VoIP SCN Backup

[jjdad]

Hello to all.

I am working on situation where I have two IPO system (5.0) tied together via SCN with VM Pro at the main site. Lately we have had issues where the MPLS link for the VoIP (SCN) between the sites has gone done quite often, sometimes for days.

There are a lot of calls that are placed between the sites and when the MPLS goes down it causes all kinds of issues, plus the remote office cannot get into their Voicemail.

I do have a VPN setup via internet connections between the sites that can be used to dial between the sites using a short code and that works well, but it doesn't take care of the Voicemail issue.

When the MPLS is down for long periods, I will reprogram the systems to use the VPN as the SCN route so the Voicemail will work. While this fixes the initial problem, I still have to manually make the change, which I sometimes can't get to immediately, causing the customer problems. I would like this to be automatic if possible.

I have actually set both the MPLS and VPN Lines to SCN and the system does seem to work, but it always wants to route the calls over the VPN first instead of the MPLS. If I pulled the plug on the VPN it will route over the MPLS, but that is backwards, I want the MPLS to be the primary.

With the limitations of SCN only allowing a star configuration, while supposedly not allowing mesh configurations, is there a way to have the VPN be used as a backup via SCN Failover, or dual SCN, or something, so that if the main MPLS does go down the VoIP traffic AND the Voicemail will be routed over the VPN and when the MPLS comes back up, the traffic is automatically routed back over the MPLS like it should?

There are NO IP phones on this system.

Having tried several different SCN settings and reading through the manuals has not given me a straightforward answer.


Primary route: Site 1 (LAN2) ---- SCN (MPLS) SCN ---- (LAN2) Site 2

Secondary route: Site 1 (LAN1) ---- VPN (Internet) VPN ---- (LAN1) Site 2



All help is appreciated. THANKS!

 

[tlpeter]

Try this.

Make an iptrunk with SCN on but use Lan 2 on both systems.
This way it will allow you to use a second trunk.
You cannot use the same gateway ip address in the iptrunk.

But u think it will cause issues.

You better solve the problem instead of trying this kind of stuff.


BAZINGA!

I'm not insane, my mother had me tested!

 

[mattKnight]

You are overcomplicating this. You should not do this with the IP trunks. The trunks are an application layer (not strictly true - but close enough) service that runs over the network. The network is responsible for getting the packets to the right destination. So, I think that you should be doing this with IP routing.

Currently the IP office knows how to route to the other side over MPLS, if that route fails, you should fail over to the VPN with out manual intervention. This is called dynamic routing.



Take Care

Matt
I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.

 

[hairlessupportmonkey]

MPLS failing often?

you paying nothing for it, or is it just a shit service you are getting?

ACSS - SME
General Geek

 

[jjdad]

*


Thanks those who have answered already.

Yes I agree the problem with the MPLS should be fixed, but the sites are in a rural area and I have a mutiple choice of just ONE carrier for the MPLS, so I have to work with what I've got.

And yes, the service has gotten really crappy lately. The major carrier sold the service to a smaller carrier that can't keep things working as well.



IPO 1 ---------- [Internet router] --- Internet Cloud --- [Internet router]---------- IPO 2
(LAN1) (192.168.0.250) (LAN1) (192.168.1.250)
-------------------------------------------------------------------------------------------------------------------
IPO 1 ---------- [MPLS router] --------- MPLS Cloud -------- [MPLS router]----------- IPO 2
(LAN2) (10.10.0.250) (LAN2) (10.10.1.250)


OK, maybe I wasn't quite clear on this...it had been a long day when I posted.

Each site has an IP Office (5.0) system.

The LAN 1 side on each end is connected through a standard network which is connected to the internet via Cable modem.

The LAN 2 port on each site is connected directly to a Cisco MPLS router that is setup as a Point to Point T1 (MPLS) with QoS circuit.

The MPLS circuit carries ONLY VoIP traffic between the sites.

The VPN circuit is used for remote programming and as a backup VoIP line.

I have all the IP routing in place, and each LAN works individually the way it is supposed to.

This system has been in place for over two years and normally works well.

The issues began recently when I upgraded them to VM Pro from Embedded VM.

Before, if the MPLS went down, they simply started using the short codes to dial between offices and since each site had their own Embedded VM, VM was not an issue.

With the upgrade to VM Pro, when the MPLS goes down, they can still use the backup VPN via short code to dial between offices, but they lose the VM Pro accessibility from the remote site.

What I am trying to accomplish here is a way to program each IP Office system to have what I would call a dual SCN with priority.

Under normal conditions, the SCN would work via the MPLS circuit. However if that circuit went down, I want the system to recognize the circuit loss and then route the SCN over the VPN circuit automatically. When the MPLS circuit comes back up, the traffic would switch back to the MPLS circuit.

I realize what I am asking for is not supposed to be setup this way per Avaya because they don't want to support it, but I'm not worried about that type of support. I just want the customer to have a fail safe system.

What I discovered is that I could program two lines:

Line 200: over LAN 2 via the MPLS to the other system

Line 201: over LAN 1 via the VPN to the other system

Set both lines 200 and 201 to SCN under the VoIP tab.

Both IPO's recognized the config, and I could make calls (without short code) to each site with no problem, except it ALWAYS chose to use the VPN circuit first. If I disconnected LAN 1 on either side, the calls would then go over the MPLS via LAN 2 automatically. When I re-connected LAN 1, the calls would then start going over the VPN again. This works great EXCEPT, I want the calls to go over the MPLS (LAN 2) circuit first and use the VPN (LAN 1)as a backup.

 

[hairlessupportmonkey]

how about the MPLS provider an ADSL backup instead?

ACSS - SME
General Geek

 

[mattKnight]

What I am trying to accomplish here is a way to program each IP Office system to have what I would call a dual SCN with priority."

I'll say it again

You need to understand IP routing.

There is no need to build a second SCN trunk

Take Care

Matt
I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.

 

[jplissonneau]

Agreed. Your (failover) routing should be done by your routers, not the IPO.

Your routers would have two routes to the same remote network, one with a lower priority (= higher "metric") than the other. When the higher priority one is known to be unreachable by the router (and this could be the tricky part), your packets will be automatically and instantly forwarded through the fallback route the good old Internet way. Without even losing your current calls if you detect and switch fast enough (there will be a blank though).

About the tricky part now (which I suspect is also a problem with what you are currently attempting to do with the IPO). The way I would handle that would be to add a layer of VPN above the MPLS link in order to be able to monitor the link with keepalives. Keepalive fails -> VPN interfaces go down -> routing goes the other way. You may even need to monitor further than that, e.g. avoid a route where packet loss / delay is already beyond a threshold (with hysteresis).

Without the "monitor" part, you are depending on higher level protocols to time out, which takes time, and you won't have much control over that.


--
A(PS|CI)S-SMEC
IT consultant
Canada / Quebec City area

 

[piethief]

No matter what IP line you direct calls over through ARS, the issue you will run into is that the voice mail service on the remote side is set to a specific VOIP line group. When the MPLS fails, so will the voicemail. The only way to accomplish what you want is to have routers with automatic fail-overs in place.

 

[amriddle01]

No need for a second trunk or to uyse the routers to do the failover, as the system can also do the failover via it's own routing and using the same Metric process mentioned above.

If you have a specific route set to the other system in IP routes using the router that handales the MPLS (on LAN2)as the gateway then you can add a second identical route but with a higher metric that targets the VPN router (on LAN1) as it's gateway.

If the system can't talk via the first route it will try the second route automatically

http://www.ipoffice.tel

 

[jplissonneau]

The problem with static routing done on the IPO is that "can't talk via the first route" actually means "the interface that would be used to send packets to the router is down". Your ethernet interface will stay up even if the router on the same lan segment stops responding, and your packets will continue to go nowhere.


--
A(PS|CI)S-SMEC
IT consultant
Canada / Quebec City area

 

[amriddle01]

It doesn't depend on the interface being down at all, it's if it gets no ack's or replies from data sent, I have done it before

http://www.ipoffice.tel

 

[jplissonneau]

How does it know that the route is available again then?


--
A(PS|CI)S-SMEC
IT consultant
Canada / Quebec City area

 

[tlpeter]

It will check on every call.


BAZINGA!

I'm not insane, my mother had me tested!

 

[jplissonneau]

Which is "depending on higher level protocols to time out". For every call.

Works, but a router that can monitor link quality would work better and even use the other route if the link goes down in the middle of a call. Probably without even losing the call (there will be a blank for the time it takes for the router to decide that the link is gone, and that can be configured).


--
A(PS|CI)S-SMEC
IT consultant
Canada / Quebec City area

 

[amriddle01]

Indeed, but as we do not know what he has available in network equipment or skill and as this is within the features of the system, we have advised accordingly, there is always a better way of doing it, just depends how much time and money you have

http://www.ipoffice.tel

 

[mattKnight]

>Indeed, but as we do not know what he has available in network equipment or skill and as this is within the features of the system

My preference woudl be 2 cisco routers running HSRP and both router running BGP...

But that ain't going to happen.

This is why my reponses were device agnostic

Take Care

Matt
I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.

 

[piethief]

Limitations exist. You can always route calls through ARS to a backup ARS that will check on every call, but you will still have VM issues. Better routers is the true solution.