Cisco SPA504G config SIP don't ringing

[scotop]

Hello,

I use he Cisco IP Phone 303 for our call center with Vocalcom and it's work good.

but this week we baught a SPA 504G and it's not work..

it's ok in the brekeke and ok in the List of Station in Vocalcom but when the soft want to transmitt the call to the SPA504G, the phone not ringing and the Vocalcom put itself in "Pause"

I did not baught the Phone at Vocalcom so their support don't help me..(but we pay a lot of money to have support at vocalcom!!!)

so maybe someone can help me to finish the configuration SIP..

The phone works good (IP 303):

I put the same parameters in the 504G : Proxy IP, UserId and DisplayName but the phone don't ringing (SPA504G) :(

config SIP : 

page 1 : 

page 2 :

if you have a idea..

thank you very much

Raffy

[Dan Lukes]

Assuming you are running the same firmware version, the SPA303 and SPA504G is the same device. Assuming identical configuration of both devices, the behavior must be same.

Thus you are either running different firmware or different configuration.

I assume the second - SPA504G is not configured the same way. It's not only about three options you mentioned. Log in as administrator, switch to advanced view - and all options must be same on both devices.

[Dan Lukes · Accepted solution]

... by the way - I assume you *replaced* SPA303 by SPA504G. If you are adding second phone, then the configuration will not be exactly same. At least SIP credentials will be different. Also, NAT (if there's any) needs to be taken into consideration when second phone added.

[scotop]

Thank's for your idea.. i will try it.

maybe i must to upload an old firmware to the 504G ? is it possible ? maybe the 50G denied when i will try upload..?

[Dan Lukes]

Downgrade is "unsupported procedure" unless advised by technical support.

Downgrade can brick the phone, especially if there's configured that's unsupported on older firmware. To minimize risk, downgrade phone in factory default configuration.

One "Big step" downgrade is more dangerous than "decremental" downgrade (serie of several "small step" downgrades, reset to factory default before each step). If release notes order incremental upgrade thru specific firmware version, the same firmware must not be missed during downgrade.

Some so new hardware revisions can't take so old firmware at all (compatibility table is part of release notes of particular firmware).

But I'm almost sure your issue is not caused by firmware version. Thus I don't recommend downgrade to you.

Note we decided to use "try & wish" method of issue solution. We may consider to use "analyze cause & solve" method instead, but it require data to analyze - e.g. full syslog&debug as well as captured SIP packets related to the broken call.

[scotop]

it's very stange, the only difference between the  telephone is that the 504G don't find the dhcp server when it start.. I have to put it a IP-fixed option.. it's the only differnce..

[Dan Lukes]

don't find the dhcp server when it start.

I have hundreds of SPA504G deployed in various company's network in seven countries around and all of them use DHCP with no issue you mentioned. It doesn't mean the issue you are facing doesn't exists, of course.

We need to narrow the cause. The issue may be caused by

1. DHCP request is not send by SPA504G
2. DHCP request is not delivered to DHCP server despite sent
3. DHCP server has rejected request or didn't responded to it at all despite delivered
4. DHCP response has not been delivered to phone
5. phone drops DHCP response with no effect despite delivered

I recommend you to start in the middle, e.g. [3] - verify the DHCP server is receiving DHCP requests and is responding them. If it receives no requests, continue with 1,2; if it respond them properly continue with 4,5. If it doesn't respond or reject requests despite received, it's guilty.

I'm curious to know the final cause. SPA3xx and SPA5xx are almost identical thus I have no idea why SPA3xx should work here with no issue, but SPA5xx have issue.

Of course, I assume your DHCP server is configured to provide IP address to unknown devices, or you has added MAC address of phone in question to list of approved/known devices already.