Task 7.3: Policing question

Hello.

Is there a difference between these two class configuration (the second one is the given solution):

1) class over1250
police 2500000

2) class sol
police cir 2500000

Regarding the output, there does not:

Rack1R5#show policy-map interface e0/1
Ethernet0/1

Service-policy output: PM-SMTP
Class-map: over1250 (match-all)
100 packets, 126500 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: packet length min 1251
police:
cir 2500000 bps, bc 78125 bytes
conformed 100 packets, 126500 bytes; actions:
transmit
exceeded 0 packets, 0 bytes; actions:
drop
conformed 0 bps, exceed 0 bps

Class-map: sol (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: none
police:
cir 2500000 bps, bc 78125 bytes conformed 0 packets, 0 bytes; actions:
transmit
exceeded 0 packets, 0 bytes; actions:
drop
conformed 0 bps, exceed 0 bps


Is it correct ?

Comments

  • Richard,

    This seems to be a question asked a lot. Police cir is really for 'dual rate' three color policing.

    Long answer:
    Single rate two color or three color can be specified with just the 'police' command. If you configure a violate action, you're doing a single color three rate policer. (conform, exceed, and violate = 3).

    The violate action in the single rate/three color police is based off of the non-rate specific burst BE you configured.

    Here is where the differences come into play:
    in police *cir*, you can configure a 'pir'. This is the specific rate that is referred to when you configure the violate action.

    If a task asks you to police at a certain rate, and if traffic is above that rate, remark it -- but also, if traffic rises above a second rate, do xyz (something). This would be a situation where you'd use police cir with pir defined.

    You can look at the 12.3/12.4 command reference guides to see this all described.

    Short answer:
    police and police cir would both work for this task, as no second rate is needed nor is a violate action needed. You'll achieve the same result.
  • I have Q regarding printout from SG:

    solution:

     Quote:

    R5:
    class-map match-all ABOVE_1250_BYTES
    match packet length min 1251


    verification shows:
     Quote:

    Rack1R5#show policy-map interface e0/1
    Ethernet0/1
    Service-policy output: QoS

    Class-map: ABOVE_1250_BYTES (match-all)
    0 packets, 0 bytes
    5 minute offered rate 0 bps, drop rate 0 bps
    Match: packet length min 1250
    police:cir 2500000 bps, bc 78125 bytes
    conformed 0 packets, 0 bytes; actions: transmit
    exceeded 0 packets, 0 bytes; actions:drop
    conformed 0 bps, exceed 0 bps


    I'm scratching my skull...
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