Comments:
Name
Transparency breaks authentication
Comment
This is not restricted to transparent proxies. It applies
to all situaions where the client address is changed (NAT).
Name
HTTP metadata must precede content body
Comment
HTTP/1.1 already includes support for this in its
"chunked transfer encoding". It is a transfer encoding
which does not depend on a known content length, and
allows for additional headers to be computed after the
entity is transmitted. (RFC 2616, sections 3.6.1 and
14.40)
Name
Most entries related to ICP
Comment
I think the general consensus on ICP for the last 1 1/2
year (at least) is that has a very limited application.
It does not scale or handle network or server congestion
very well. It is suitable for use on a LAN between closely
related caches, but not in a WAN environment.
Name
Cannot specify multiple URIs for replicated resources
Comment
See URN and related RFCs (specifically RFC2483). No need
to reinvent things, only to get them accepted. The use of
URN resolution is partially supported by Squid.
Another known problem:
Name
Cache meshes can break HTTP serialization of content
Classification
architecture, protocol
Description
A cache mesh where a request may travel different paths
depending on the sate of the mesh and associated caches
can break HTTP content serialization, possibly causing
the end user to receive older content than seen on an
earlier request where the request traveled another path
in the mesh.
Significance
medium
Implications
Can cause end user confusion. May in some situations
(sibling cache hit, object has changed state from
cachable to uncachable) be close to impossible to get
the caches properly updated with the new content.
Indications
Older content is unexpectely returned from a cache mesh
after some time.
Solutions(s)
Work with cache wendors and researchers to find a
suitable protocol for maintaining cache relations and
object state in a cache mesh.
Workaround
When designing a cache hierarchy/mesh, make sure that
for each end-user,URL combination there is only one
single path in the mesh during normal operation.
Contact
hno@hem.passagen.se (Henrik Nordstrom)
-- Henrik Nordstrom Spare time Squid hacker
This archive was generated by hypermail 2b29 : Thu Nov 18 2004 - 11:21:26 MST