Hi,

We’ve been doing some experiments to understand how “slow clients” (ie. user 
agents on slow connections) can affect the response times in ATS hierarchies.

[cid:[email protected]]

Keeping it simple for starters. Everything here is about a CACHE MISS. All 
networks are assumed perfect, except for the network towards the client. All 
caches are ATS 9.2.x.

We find that a client on a slow connection, requesting a file (a few MB), will 
take TIME E to receive that file. That time is dependent on the bandwidth of 
their “slow connection”.   That time is correctly reflected in the client 
response time in the ATS log of the Edge Cache.

We see that TIME E becomes a driver of:

  *   TIME M, the time it took to receive that content from the Mid-Tier Cache, 
and also
  *   TIME O, the time, reported at the Mid-Tier, it took to receive the object 
from the Origin.

When this happens, it can be misinterpreted as a slow Origin connection, but 
the timings are actually being dictated by the slow connection to the client.

Could someone point me to a document that explains the network stack of ATS, 
and could help me understand how these “cache miss” chains are handled 
internally?

I’d also like to understand how configuration of any internal buffers could 
reduce the time it takes to bring objects into the Mid-Tier cache. I appreciate 
that may come with other headaches around memory, and maybe this is all 
operating exactly as it should? Any insight would be appreciated.

Many thanks,

Nick

Nick Dunkin
Director, Software Architecture
Manager – Architecture and New Product Introduction
o:  +1 678.258.4071<tel:+16782584071>
e: [email protected]<mailto:[email protected]>

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