Why do I see local echo from the WiSP but not the DOIAP?

Digi One IA/IAP
1

Sun Ultra 60 at 192.168.0.14
Win2k box at 192.168.0.20
Digi WiSP at 192.168.0.67
Digi One IAP at 192.168.0.68
Unknown wireless access point.

The Digi One IAP is connected to com1 of the win2k box (Hyperterminal).

The Digi WiSP is connected to com2 of the win2k box (Hyperterminal).

I’m running tcpdump on the Sun, and a custom UDP monitor app on the windows box.

Each Digi is configured to UDP sockets, listening on port 2101 and transmitting to 192.168.0.255 port 2101 (network broadcast). For testing purposes, I’ve set the Digis to fire off a UDP datagram when receiving a carriage return, after 1s of idle input, or when the buffer hits 1k of data.

If I type in the Hyperterminal window connected to the Digi One IAP, I see the typed data appear at the WiSP, the Sun, and the win2k box. If I type in the Hyperterminal window connected to the Digi WiSP, I see the typed data appear at the DOIAP, the Sun, the win2k box, and the WiSP! (It’s not local echo in Hyperterminal–the echo doesn’t show up until I hit the enter key or the 1s timeout expires.

I’m having trouble determining why the WiSP is seeing it’s own transmission while the DOIAP is not. It could be the Digi firmware, or maybe something to do with the wireless connection. I don’t really know how to troubleshoot this any further. (If I could locate a 802.11 capable notebook, I guess I could see if it echos back.)

I can probably modify my higher level protocol to deal with the local echo situation, but it will cause a little bit of loading just from examining and rejecting outgoing local messages.

Another workaround would be to configure UDP sockets to send to every other IP address in the local group, instead of using the network broadcast address. This does prevent the local echo at the WiSP, but I’d like to use the broadcast address as it simplifies configuration.

2

The WiSP and DOIAP are 2 very different platforms, so it could be a firmware ‘default’ issue. WiSP is a Digi “ARM” processor with a ThreadX type RTOS. The DOIAP is a Coldfire with a custom stream-based OS.

I’d first guess there is a setting in the WiSP, I’ll ask around.

3

There are only a few reasons I can think of why you might be seeing such a problem. Either hyper terminal has it’s local echo enabled, you’ve set a bad route in the UDP table (i.e. pointing back to your device), or you have some type of cabling problem.

By default the Wi-SP will not echo back data when it’s setup for UDP sockets.

4

> There are only a few reasons I can think of why you
> might be seeing such a problem. Either hyper terminal
> has it’s local echo enabled, you’ve set a bad route

It’s most certainly not HT local echo–the echo doesn’t appear until the UDP socket tx timeout or the carriage return.

> in the UDP table (i.e. pointing back to your device),
> or you have some type of cabling problem.

All units have the same UDP socket config: 192.168.1.255, the subnet broadcast address.

> By default the Wi-SP will not echo back data when
> it’s setup for UDP sockets.

I’ll power one up, default it, and check again.

5

> I’ll power one up, default it, and check again.

It looks like one WiSP firmware version does echo:

Firmware Version: 1.9.0 (Version 82001220_F5 09/16/2005)
Boot Version: 1.1.1 (release_82001187_A)
POST Version: 1.1.3 (release_82001188_D)

And another does not:

Firmware Version: 2.4.5.1 (Version 82001220_H2 12/20/2006)
Boot Version: 1.1.3 (release_82001187_C)
POST Version: 1.1.3 (release_82001188_E)

If anyone wants to diff my config and find my mistakes, I’ve attached them. (Wow! Those rci commands are pretty verbose. I much prefer the DOIAP backup file format.)

–
newell

6

Haha - but RCI is XML, and isn’t XML the be-all and end-all to save Humanity? (wink) You can tell I’ve been in too many meetings. Funny how such “truisms” develop and self-propagate unchallenged.

You can still use the telnet-style “set” commands but you need to manually discover what they should be. I routinely use those to document the cellular unit as a “diff” or changes from the default. You end up with a text file with a dozen lines or less. For cellular these are especially nice since one is paying for bytes of traffic so use of SSH is cheaper than use of HTTP or HTTPS.

7

> Haha - but RCI is XML, and isn’t XML the be-all and
> end-all to save Humanity? (wink) You can tell I’ve
> been in too many meetings. Funny how such “truisms”
> develop and self-propagate unchallenged.

It’s worse than that–I was clever enough to save the config before deploying the system. However, the RCI/XML output doesn’t appear to include any firmware version info, so I can’t be certain which radios are running the good stuff and which aren’t. (The newer firmware does spit out a bigger config file, but I can’t be sure that there’s not an ‘in-between’ version running in our system.) Grrr.

Is there a channel for gripes^H^H^H^H^H bug reports and product improvement suggestions? The WiSP would be a lot nicer if the activity light worked, if it had reverse polarity protection, it should include the firmware info in the config dump, and (dare I dream?) a signal strength indicator.