| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 2374.1 | Physically move them & leave them alone | NETCAD::BATTERSBY | | Mon Jun 12 1995 19:21 | 11 |
| The root bridge by default is always the one with the lowest
Ethernet address. So if he knows what all the Ethernet addresses
of his bridges are, he could physically place the DEWGF-AA with
the highest address in the location desired for the one to be in
backup. If the power in the plant comes on at the same time, there
is plenty of time (30 seconds) while the DEWGF's learn each other
and determine who the root bridge is (and as a result they will
learn where the redundant paths are), and the bridges in the redundant
paths will presumably be the bridges with the highest addresses.
Bob
|
| 2374.2 | | NPSS::MDLYONS | Michael D. Lyons DTN 226-6943 | Tue Jun 13 1995 14:12 | 13 |
| ...note that other vendors may use different default root
priorities. For example, the IEEE spec actually recommends 32768 as
the default. It is always safer to set the root priorities of your
bridges to appropriate values to assure that you get the results you
expect. Be careful when replacing bridges!
Root priority takes precedence over the MAC address, which is used
as the tie-break for equal root priorities.
Also note that the order in which you power on the bridges has no
effect on the outcome of spanning tree. If the priorities and/or MAC
addresses are such that the newly powered on bridge should be the
active path, a spanning tree transition will take place.
|
| 2374.3 | Thanks | VAXRIO::ROLF | Vaporware Design Specialist | Wed Jun 14 1995 15:38 | 8 |
| OK, so that only leaves the physical placement of the boxes, because
that LAN has nothing that could manage the bridges (DECbridge90's).
Actually, the fact that the power up sequence does not change the ultimate
spanning Tree result, makes much more sense.
Thanks again!
Rolf
|
| 2374.4 | Can you Set Priority via MOP on DEWGx ? | MSDOA::REED | John Reed @CBO = Network Services | Thu Jun 15 1995 03:56 | 17 |
| You can manage a DECbridge 90 using any MOP host (such as a VAX, or an
ULTRIX node) by doing an
NCP> connect node via isa-0 phys address 08-00-2b-23-34-56
This will allow you to communicate with the bridge, and do SET and
SHOW commands. I beleive that the spanning tree PRIORITY is factory
set in the Bridge 90 at FF-FF, in the assumption that this bridge is a
"leaf bridge", and therefore not likely to ever be the root if ANY
OTHER bridge type is on the network.
IF you can modify the priority, then you can make the tree behave
precisely as you wish under any circumstance.
Good Luck
JR
|
| 2374.5 | seems to be working | VAXRIO::ROLF | Vaporware Design Specialist | Tue Jun 20 1995 12:53 | 17 |
| We tried to change the priority of a DECbridge90 here in the office,
but NCP won't allow you to do that. You can access every other
parameter, but not the priority, from the looks of it!
Hubwatch however seems to allow you to access the priority, but since
that customer doesn't have HUBwatch, it's really unimportant.
Guess we're stuck with the option of physical placement of the boxes.
Other than that the network is running fine, which made me happy,
because we designed that some 3 years ago when it was still sort of
taboo to have DECbridge90's in sequence....
I havn't heard from the customer lately (no news is good news!), but
will post results here.
Rolf
|
| 2374.6 | | NETCAD::ANIL | | Wed Jun 21 1995 16:32 | 4 |
| Another way to do it is by changing links costs - make them higher
on the bridges you want to have in standby.
Anil
|