| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 908.1 | Yes, if I understand your question correctly | LEVERS::PAGLIARO | Rich Pagliaro, Hub Products Group | Mon Apr 25 1994 16:05 | 55 |
| I'm not sure I fully understand your question. I think the short
answer to your question is yes, the DECrepeater 900FP and DECrepeater
90FS support redundant "ring" topologies. But I'd rather not call them
"rings", for clarity's sake.
Both the DECrepeater 900FP and the DECrepeater 90FS support redundant
link topologies in which primary and secondary redundant responder
ports reside on separate modules. These responder ports must, however,
reside on the same LAN. Redundant master ports must reside on the same
module. An example of such a topology is depicted below.
(redundant hubs in wire center)
+-------------+ +-------------+
| +---+ +---+ | | +---+ +---+ |
| |FMM| |TMM| | 10BaseT | |TMM| |FMM| |
Single Redundant | | O | | []==================[]| | O | |
Responder Port | | O | | | | | | | | O | |
########O | | | | | | | | O | |
# | | O | | | | | | | | O | | Single Redundant
# | | O | | | | | | | | O | | Responder Port
# | | O | | | | | | | | O########
# | | O | | | | | | | | O | | #
# | | O | | | | | | | | O | | #
# | | O | | | | | | | | O | | #
# | | O | | | | | | | | O | | #
# | | O | | | | | | | | O | | #
# | | O | | | | | | | | O | | #
# | +---+ +---+ | | +---+ +---+ | #
# +-------------+ +-------------+ #
# #
# Fiber Fiber #
# Primary Link Secondary Link #
# #
# #
# +---+ #
# |FMI| #
# | | #
########################O | Redundant Master #
| | Port Pair #
| O########################
+---+
(in workgroup)
Please let me know if this is not the type of "ring" you were talking
about.
The DECrepeater 900FP Installation and Configuration Manual
(EK-DEFMM-IN) covers this and other redudant configurations in detail.
I assume that the DECrepeater 90FS Installation and Configuration
Manual covers these topics also.
Regards,
Rich
|
| 908.2 | I'll try to clarify my question | BIKINI::KRAUSE | CSC Network Management/Hubs | Wed Apr 27 1994 08:30 | 32 |
| No, this is not what I meant with "fiber ring". The configuration
described in .-1 is explained in the manual. I'll try to draw a picture
to clarify my question:
+---+ +---+
|FMI| |FMI|
| | | |
| O###############################################O |
| | | |
| O | | O |
+-#-+ +-#-+
# +---+ #
# |FMI| #
# | | #
########################O | #
| | #
| O########################
+---+
##### means fiber link
One of the three fiber links would normally be inactive (redundant) to
prevent a loop. But when one of the active links breaks, the redundant
link should become active to re-establish connectivity.
Is this configuration possible?
This is a very common customer question here, because many currently use
Hirschmann equipment and Hirschmann provides exactly this type of ring
redundancy.
*Robert
|
| 908.3 | Do I understand you correctly now? | LEVERS::PAGLIARO | Rich Pagliaro, Hub Products Group | Wed Apr 27 1994 10:25 | 81 |
| Unfortunately, I am still not sure I understand fully what you mean by
"fiber ring". I can interpret the diagram in .2 in one of two ways.
My first interpretation of .2 is as follows:
+---+ +---+
|FMI| (This link is always active) |FMI|
| |<------Non-redundant repeater ports------->| |
| O###############################################O |
| | | |
| O |<----Single Redundant Responder Ports----->| O |
+-#-+ +-#-+
# +---+ #
# |FMI| #
# Primary Link | | #
########################O | #
(This link may be | | Secondary Link #
active, standby, | O########################
or broken) +---+ (This link may be
Redundant Master Port Pair active, standby, or
broken)
In this case, each "O" above depicts one full fiber repeater port (i.e.
both transmitter and receiver). Each "#" above depicts a
transmit/receive fiber pair for a given link.
This configuration is essentially equivalent to the diagram in .1 and
is supported by both the DECrepeater 90FS (DEFMI) and the DECrepeater
900FP (DEFMM).
I can also interpret the diagram in .2 as follows:
+---+ +---+
|FMI| |FMI|
Port 1 | | ---> | | Port 1
Transmitter | O#####################################O | Receiver
| | | |
Port 1 | O | | O | Port 1
Receiver +-#-+ +-#-+ Transmitter
# +---+ #
# Port 1 |FMI| #
# Transmitter | | #
###################O | #
<--- | | <--- #
| O###################
+---+ Port 1
Receiver
In this case each "O" depicts one half of a fiber repeater port (either
a transmitter or a receiver). Each "#" depicts a single fiber.
This configuration is clearly NOT supported by any of Digital's fiber
Ethernet repeaters.
Regards,
Rich
|
| 908.4 | Addendum to .3 | LEVERS::PAGLIARO | Rich Pagliaro, Hub Products Group | Wed Apr 27 1994 10:50 | 66 |
| I can also redraw the first diagram in .3 as follows:
+---+ +---+
|FMM| |FMM|
Redundant | | Primary Link | |Individual
Master | O###############################################O |Redundant
Port Pair | O###############################################O |Responder
| O | Secondary Link | O |Ports
| O | | O |
| O | | O |
| O | | O |
| O | | O |
| O | | O |
| O | | O |
| O | | O |
| O | | O |
| O |<----Single Redundant Responder Ports----->| O |
+-#-+ +-#-+
# +---+ #
# |FMI| #
# Primary Link | | #
########################O | #
(This link may be | | Secondary Link #
active, standby, | O########################
or broken) +---+ (This link may be
Redundant Master Port Pair active, standby, or
broken)
In this case, each "O" above depicts one full fiber repeater port (i.e.
both transmitter and receiver). Each "#" above depicts a
transmit/receive fiber pair for a given link.
The configuration depicted in the first diagram in .3 not recover
from a fault on the link between the non-redundant DEFMI repeater
ports (depending upon the full configuration and the presence of faults
on any other links). The diagram above provides a extra level of
protection. However the DEFMI cannot support this configuration since
it does not have enough ports.
Regards,
Rich
|
| 908.5 | Second attempt for clarification | BIKINI::KRAUSE | CSC Network Management/Hubs | Wed Apr 27 1994 12:21 | 32 |
| Now we're getting together. Your first interpretation is very close.
What I really want is all three links being equal, with normally (any)
two active and the third in standby. To complete the picture: The
repeaters are of course each connected to a LAN segment with stations,
etc. The configuration should be able to tolerate a break in any *one*
link without loosing connectivity between the segments.
+---+ +---+
|FMI| (This link active, standby or broken) |FMI|
| |<----------------------------------------->| |
| O###############################################O |
| | | |
| O | | O |
+-#-+ +-#-+
# +---+ #
# |FMI| #
# | | #
########################O | #
(This link may be | | #
active, standby, | O########################
or broken) +---+ (This link may be
active, standby, or
broken)
In this case, each "O" above depicts one full fiber repeater port (i.e.
both transmitter and receiver). Each "#" above depicts a
transmit/receive fiber pair for a given link.
This concept should be expandable to more repeaters/links, e.g. four
repeaters with four links between them forming a ring.
*Robert
|
| 908.6 | No | LEVERS::PAGLIARO | Rich Pagliaro, Hub Products Group | Wed Apr 27 1994 14:55 | 16 |
| Now that I understand what you were asking, the answer to your question
is no. The DECrepeater 90FS and DECrepeater 900FP cannot support the
ring topologies you described.
I'm not familiar with the implementation or performance of the competitor's
solution. It almost implies some sort of "spanning tree" protocol
between the repeaters. This type of data-link layer fault detection
typically takes on the order of seconds to respond to a fault. Do you
have any performance information on the competitor's product?
Regards,
Rich
|