Turbo ACLs

Answered Question
Jan 9th, 2008

Hi,

Can any one help me to understand TURBO ACLs?

I have the fundamental clear about it such as:-

The configured access lists are maintian in a sequencial order and the look up time and CPU recuired is reduced.

But i need to know exactly how it works and which platforms support this function.

TIA...

regards,

shri :)

I have this problem too.
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Correct Answer by adityamanda about 9 years 1 week ago

Basically, Turbo ACLs(also known as Compiled ACLs) takes a std or extended ACL, creates a set of data / lookup tables and compiles them for runtime processing. This reduces the number of CPU operations to find a match, allowing larger ACls to be used without increase in packet latency.

Suppose, Turbo ACL is activated on a router, it takes the std/extended ACL as input, creates tables based on those ACL entries, and compiles the tables to allow an arrayed match. Generally, the result is that a match is achieved in 5 steps, regardless of the size of the ACL.

This also indicates that Turbo ACLs are useful when ACL have more than 5 entries. Normal ACLs with 3-5 entries would outperform Turbo ACLs. But with 300-400 lines , Turbo ACLs would outperform sequentially searched ACLs.

for further details :

http://cco.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dttacl.htm

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Correct Answer
adityamanda Thu, 01/10/2008 - 02:32

Basically, Turbo ACLs(also known as Compiled ACLs) takes a std or extended ACL, creates a set of data / lookup tables and compiles them for runtime processing. This reduces the number of CPU operations to find a match, allowing larger ACls to be used without increase in packet latency.

Suppose, Turbo ACL is activated on a router, it takes the std/extended ACL as input, creates tables based on those ACL entries, and compiles the tables to allow an arrayed match. Generally, the result is that a match is achieved in 5 steps, regardless of the size of the ACL.

This also indicates that Turbo ACLs are useful when ACL have more than 5 entries. Normal ACLs with 3-5 entries would outperform Turbo ACLs. But with 300-400 lines , Turbo ACLs would outperform sequentially searched ACLs.

for further details :

http://cco.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dttacl.htm

shrikar.dange Thu, 01/10/2008 - 02:38

hi aditya,

Thanx a lot for your reply.

It is really very help full to me.

Regards,

shri :)

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