| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 1818.1 | | NETCAD::SLAWRENCE | | Tue Dec 27 1994 09:55 | 4 |
|
The DECconcentrator isn't a switch; there are no comparable numbers -
the latency is effectively zero.
|
| 1818.2 | what about Bridges, Term Servers ? | ANNECY::MAIGRET_Y | | Wed Dec 28 1994 03:50 | 12 |
| Hi,
Thanks for your reply, but I need a clarification.
Can I considere that the "latency values" are known only for the switch
family, and are zero for all others DECHUB equipements like bridges,
Terminal servers, Concentrators etc.
Regards,
Yves
|
| 1818.3 | | NETCAD::SLAWRENCE | | Wed Dec 28 1994 09:54 | 21 |
|
You need to define what you mean by 'latency' for each type of device;
for a switch, it is typically used to describe the time between the end
of the receipt of a frame on one interface until the start of
transmission on the outgoing interface, or the amount of time added by
the switch over what the packet would take if there were just one
segment without a switch. Bridges are switches - no practical
difference.
Concentrators and Repeaters essentially operate at the bit level (yes,
this is a slight oversimplification) rather than the frame level, so a
latency measurement would be in the time delay for a bit (or a symbol
on FDDI) and is so small that you can treat it as 0 for all purposes
except figuring cable lengths on your network (the repeater hop rules
are a practical expression of this latency, and on FDDI it's built into
the maximum station limit for the ring).
Terminal servers might have many different usefull latency measurements
depending on how they are being used - questions about them are best
posted in the TOOK::TERMINAL_SERVERS conference.
|
| 1818.4 | Latency *applies* to bridges & switches, not to concentrsators | NETCAD::BATTERSBY | | Wed Dec 28 1994 10:02 | 10 |
| The bridges are the switches with their names changed to use the
latest in marketing/selling ploys. The competition started calling
their bridges "switches", (of course some of them are real switches
which don't store-and-forward frames). Our switches do "real"
bridging (store-and-forward), at wire speed, and have very very
competitive latency values. Wiring concentrators do not store and
then forward frames, thus "latency values" do not apply to a
network component such as a concentrator, or a terminal server.
Bob
|
| 1818.5 | Thanks for your anwers | ANNECY::MAIGRET_Y | | Wed Dec 28 1994 10:42 | 0
|