| Title: | DEChub/HUBwatch/PROBEwatch CONFERENCE |
| Notice: | Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7 |
| Moderator: | NETCAD::COLELLA DT |
| Created: | Wed Nov 13 1991 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 4455 |
| Total number of notes: | 16761 |
Hello,
This note about competition between FDDI networks and Ethernet switchs.
We have a customer which had performance problems on an Ethernet
network where we can found centralized in a computer room all big
machines and decentralized on 6 sites with fiber optic all the
workstations, PC and Decserver.
We have proposed a solution with at first step DECHUB 900,DECbridge 900
in central and in some other sites a Decbridge 900 alone in order to give
more throughput to access the central machines. In second step future
(because customer is going to migrate after VAX TO ALPHA) we propose
direct connections to the FDDI networks for the computers.
The problem is that competitors are proposing Ethernet switches (like
Kalpana or SMC ) with direct connections of central VAX's on to the switche
and also optic cards to connect directly to the switch.
I don't know very well these Ethernet switches and it will be useful
for me to have some information in order to give the advantages and
inconvenients of the ethernet switch solution in order to argument our
solution .
Thanks in advance for any help.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 876.2 | Kalpana experience (old, maybe outdated) | NYOS02::HERENDEEN | Tom Herendeen @NYO, 352-2936 | Thu Mar 31 1994 19:04 | 34 |
Christine -
For what it is worth, JP Morgan in NY had a Kalpana Switch in for
evaluation about 18 months ago and sent it back because it forwarded all
invalid packets (runts etc.) because the packet was not verified before
it was shipped out. Morgan has since installed a pair of FDDI back
bones in their main building that they connect all their Ethernets and
Token Rings to (via Cisco routers and DECbridge 620's), and they are in
the process of installing two gigaswitches to minimize congestion on
the FDDI rings. They will be installing a third FDDI ring soon. To
date only three business groups are actually implementing FDDI at the
workstation level (one case was due to a single workstation requiring
52% of an Ethernet's bandwidth, and they had 60 of these ill-behaved
workstations trying to run the application...)
As for performance problems, you may want to look at the locality of
servers to clients. One of the other Morgan sites in NY has been
trying to centralize their servers but they have had enough sense not
to put all the servers on the same segment; by the judicious use of
bridges and routers they are able to isolate traffic while still having
a central computer facility.
I think you are on the right track by proposing the DEChub 900 and
DECbridge 900MX's. If you have TCP/IP on the network, you should look
at routing that protocol, future releases of the 900MX firmware will
support that function; in the interim look at the DECnis or a (shudder)
CISCO router (Don't use CISCO's for bridging however, they don't do all
that good a job). You may also want to route SPX/IPX too, bridges may
not provide sufficient control.
Good luck
Tom Herendeen
NY PSC
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