On 30-sep-2006, at 16:47, Deguang Le wrote:
This paragraph presents "SHIM6 needs to avoid sending packets
concurrently over multiple path".
However, in RFC 3582 - Goals for IPv6 Site-Multihoming Architectures,
Load sharing is one of the goals of multihoming.
3.1.2. Load Sharing
By multihoming, a site should be able to distribute both inbound and
outbound traffic between multiple transit providers. This goal is
for concurrent use of the multiple transit providers, not just the
usage of one provider over one interval of time and another provider
over a different interval.
Therfore, I would like to know if this sentence "SHIM6 needs to avoid
sending packets concurrently over multiple path" means that SHIM6
doesn't support load sharing?
The text you cite pertains to individual shim contexts. Often, a shim
context will be used for a single TCP session, and it's considered
suboptimal to have packets belonging to the same TCP session travel
through different paths, because this introduces packet reordering
which impedes TCP performance.
However, shim6 still supports load balancing by allowing different
contexts to use different addresses, so that part of the contexts will
generate traffic over one path and part of the contexts over another path.
Note though, that most traffic will be associated with contexts for
which no shim6 address rewriting is active, so load balancing greatly
depends on things outside the scope of shim6, such as information in
the DNS and routing.