Trying to run SNMP1.c on a RCM4000. When I try to hit the RCM with
snmpwalk, I see "SNMP: unknown community '' " and "SNMP: bad
initial squence" in the debug window when I have VERBOSE output
enabled. I'm using SNMPWALK on a windows XP machine and use the
following command "snmpwalk -v 1 -c public 10.5.2.8"

It doesn't matter what I put in for the -c option... I tried public,
private, etc... I always get the unknown community ''

Any suggestions?
Thanks,
-James

------------------------------------



(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )

Hi All,

I will have lines of Rabbit based, ethernet enabled controllers installed in production, and a star topology for ehternet will make my life harder. So, my initial guess is to use a 3 port hub/switch (1 port for uplink, 1 port for Rabbit, 1 port for downlink) on every device to daisy chain the ethernet.

Can someone help me with the folollowing questions:
1. Is it at all possible to daisy chain ethernet? If yes then, what will be a quick and easy way of doing this. Is there a limit of how many devices can be daisy chained on a single line this way?
2. How can I integrate a hub/switch with my device? Is there any off the shelf circuit/IC that I can simply put on my PCB to make it happen?

Thanks in advance for all your help.
Arman



(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )

--- In r...@yahoogroups.com, Arman Rashid wrote:
>
> Hi All,
>
> I will have lines of Rabbit based, ethernet enabled controllers
installed in production, and a star topology for ehternet will make my
life harder. So, my initial guess is to use a 3 port hub/switch (1
port for uplink, 1 port for Rabbit, 1 port for downlink) on every
device to daisy chain the ethernet.
>
> Can someone help me with the folollowing questions:
> 1. Is it at all possible to daisy chain ethernet? If yes then,
what will be a quick and easy way of doing this. Is there a limit of
how many devices can be daisy chained on a single line this way?
> 2. How can I integrate a hub/switch with my device? Is there any
off the shelf circuit/IC that I can simply put on my PCB to make it
happen?
>
> Thanks in advance for all your help.
> Arman
>

It's certainly possible to daisy chain Ethernet connections, although
by doing so you are certainly adding latency between your endpoint
links. You are basically using each hub as an Ethernet repeater to
extend the 100m limit imposed by the standard.

It sounds like you want to add components on your PCB solution for a
switch, rather than simply using an off-the-shelf device at each
rabbit location. I would recommend against it, as small industrial
switches are so readily available and inexpensive. If you need to
create a single board solution with an integrated repeater, you might
want to look into Broadcom's line of Ethernet switch ICs. The
BCM5325E will probably do what you want; just ignore the extra ports
if you really want only 3 ports available. I would recommend bumping
your ports up to 4, so that you can always plug in a laptop at any
rabbit location for debugging.

~Loren

------------------------------------



(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )

--- In r...@yahoogroups.com, Arman Rashid
wrote:
>
> Hi All,
>
> I will have lines of Rabbit based, ethernet enabled controllers
installed in production, and a star topology for ehternet will make
my life harder. So, my initial guess is to use a 3 port hub/switch (1
port for uplink, 1 port for Rabbit, 1 port for downlink) on every
device to daisy chain the ethernet.
>
> Can someone help me with the folollowing questions:
> 1. Is it at all possible to daisy chain ethernet? If yes then,
what will be a quick and easy way of doing this. Is there a limit of
how many devices can be daisy chained on a single line this way?
> 2. How can I integrate a hub/switch with my device? Is there any
off the shelf circuit/IC that I can simply put on my PCB to make it
happen?
>
> Thanks in advance for all your help.
> Arman
>
Howdy,

Ethernet in inherently a star layout network. It can be daisy chained
however it will likely work against you. Why is a star topology so
bad for you? If it's simple the wiring I'd suggest looking into some
of the WiFi adapters available (supply it power, plug it into an
Ethernet device, and it makes your device WiFi emabled), that or of
course switching to a WiFi Rabbit.

Something worth noting I think is that even if the network is wired
in a daisy chain method, the way it works will still be star based.
i.e. you will find no simple method of setting up communications for
passing information left/right N hops. You could do something like
use static addressing and assign an IP based on physical location but
this can get messy if controllers are to be added/removed later on.

Cheers,
Dave
------------------------------------



(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )

Ethernet can run on several different physical interfaces. 10Base-T is
the most widespread, but if you want to "daisy-chain" as many as 30
devices, you should consider 10Base-2 which utilizes RG58 coax rather
than twisted pair cabling.

You can use an Ethernet media converter to convert the Rabbit's
10Base-T signals to 10Base-2 (Thin-net coax). The converters cost
sub-$100 each. You would then run RG58 coax in a bus fashion (with a
Tee for each device). The drawback with this approach is that both end
sof the coax run must be terminated with a 50ohm BNC terminator, and
it's possible to cripple the entire network if you break the coax
line. You'll also need a coax cable crimper to make your own Ethernet
cables.

Google "10base-2" and "10base-2 to 10base-t converter" to find out
more about "thin net". Before the prices of Ethernet switches and hubs
came down significantly and made 10Base-T more affordable (back in the
1990's), 10Base-2 was the way to go.

Regards,
--Mike

--- In r...@yahoogroups.com, Arman Rashid wrote:
>
> Hi All,
>
> I will have lines of Rabbit based, ethernet enabled controllers
installed in production, and a star topology for ehternet will make my
life harder. So, my initial guess is to use a 3 port hub/switch (1
port for uplink, 1 port for Rabbit, 1 port for downlink) on every
device to daisy chain the ethernet.
>
> Can someone help me with the folollowing questions:
> 1. Is it at all possible to daisy chain ethernet? If yes then,
what will be a quick and easy way of doing this. Is there a limit of
how many devices can be daisy chained on a single line this way?
> 2. How can I integrate a hub/switch with my device? Is there any
off the shelf circuit/IC that I can simply put on my PCB to make it
happen?
>
> Thanks in advance for all your help.
> Arman
>

------------------------------------



(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )

10base2 equipment is getting harder to find as it is soooo passe.

Is this something where RS-485 may be used more effectively? What kind of datarates are required? RS-485 networks can be daisychained and can use the same unshielded twisted pair cabling and connectors as 10/100baseT Ethernet. It just does not natively speak IP. This does simplify matters if IP addressing and protocol stacks are not required.

just another thought -
73,
kevin
kc6pob

--- On Sun, 6/8/08, Mike <m...@yahoo.com> wrote:
From: Mike <m...@yahoo.com>
Subject: [rabbit-semi] Re: Daisy chaining ethernet with Rabbit
To: r...@yahoogroups.com
Date: Sunday, June 8, 2008, 11:40 AM

Ethernet can run on several different physical interfaces. 10Base-T is

the most widespread, but if you want to "daisy-chain" as many as 30

devices, you should consider 10Base-2 which utilizes RG58 coax rather

than twisted pair cabling.

You can use an Ethernet media converter to convert the Rabbit's

10Base-T signals to 10Base-2 (Thin-net coax). The converters cost

sub-$100 each. You would then run RG58 coax in a bus fashion (with a

Tee for each device). The drawback with this approach is that both end

sof the coax run must be terminated with a 50ohm BNC terminator, and

it's possible to cripple the entire network if you break the coax

line. You'll also need a coax cable crimper to make your own Ethernet

cables.

Google "10base-2" and "10base-2 to 10base-t converter" to find out

more about "thin net". Before the prices of Ethernet switches and hubs

came down significantly and made 10Base-T more affordable (back in the

1990's), 10Base-2 was the way to go.

Regards,

--Mike

--- In rabbit-semi@ yahoogroups. com, Arman Rashid <Arman1010@. ..> wrote:

>

> Hi All,

>

> I will have lines of Rabbit based, ethernet enabled controllers

installed in production, and a star topology for ehternet will make my

life harder. So, my initial guess is to use a 3 port hub/switch (1

port for uplink, 1 port for Rabbit, 1 port for downlink) on every

device to daisy chain the ethernet.

>

> Can someone help me with the folollowing questions:

> 1. Is it at all possible to daisy chain ethernet? If yes then,

what will be a quick and easy way of doing this. Is there a limit of

how many devices can be daisy chained on a single line this way?

> 2. How can I integrate a hub/switch with my device? Is there any

off the shelf circuit/IC that I can simply put on my PCB to make it

happen?

>

> Thanks in advance for all your help.

> Arman

>



(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )

--- In r...@yahoogroups.com, "Mike" wrote:



> Google "10base-2" and "10base-2 to 10base-t converter" to find out
> more about "thin net". Before the prices of Ethernet switches and hubs
> came down significantly and made 10Base-T more affordable (back in the
> 1990's), 10Base-2 was the way to go.

It's one reason the early 1990's DOS (and later Win 3.1) networking
product Lantastic became so popular because it was affordable to many
companies (and even homes). IIRC they released a 3 or 5 node network
for just under $500, and maybe this was even in the very late 1980's.

Bill
------------------------------------



(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )

Are you compiling the sample prob. that comes with DC?

If you turn on debug and verbose you should get a printout on stdout from DC
as it creates all the OIDs internally, from a previous post it doesn't
appear that DC
will show you the communities that each OID belong to:
http://ssminnow.maesoft.net/SNMPHELP/
Dan...
On Thu, Jun 5, 2008 at 8:56 PM, jkingeek wrote:

> Trying to run SNMP1.c on a RCM4000. When I try to hit the RCM with
> snmpwalk, I see "SNMP: unknown community '' " and "SNMP: bad
> initial squence" in the debug window when I have VERBOSE output
> enabled. I'm using SNMPWALK on a windows XP machine and use the
> following command "snmpwalk -v 1 -c public 10.5.2.8"
>
> It doesn't matter what I put in for the -c option... I tried public,
> private, etc... I always get the unknown community ''
>
> Any suggestions?
> Thanks,
> -James
>
>
>



(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )