Lab 1. QOS - Match IP Precedence

QOS is my weakness I guess :( Maybe because I never do all labs. So let’s study QoS…

For more summary about QoS please refer to http://pursuingmydestiny.blogspot.com/2011/12/qos-summary.html.

What is IP Precedence??? Please have a look again my QoS summary that may help you.

Now let’s do lab to match IP Precedence…

R1#

interface Loopback0

 ip address 1.1.1.1 255.255.255.255

!

interface FastEthernet0/0

 ip address 12.12.12.1 255.255.255.0

R2#

interface Loopback0

 ip address 2.2.2.2 255.255.255.255

!

interface FastEthernet0/0

 ip address 12.12.12.2 255.255.255.0

As you know, there are 3 step in creating QoS using MQC:

1. Configure class-map
2. Configure policy-map
3. Then assign the QoS in interface by using service-policy

Let’s create class-map for classification:

R1#

class-map match-all QOS7

 match ip precedence 7

class-map match-all QOS6

 match ip precedence 6

class-map match-all QOS5

 match ip precedence 5

class-map match-all QOS4

 match ip precedence 4

class-map match-all QOS3

 match ip precedence 3

class-map match-all QOS2

 match ip precedence 2

class-map match-all QOS1

 match ip precedence 1

class-map match-all QOS0

 match ip precedence 0

Then let’s make policy

R1#

policy-map EXCERCISE

 class QOS0

 class QOS1

 class QOS2

 class QOS3

 class QOS4

 class QOS5

 class QOS6

 class QOS7

After that let’s assign the policy to the interface

R1#

interface FastEthernet0/0

service-policy input EXCERCISE

IP Precedence use 8 bit but we use only the first 3 bits of IP TOS field

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Note -> IP Precedence begin from 5^th bit

Here the mapping from binary to decimal:

Level	Precedence	Binary	Decimal	TOS Level
0	Routine	20	0	0-31
1	Priority	25	32	32-63
2	Immediate	26	64	64-95
3	Flash	26+25	96	96-127
4	Flash override	27	128	128-159
5	Critical	27+25	160	160-191
6	Internetwork control	27+26	192	192-223
7	Network control	27+26+26	224	224-255

Now let’s do test the QoS using ping extended by setting Type of service (TOS).

R2#ping

Protocol [ip]:

Target IP address: 12.12.12.1

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]: y

Source address or interface:

Type of service [0]: 165

Set DF bit in IP header? [no]:

Validate reply data? [no]:

Data pattern [0xABCD]:

Loose, Strict, Record, Timestamp, Verbose[none]:

Sweep range of sizes [n]:

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 12.12.12.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 16/30/48 ms

Based on diagram it should be in IP Precedence critical (QOS5). Let’s verify the policy-map in interface fa0/0.

R1(config)#do sh policy-map int f0/0

 FastEthernet0/0

  Service-policy input: EXCERCISE

    Class-map: QOS0 (match-all)

      0 packets, 0 bytes

      5 minute offered rate 0 bps

      Match: ip precedence 0

    Class-map: QOS1 (match-all)

      0 packets, 0 bytes

      5 minute offered rate 0 bps

      Match: ip precedence 1

    Class-map: QOS2 (match-all)

      0 packets, 0 bytes

      5 minute offered rate 0 bps

      Match: ip precedence 2

    Class-map: QOS3 (match-all)

      0 packets, 0 bytes

      5 minute offered rate 0 bps

      Match: ip precedence 3

    Class-map: QOS4 (match-all)

      0 packets, 0 bytes

      5 minute offered rate 0 bps

      Match: ip precedence 4

    Class-map: QOS5 (match-all)

      5 packets, 570 bytes

      5 minute offered rate 0 bps

      Match: ip precedence 5

    Class-map: QOS6 (match-all)

      829 packets, 61362 bytes

      5 minute offered rate 0 bps

      Match: ip precedence 6

    Class-map: QOS7 (match-all)

      0 packets, 0 bytes

      5 minute offered rate 0 bps

      Match: ip precedence 7

    Class-map: class-default (match-any)

      0 packets, 0 bytes

      5 minute offered rate 0 bps, drop rate 0 bps

      Match: any