritas menengah.
Step 4: Assign the priority list to an interface
a. From the global configuration mode, issue the following commands to assign the priority list to
interface serial 0/1/0.
FC-CPE-1(config)#int s0/1/0
FC-CPE-1(config-if)#priority-group 1
b. Confirm the priority list configuration. From the privileged EXEC mode, issue the show runningconfig
command.
Which statements in the configuration show that the priority list has been configured and applied
correctly?
interface Serial0/1/0
ip address 10.10.0.2 255.255.255.252
priority-group 1
priority-list 1 protocol http high
priority-list 1 protocol ip normal tcp ftp
priority-list 1 protocol ip medium tcp telnet
c. Confirm that issuing the show queueing priority command from the privileged EXEC mode
produces the following output:
FC-CPE-1#show queueing priority
Current DLCI priority queue configuration:
Current priority queue configuration:
List Queue Args
1 high protocol http
1 normal protocol ip tcp port ftp
1 medium protocol ip tcp port telnet
Step 5: Examine the priority queues operation
a. On Host1, launch a web browser and enter the URL http://172.17.1.1 to access the web
services configured on the server.
b. Use FTP to download a file. On Host1, launch a new web browser window and enter the URL
ftp://172.17.1.1, or from the command line issue ftp 172.17.1.1
c. Download a large file from the server; for example, the Thunderbird setup program file.
d. From the privileged EXEC mode, issue the following command:
FC-CPE-1#show queueing interface s0/1/0
Output similar to this should be displayed:
Interface Serial0/1/0 queueing strategy: priority
Output queue utilization (queue/count)
high/94 medium/0 normal/106759 low/0
Note the packet count for each queue:
High
Medium
Normal
Low
e. Initiate a Telnet session from R2 to R1 and issue some show commands on R1.
f. Close the Telnet session.
g. Issue the following command from the R2 privileged EXEC mode:
FC-CPE-1#show queueing interface s0/1/0
Note the packet count for each queue:
High
Medium
Normal
Low
What is the significant difference when compared to the previous output form this command in
Step 5d?
Antrian Menengah sekarang memiliki jumlah paket, ini adalah prioritas yang ditugaskan untuk paket Telnet.
Step 6: Determine the priority queue requirements for the case study
a. Using the FilmCompany case study, what would you expect the priority queue requirements to be?
b. Discuss and compare your priorities with other students.
c. Amend your priority list statements to include traffic associated with the proposed network upgrade.
Step 7: Clean up
Erase the configurations and reload the routers and switches. Disconnect and store the cabling. For PC hosts
that are normally connected to other networks (such as the school LAN or to the Internet), reconnect the
appropriate cabling and restore the TCP/IP settings.
Challenge
The following privileged EXEC command displays the contents of packets inside a queue for a particular
interface:
show queue interface-type interface-number
However, in this lab, it is not likely that sufficient data traffic was generated at one time for the interface
queues to hold packets long enough to be inspected. Discuss how a network has to be load tested to ensure that all traffic priorities are met.
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