How much will the cpu load increase when I apply CAR at C7513?

[Woohyun Chang <whchang () bora net>]

  some WAN interfaces     R1          R2    some WAN interfaces
             -----------C7513      C7513------------
                          |           |
                          |fe         |fe
                        ======switch=======

R2:     C7513
        RSP2
        no VIP card
        cpu load: 18%
        FastEthernet: 
                outbound: 6Mbps
                inbound:  22Mbps
        Cisco IOS 11.1.18CC 
        RED is not available because 11.1.18CC does not provide RED without VIP card.
    
The input queue at the FastEthernet of R2 is insufficent because
there are many inbound packet more than outbound packet into some WAN interfaces at R2.
Therefore, packet drops happens at Fastethernet of R2.

I tried to increase the input queue of the FastEthernet of R2, and
I found that that is useless. So I'll try to apply CAR(committed access rate).

I have two questions.

1. If I apply CAR at FastEthernet of R2 for inbound traffic, 
   how much will cpu load of R2 increase? 
   I hope that the cpu load does not increase very high.
   The condition for the classification of IP traffic will be very simple.

2. Is it possible  that my work applying CAR will fix the packet drops at FastEthernet? 
   Will my work make queue available faster than before?

Regards,

/woohyun chang
whchang () bora net
BORANet Services
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