OA&M port discussion

[ramblingrebel]

I had an outage on a system i just deployed in early september
i had someone who might want to remain nameless provide an assist
one of the issues that cropped up while scrambling was something i do with a bcm that he disagrees with
i have 5 subnets running in my home
i do this so when people come to visit and connect to my wired or wired lan (or all my dumb smart tvs and IOS stuff) never sees my work network or office network
1 is reserved for a wee lab i have with tons of network gear and 6 different call servers (two of them is abcm50 and bcm400)
this subnet is the subnet of the OA&M port
now i WILL admit, i do not recall ever having the bcm's plugged into the network switch while they booted up
i think i'd wait until they booted up before i plugged them into the switch
(and i'm not talking about the customer LAN port just to be clear)
in this case, the replacement bcm50 this fellow sent me, i plugged in and then booted up.....
the bcm stalled (1green light and 1 red light)
it wasn't until i unplugged from the network switch did it come up
once up i could plug into the OAM port through the network switch and do my restore
now my core competency's are a Centrex SME and for the last 15 years been doing carrier/ ISP and enterprise networking, routing and security
but i have had a cis and bcm and or norstar in my home for the the last 30 years
and i have about 10 bcmcustomers i support, but i am by no means a bcm expert
this stalling on boot up because its plugged into a network switch makes absolutely no sense to me.
any bcm gurus explain technically why this happens? The fellow said "its meant to be plugged directly into"
fair statement but....technically it makes no sense....
and although i have not dug out the install guides, if this were in fact true i would think there should be a full page where "DO NOT PLUG INTO A NETWORK SWITCH- EVER" should be on it
nothing earth shattering, but my brain is stuck on this "squirrel"
insights?
rr

 

[telcodog]

You shouldn't plug that into a working network because that port has the DHCP server enabled on it. Although it has a mask of 1255.255.255.252, it will still respond to dhcp requests.

That being said, if you plug into that network and don't get the 10.10.11.2 address assigned, you can statically assign yourself and probably get to it but in general you shouldn't connect it to a network that already has a dhcp server for it.

You can try modifying the LAN parameters for that port but I have never tried so not sure if it will let you.

 

[ramblingrebel]

telcodog
thanks for the response
and its not really a big deal to me, just a discussion myself and the fellow tech got into yesterday
the easy answer is just not have it plugged into my network when it boots up. I usually plug into customer Lan when doing a new system
this time i just happened to plug it in to the OAM as the laptop on that subnet was right there

i'm not doing any routing between the subnets
so i don't see how any dhcp requests would reach that subnet
and wouldn't have thought a statically assigned OA&M ip port address would put out a dhcp request?

just something that makes m go HHMMM....
rr

 

[curlycord]

It's ok, I am the nameless fellow (his vendor).

To be clear my angle is when you are troubleshooting always direct connect to OAM.
I did say it was designed to be the techs port for direct connection but I do I also agree with you it makes no sense.
At the same time I was thinking something on your network is not agreeing with the BCM so I did a couple tests this morning.

Although not an exact duplication of your network this is a test I did perform on a spare BCM:
OAM is 10.10.11.1 - 255.255.255.252 - Normally direct connected to my PC's second LAN port
LAN is 192.168.1.2 - 255.255.255.0 - Connect to my office network
I powered down
Unplugged my OAM cable
Moved my LAN cable over to the OAM and booted up
So now we will have a BCM's OAM 10.10.11.1 - 255.255.255.252 trying to connect on a Network 192.168.1.XXX
For a minute or 2
Amber
Green

Then endlessly
Red
Flashing Green

But!
The phones do come up

So now part of my thinking is you assumed the BCM did not boot up because your set did not work.
Even after connecting direct to OAM and rebooting there is still the assumption it did not boot up.
Then we discovered the mod line cord was defective and why the set did not come up but after replacing it the phone works, BCM ok.

So my thinking is the BCM originally did come up but there is a network issue hence the Red with Flashing Green.
There is nothing in the guide about this particular LED status but will take this as a Network error be it on the BCM or your Network.

Side note, moving the LAN patch cord from OAM back to the LAN port and then plugging PC patch cord back into the OAM did not solve the LED's status.
I was not able to connect to OAM but I was able to connect to the LAN.
There was no alarms listed.
Rebooting fixed being able to connect to OAM again and restored LED's to Green Green

So on my truck backup BCM try again to boot up while connected to OAM on your network just to make sure the phone does in deed work when booting with OAM connected and note the LED status to see if it matched my test.




________________________________________

=----(((((((((()----=

http://www.curlycord.com

Toronto, Canada

Add me to LinkedIN

 

[exsmogger]

My experience with booting BCM50s or BCM450s is to never connect to the OAM port until it's completely finished. It causes nothing but grief on the network.

Brian Cox
Georgia Telephone

http://Georgia-Telephone.com

http://www.linkedin.com/in/briancox1952

 

[ramblingrebel]

so i have always, for 25 years now, had at least 3 separate subnets in my house/ lab
I'm running 5 right now
no routing between them
one day i'll play with VLAN's again, or not
one is reserved solely for systems management
on that one i have had almost everything i've ever touched attached to it (with the exception of my old centrex/ ISDN switch)

PP7k, CS1k's, CVX's, baystacks of every flavour, Mitels, Aastra's, a plethora of cisco's call servers, DSLAM's, IP Office
in my panic mode i plugged into the OAM port on bcm and started powering up while i got my management Laptop all setup

thats when the panic got worse. I can't believe plugging into a network STALLS boot up
worst case i've seen is it grabs up another devices address (but on my management LAN i only plug in static addressed devices)

i'm still stunned the phone and silver satin i was JUST talking to curlycord on had the silver satin go defective in the 10 feet i walked with it
i should have had my surveillance camera's on and youtube the confused looks i had going on

lesson learned i guess, as exsmogger states, just leave it off until bcm comes up (like i usually do)

now where's Jim Bean hen you need him

rr