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My
apologies in advanced if the answers are obvious, but I've been so focused on
cabling and physical layer the last couple of weeks, so I'm a bit brain dead to
upper layer stuff.
There
has been some talk about differentiated services and priorities associated with
802.1 and the upper layers. Here are my
questions:
1) If
the network is overprovisioned (available bandwidth >= maximum instantaneous
throughput), then am I correct in assuming that these differentiated services
and priorities operate just fine because the upper layer protocols within the
switches have sufficient bandwidth? Should I also assume that the
available bandwidth is based upon what the end stations (adapters, servers,
etc.) can handle?
2) If
the network is not overprovisioned (either in the switches or adapters), then is
it fair to assume that these differentiated services and priorities will provide
diminishing returns as throughput increases over the available
bandwidth?
I keep
coming back to the statement others have made that 802.1 or the upper layers can
handle this, but I cannot help think that would only be true for an
overprovisioned network. Considering that Ethernet doesn't know in advance
about the provisioning of the network and does not care about which packets it
delays or drops, then it is likely that 802.1 and the upper layers can do all
the priorities or differentiated services that they want but will see
diminishing returns as the load on the network increases.
This
would seem to me like going out and buying a Formula 1 race car to use to
drive to work in Silicon Valley. A lot of money in fuel and equipment only
to sit on 101 during rush hour(s).
Am I
off the mark here?
Thanks,
Brad |