MBG used for Teleworker and SIP Trunks [Solved]

[Tech Electronics]

Mitel Gurus,

Alright, here is a situation that I have been trying to figure out with Mitel with no success so far.

We have a customer with a single MBG in their network for SIP trunks. Currently they are setup in Server-Gateway Mode with the first LAN NIC setup on the Voice Network and the WAN NIC and Gateway setup on the SIP Providers LAN. In this configuration it sets the SET-SIDE Streaming Address to the SIP Providers WAN Interface and the ICP-SIDE Streaming Address to the LAN Interface; all works as expected.

Now, the customer wants to add Teleworker phones into the mix and I have been unable, up to this point, to get it working. Mitel had me change the server configuration to the following.

Reconfigured the server to set both NICs to be LAN NICs as follows.

LAN NIC 1: Voice Network
LAN NIC 2: SIP Provider Network
Gateway: Tried Both Voice Network & SIP Provider Network; no difference

Then I went into the Network Profile and created a Custom Mode Profile
SET-SIDE Streaming Address: Public IP Address pointed to LAN NIC 1
ICP-SIDE Streaming Address: LAN NIC 1

After that I went to SIP Trunking and set the following.
Remote Trunk Endpoint Address: Carriers LAN IP Address
RTP Address Override: Third Interface [LAN NIC 2]

After setting that all up I Stopped and Started the MBG Service as required due to the RTP Address Override and tested.

The MBG was able to get to the AMC with no problems so licensing is good. I then called into the system from cell phone and answered the call on one of the desk phones. At that point I didn't have audio in either direction, and after a few seconds the cell phone got a busy signal while the desk phone still had no audio. I currently had the Gateway for the MBG setup for the SIP Provider's Gateway Address. After changing the Gateway to the Voice Network there was no change to how this was working.

Next I tried to make a call from the Teleworker phone to a phone on the Main Campus. The desk phone was able to hear the teleworker phone with no problem, but the teleworker phone was unable to hear anything. So, I reconfigured the server to change the Gateway Address to the Voice Network and tested again; no difference.

So, at this point, I put everything back the way it was so they can at least get calls in and out of the system. If anyone has any ideas on how to make this happen I would appreciate it. I am still working with Mitel on this as well to see if we can get it working, but their next step was to make both NICs setup as WAN Interfaces, but I couldn't figure out how to do that.

Thanks,

TE

P.S. - I have attached a pdf of a very high level drawing on how this is setup.

[dilkie]

I think what you need to do configure msl with eth0 as lan, eth1 as WAN (internet connected) and eth2 as the "third" interface.

then configure MBG in normal server-gateway mode but configure the trunk with an override.

[Tech Electronics]

dilkie,

All I have are two NICs in the system with no way to add a third NIC. So, eth0 is physically connected to a switch port that is tagged for the Voice VLAN and eth1 is physically connected to the customers router interface setup for the SIP Providers VLAN.

I may be able to get the customer to reconfigure their network though to make this happen now that I think of it; it is a virtual server. So I would need 3 virtual NICs

eth0 would be on the Voice VLAN
eth1 would be setup as the WAN interface on the Voice VLAN or possibly on a different VLAN in the DMZ? This is where I am not tracking I guess.
eth2 would be on the SIP Providers VLAN

Thanks,

TE

[johnp]

It may be easier to and another vMBG and cluster, cost is cheap as compared to labor spent usually IMHO

[acejavelin]

I gave to agree with johnp here... I have tried to do this before, worked with support for several hours just to come to this conclusion. It easier to get another MBG for the phones (or another SBC for the SIP trunks) than it is to work for days trying to figure this out.

TBH, the only way I have made one MBG work for phones and SIP trunks simultaneously is if SIP trunks are purely cloud based, I have never been able to get it to work with a "3rd" NIC connection.

[dilkie]

hmmm, interesting.. I know this is deployed like this, especially in the EU where "carrier sip trunks" come in over private network connections and not the internet...

but now I'll have to try this out myself, curiosity.

[Tech Electronics]

dilkie,

In this situation the SIP Provider and the Internet Provider are actually one and the same. So, the Router that provides the SIP Trunks is the same as the Router that provides the Internet. The only one who can program that router is the Provider and they setup one Interface on their router for the SIP Trunks and another for the customers Internet. There are a few more setup for MPLS circuits connecting other sites and a failover which uses up all of the interfaces on the Providers router; although another card could be added.

As I think about this it could be a situation where the router sees a hairpinning situation and it isn't setup for it and therefore it drops the packets for all the SIP calls. As for why Teleworker has audio only in one direction I haven't come up with a logical explanation for that one yet.

So, when you set this up is the Provider coming in on a completely different router than the Internet would be coming in on?

Thanks,

TE

[dilkie]

so, these are separate connections (ending in different interfaces on msl) to different subnets.. and no NAT is involved either?

[Tech Electronics]

dilkie,

If you looked at the pdf I attached you will see that one MSL interface is connected directly to the SIP Provider Router with no NAT. The other MSL interface is on the Voice VLAN and the Public IP going to it for the AWC and MiCollab Clients are via NAT.

Thanks,

TE

[dilkie]

Ah, pictures help...

so you've configured nic2 to have two ip addresses, the mbg public (internet) address and the address the sip provider gives you(out of some sort of /31? private network)?

that should work, as long as the default route is to the internet and the sip provider is anchoring all the media at it's far end.

[Tech Electronics]

dilkie,

Actually no, if you notice there are two different colored lines [red and blue]. The Red is for the SIP Provider coming into the Router and the Blue is for the Public IP [Internet] coming into the router and the routes they take. So, the Public IP routed via NAT to NIC 1 and the SIP Provider is routed directly to NIC 2.

So the Public IP  is how the Teleworker phone gets to the Router and then is routed through the Firewall to the Core Switch and then on to the MCD via the MBG.

SIP Calls come in through the SIP Provider to the Router then on to the MCD via the MBG.

Thanks,

TE

[dilkie]

Oh, I see... yeah, well, that's not going to work. MBG isn't really in server-gateway mode (because it's wan interface isn't programmed with the "real" public ip). So I assume you are using a custom mode with set-side streaming address set to the public ip (owned by the f/w).

but I think you'll run afoul of msl's natting and routing in this setup. not to mention a few other issues (like hairpinning rtp, which will get dropped).

[johnp]

Think he may be in server-gateway, but private ip's on both instead of routing

[pkriek]

hi TE

where you able to solve this?
we have exactly the same situation with a new mbg setup.
it is setup with 2 NICS and should handle TW phones over the internet, and a sip trunk. When using a TW Phone, calls in and outbound over the sip trunk are perfect. When using an office phone, so routed thru the MBG, we have exactly the issue you describe.

Funny thing is that we do have this setuo working in another datacenter. Settings are all teh same, and there we have no issues.....

Patrick

[Tech Electronics]

pkriek,

No, as of this moment I do not have it working. I will however be working on it this Wednesday again with another configuration that Mitel provided. I will update this thread if I get it working.

Sorry,

TE