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SIP trunk with dynamic IP address

hoanghiep
Level 1
Level 1

Hello,

A customer of mine has a SIP trunk connecting their PBX to Telco (Japan NTT). As they are migrating telephony to Cisco CUCM, we are putting a CUBE to connect Cisco IPT to Telco.

However, after consulting with customer, we learned that:

- PBX ip address (the interface connected to NTT) is dynamic, provided by their DHCP.

- SIP server IP address is unknown, and I guess, it should be provided in some options in DHCP.

I searched internet and found a document from Cisco: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube_sip/configuration/xe-3s/cube-sip-xe-3s-book/voi-sip-param-dhcp.html

I tried to simulate the same in my lab but not able to have a working one, not sure if issue is at CUBE side or at simulated-Telco-side.

Do anyone have experience with this before? Any suggestion for me?

Thank you very much,

hoanghiep

8 Replies 8

Tagir Temirgaliyev
Spotlight
Spotlight

1. even PBX ip address  is dynamic, provided by their DHCP it can be statically maped. so it will be the same all the time.

2. you can use loopback IP address. as a SIP address. for both signaling and RTP

3. NTT SIP server IP address is unknown ? ask NTT

Hello Tagir,

I like to follow the easy way as well. but I think there should be some good reasons that dynamic SIP information provided in DHCP is recorded in some RFC. And who knows, maybe the new way will be standard in future?

In the Cisco link in my question, DHCP option 120 and DHCP option 125 are mentioned, they are for SIP server information, RFC3925 and RFC3361 are for these options.

So again, my question is not about the best way to deploy the SIP trunk (which I still think static IP is still the most suitable for now), but how to do it in a new way (with dynamic SIP information provided via DHCP).

Thanks,

hoanghiep.

Ayodeji Okanlawon
VIP Alumni
VIP Alumni

What are you trying to simulate? CUBE to have DHCP? You shouldn't be doing that. It not advisable. The fact that the customer had this in place doesn't mean it's a good practice and this is your opportunity to address it.

Please rate all useful posts

Hello Ayodeji,

I am not trying DHCP on CUBE.

I am trying to use dynamic IP address on CUBE.

Thanks,

hoanghiep

Driss Hadi
Level 1
Level 1

Hi Hoanghiep , 

i'm having the same problem to set up SIP trunk , NTT Japan they mentioned i need to use DHCP to set up a SIP trunk . i configured a DHCP in my CUBE but i'm getting 404 not found . 

if you can assist please on this 

thank you very much .

Hi @Driss Hadi: What do they exactly mean "use DHCP to set up a SIP trunk"?
Thinking out loud "what has DHCP to do with SIP trunk in the first place"?

Which info about the SIP trunk itself did you get from the provider?
Something like username / password / SIP Proxy address / realm / ...?

@b.winter 

Thank you for you for your prompt replay , NTT communication didn't disclose any information they said just use DHCP to setup your SIP trunk .

i used this document :  http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube_sip/configuration/xe-3s/cube-sip-xe-3s-book/voi-sip-param-dhcp.html without any success .

 

But then, your CUBE needs to be connected to an NTT connection, where your router can reach any DHCP server from NTT. This DHCP server from NTT then needs to provide your CUBE with not only an IP address, but also with the options mentioned in the link.
Similar to the figure 2 in the link you've provided.

But all this info needs to come from the provider, nobody else can give you that info (without you being lucky and someone from the community already had this problem too and reads this thread).

If there are some errors or needing help with config, that's where the forum can help you, but all the info about the SIP trunk needs to come from the provider. Unfortunately as that ':/'

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