Is there anyway to set up DID redundancy between carriers?

[victoriabardy]

Hello all,

We had a carrier outage yesterday and we were able to point our end users to a different office gateway so they could get outside dialtone but anyone calling the DIDs for our office was out of luck and we had some very important client business that suffered as a result.  The question has been posed, is there anyway to fail DID's over to a different circuit?  Could we do this if we were using SIIP trunks as opposed to traditional PRI circuits?

Any feedback would be great here.

Thank you.

Rgds,

Vicky

[Chris Deren]

Well, you would need other DIDs on the other carrier and see if your carrier can do CLAR type service, it would need to be one to one relationship for your DIDs, so you would end up owning twice as many DIDs as 2 carriers cannot own the same DID number.

HTH,

Chris

[victoriabardy]

Hi Chris,

This is pretty much what I have tried to explain.  Do you know if moving to a SIP trunk would provide any additional options in this scenario?  I believe SIP trunking frees you up from the physical restrictions of a standard PRI.  If I understand this correctly, if we have more than one office in a SIP network, if there is a local outage, the DID can be kept active and will ride a different SIP trunk. I found some info on the internet (see below) but I am not sure if I am understanding this correctly.  Do you know?

What are the benefits of SIP trunking?

• Flexible numbering - for example allows your customers to work from London on a Glasgow number
  

Thank you for getting back to me.

Rgds,

Vicky

[Chris Deren]

Vicky,

You can definitely have that with SIP if the SIP provider is the same at other locations, your original question was in regards to having 2 providers, that will not be available with any type of service due to legal/regulatory restrictions.  If you have multiple SIP trunks at multiple locations and they can definitely provide failover, in fact I have done it few times, my recent project had centralized SIP trunk in Chicago and NY fully redundant, able to route DID calls from around 30 remote locations scattered all over US.

HTH,

Chris

[victoriabardy]

Hi Chris,

This definitely helps!  I have just been assigned a SIP project as well.  So in order to create this kind of flexability we would need to convert a few of our Cisco Voip offices to SIP from their current traditional PRI's.  Correct?

Also we would need to convert the current remote site gateways to CUBE gateways, am I right?

Thank you again for your help here.

Rgds,

Vicky

[Chris Deren]

Yes, if you want distributed SIP trunking then you will definitely need CUBE at each site.

Chris

[victoriabardy]

Thank you again Chris.

[victoriabardy]

Hi Chris,

We are exploring SIP further and speaking with our vendor regarding design.  I remember from our previous discussion here that you mentioned a recent project where you set up a centralized SIP trunk in Chicago and NY fully redundant, able to route DID calls from around 30 remote locations scattered all over US.

My question here is, how many routers are involved in that build out?  Do you have local gateway routers or just 2 routers, 1 in Chicago and 1 in NY?  Our vendor is advising we keep our gateways and set up some pots lines at each for local redundancy in case the sip trunk goes down.  Just wondering how you are built out and what you are doing for local 911 calls?  If you could share your experience it would be helpful.

Thank you again.

Rgds,

Vicky

[Chris Deren]

Vicky,

In my design I had CUBE router in Chicago and NY and each remote site had an SRST GW with some backup POTS lines to be used under SRST for outbound calling.  E911 was also handled by SIP trunk provider as that was an option available, so all remote location 911 calls went out of the SIP trunks and were routed properly to local PSAP centers.

Chris

[James Hawkins]

Hi Vicky,

Some ISDN providers offer enhanced resilience services to allow DDI resilience - check out the link below to see what BT offer in the UK.

http://business.bt.com/phone-services/isdn/isdn30-assurance-continuity/

An alternative approach which some of my customers do is use non-geographic numbers which can be remapped to geographic numbers using a web portal (or by instructing the carrier). This requires manual intervention to swap the destination but can work well if combined with say Embedded Event Manager configured to send emails if an E1 goes down.