CSS with Extension Mobility

[Carl Ratcliffe]

Hi Support Community

Please could somebody give me their expert opinion on this query.

• Within a single cluster Extension Mobility is used.
  
• The devices use the device and line approach for CSS, lines CSS contains nothing except blocks to specific patterns.
  
• Local Route Groups are used for all sites within the cluster.
  
• The dial plan is currently country specific so each country has route patterns which only devices in that country have a CSS for. So for example we use 1 dial plan for the USA, another dial plan for Brazil but each of these countries have multiple sites which is were the Local Route Groups come into it.
  

So within a country the user dials a number, CSS matches partition of local route pattern which in turn sends the call to the route list then onto Local Route Group. This all works as expected.

Now if i am an extension mobility user and move from the USA to Brazil and use a hot desk phone in Brazil configured with Brazil settings, from what i understand, my line CSS will remain the same when i log into EM but this is only used to block patterns not route calls. My device CSS will be whatever is assigned to devices in that country and because the physical phone belongs to that country it wont use device mobility settings because as far as CUCM is concerned the phone is in its correct location.

Therefore i have a device CSS of Brazil and a line CSS of USA which is just used to block calls within the USA dial plan. So my query is for this user to be able to dial as though he was in the USA what is the best approach, is there a way the UDP can be assigned a new device level CSS although the phone physically belongs to the remote destination or do i need to add route patterns in that are for USA dial plan but can be dialled by Brazil phones ?

Thanks, Carl

[Ayodeji Okanlawon]

Carl,

Your line CSS should not only be used to block calls but also should have your user COS. You block calls you want to block and you allow calls you want to allow..This way when a user moves around their class of control or calling priviliges remain the same..

eg USER A (USA--has access to call local numbers only)

Line+css= block premium,long distance, international

dev+css= allow all

When this user moves to Brazil, the calling privileges remain the same

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[Carl Ratcliffe]

Hi and thanks for the quick response.

Makes sense, it did cross my mind of applying the dial plan partitions to the line CSS. The traditional device / line CSS approach i suppose were you allow on the device and block on the line is only really applicable when you have users who are not roaming between sites within the same cluster.

I know that if you move a phone i.e IP Communicator to another location you can pickup romaing settings like CSS and i wasnt sure if you could do this with a UDP profile.

So leading on from this query we are using  Extension Mobility Cross Cluster in other clusters, when used the EMCC CSS of the UDP becomes the new device CSS, your line CSS reamains unchanged, so if i use the line CSS to allow calls then because line takes priorty over device my calls will route as per the line CSS, the poblem with this is that Local Route Groups dont really work well with EMCC so for EMCC call routing we use different route patterns that only the EMCC CSS has access to and basically calls wont use Local Route Groups using this method. However if the line CSS takes priorty then calls will still route to SLRG becasue the pattern will be hit on the line before the device. So to get round this would it be best to use the Adjunct CSS to route without SLRG becasue i belive this will then take priorty over the line ?

Thanks, Carl

[Carl Ratcliffe]

Hi all

Using allow partitions on the line CSS although it allows a roaming user to continue using their home dial this is only the case if you are not using standard local route groups. If you make a call it will use the route group in the device pool.

This is because we have managed to use a globalised e. 164 dial plan which is shared by many countries so translations patterns / route patterns are minimal and simplified.

So are we thinking that to properly use css with em standard local route groups although recommended by cisco to simplify the dial plan won't actually work together therefore you need to go back to using a complex dial plan for each country?

This is unless anyone can think of another way?

Thanks, Carl




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[Ayodeji Okanlawon]

Carl,

First of all your original post didnt say you were using Cross cluster EM. I just assume you are using a single cluster..

Now there are different ways to do this, with your local route group

1. Use a full E164 dial plan for your offnet dialling across all sites

2. use your line css to control call routing only. Your dev css should be used only for emergency calls

3. Your line css has to be country specific

4. Globalize all call PSTN calls to the gateway and normalize at the gateway before calls are presented to the PSTN

Example..

User A in UK...

Line css= CSS-UK-NAT-PSTN (can call National and Mobile numbers)

User B in brazil

line-css= CSS-BRA-INT-PSTN (can call international numbers)

NB: With this users maintain their dialling habits wherever they go...

Call routing..

A user A in UK dials 9+ any digits to make outside calls..

The call matches a xlation pattern, which globalizes the call to full e164.

The call is then sent to the local gateway..At the local gateway dialled number is normalized and sent to the PSTN

The same user goes to Brazil,

Dials 9+any digits (just as he does when in home location)

The call matches a xlation pattern, which globalizes the call to full e164.

because LRG is in use, the call is sent to the brazil local gateway..

At the gateway, call is normalized and sent as international call...

When this user wants to dial a brazil pstn number, he dials as if he is calling and international number. 900XXXXX

Because his line CSS doesnt have access to international dialling, it is blocked..

With this the user dialling experience is the same wherever he goes.

You also implement your short dials on the line css...

The other way to do this using device/line css and blocking patterns on the line is very cumbersome but can work

1. For each user you will have to configure a matching block pattern on the line for all the sites provisioned on your clusters

eg..user a in uk, line css= uk-block-int, us-block-int, bra-block-int

So when the user goes to remote location, and the local gateway is used, the blocked pattern will be applied per location.

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[Carl Ratcliffe]

Hi aokanlawon

Thanks for taking the time and thanks for a good explaination.

Cross Cluster EM is used across 2 clusters currently and addiitonal clusters are to be added. We are also already using Globalisation in many countries so globalising at the ingress and localising at the egress and more are being added as we improve the dial plan.

I will use the example you gave just to expand a little further, this is without EMCC configured. We want to keep user dialling habits as you mention so no matter what location they are in they dial the same :

A user A in UK dials 9+ any digits to make outside calls..

The call matches a xlation pattern, which globalizes the call to full e164.

The call is then sent to the local gateway..At the local gateway dialled number is normalized and sent to the PSTN

## this is correct and is exactly is what is happening if your are in your home country location, you dial and LRG is used so UK users out of UK gateway and Brazil users out of Brazil gateway ##

The same user goes to Brazil,

Dials 9+any digits (just as he does when in home location)

The call matches a xlation pattern, which globalizes the call to full e164.

because LRG is in use, the call is sent to the brazil local gateway..

At the gateway, call is normalized and sent as international call...

## this is exactly what we dont want to happen, how we would like it to work is that users dials as normal but the gateway in the UK is used to route the call, we dont want to make an international call when it can go TEHO ##

So as a phone uses the device pool for LRG and the phone is static in a location the only way i can think of doing this is not to use LRG as we have no way of changing the route group as this is selected from the device pool ?

Thanks, Carl

[Ayodeji Okanlawon]

Yes Carl, you will have to do this without LRG.  Your other option is to configure specific route patterns for TEHO..I think this is a better approach...you will need to ensure the CSS of the remote devices has access to the partition of the TEHO pattern. With this approach you keep your existing call routing architecture and just add TEHO to it