About Pre-shared key in PMP 450 family

Hi all,

I'm trying to configure a PMP 450i AP (5.Ghz) but I don't understand one element...if someone can help

me understand this it will be very nice.

"We need to set the pre-shared key on SMs and reboot them first before setting that key on the AP"

This seems very strange to me because if we want to add others SMs should we retry all the process?

(after setting the key on the news SM and rebooting it, we reset the key on the AP which will cut all the current connexions with the current registered SMs)

What is the best process to register another SM with an AP (on which others SMs are connected)  when using "pre-shared key" authentication mode?

an ISP will want to register an SM with a AP dynamically what is the solution in this case?

Best Regards


Where are you reading this from?

All you need to do is set the pre-shared key on the AP once, and then set it on any SM's that connect. Similar to how you'd configure a WiFi AP and client.

You do have to reboot the SM however after setting the key. Pretty much all settings on the SM need a reboot after save in order to take effect.

If you wish to use something more dynamic, you could use an authentication server or RADIUS AAA.

taken from "PMP 450x Configuration and User Guide 15.1.1.pdf" Page7-113 (or 422/820)

this is the text, read the part in bold...may be it is me the problem

AP PreShared Key - The AP/BHM acts as the authentication server to its
SMs/BHS and will make use of a user-configurable pre-shared
authentication key. The operator enters this key on both the AP/BHM and
all SMs/BHS desired to register to that AP/BHM. There is also an option
of leaving the AP/BHM and SMs/BHS at their default setting of using the
“Default Key”. Due to the nature of the authentication operation, if you
want to set a specific authentication key, then you MUST configure the
key on all of the SMs/BHS and reboot them BEFORE enabling the key
and option on the AP/BHM. Otherwise, if you configure the AP/BHM first,
none of the SMs/BHS is able to register

In the context of an AP and SM's that are already using a form of authentication, then yes... that paragraph is correct. You'd need to change the SM's authentication key/method FIRST and then change the AP's in order for the SM's to reconnect.

hm...even in that case I don't see the necessity to change the key on SMs and reboot them first...

I just have to change the key on all devices(AP and SMs) and the reboot them.

I can set the key on the AP first or in the reverse order and thing will work...the order doesn't mater(I think)

PS: Eric Ozrelic thank for your help, very appreciate.



@nar6du14 wrote:

I can set the key on the AP first or in the reverse order and thing will work...the order doesn't mater(I think)

The order does matter, that's why they tell you to do the SM's first. If you saved (but not rebooted) a new key on the AP and SM's, and then rebooted the AP to make the changes effective, then the SM's would no longer be able to connect (even though you've saved the new key, it's still not in effect until after you reboot the SM). That's why they say to set, save, reboot the SM's FIRST and then to do the AP.

This is standard for many radios... you almost always want to apply link breaking changes to the FAR/client side of the connection, and then change the closer/AP/master side last.