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Device vs Line CSS in EM Deployment?

Rising star
Rising star



In an Extension Mobility deployment, are the device and line CSS concatenated together?


For example, if we have a phone which is not logged into EM. It has a DN of 5555 and its CSS for both device and line are set to only allow emergency dialing and nothing else.


A user then logs into the phone and they have a line CSS which allows internal and external dialing but DOES NOT have the partitions which allow the emergency route patterns to be dialed.


If device and line CSS are concatenated then you would assume the user can dial emergency numbers right as the device CSS allows access to the emergency route patterns even though the EM users line CSS does not?


This is the issue we have. When a user logs into a phone via EM, they cannot dial the emergency numbers despite the phones device CSS having access to those RP's.


Am I misunderstanding this?



5 Replies 5

Roger Kallberg
VIP Expert VIP Expert
VIP Expert

This operate the same way as for any line and device CSS setup, meaning that yes it's concatenated. You'd need to look at the traces to see why a user can't make calls to emergency services.

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Mohammed al Baqari
VIP Advisor VIP Advisor
VIP Advisor

If the CSS is assigned to the device for emergency then calls should work
after login. However, it seems that you might be having an overlapping
route pattern accessed from the CSS of the EM DN which supersedes the
partition of phone CSS.

Use DNA, https://cucm-ip/dna to see which pattern is matched from the EM

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Hi Mohammed


Thanks for taking the time to reply.


So to test the theory of an overlapping route pattern in the EM Line CSS, I added my Mobile phone in as a specific entry in the same route partition as the emergency numbers.


So 9.07XXXXXXXXX now exists in the Emergency partition which is only accessible via the Device CSS and non the EM line CSS.

I then called it (and used DNA) and although it rang, its matching the 9.@ Route Pattern in the Line CSS.

Surely if they are concatenated then it should match the more specific route pattern in the Emergency partition?


My understanding is that CUCM does longest match routing, irrespective of the partition order in the CSS. Then only time the partition order comes into play is for matches which are identical and then it picks the top one.


In my test, they are not identical. The 9.07XXXXXXXXX pattern is more specific than 9.@ which works fine if they are in one or more partitions as part of the EM line css but if the more specific pattern is part of the device CSS and the 9.@ part of the line CSS, its picking the 9.@ one?


Suggest that you don't use 9.@ patterns as it's a nasty little filthy thing that only will give you grey hair and make you age faster. If you do still want to keep this pattern make sure it's not set to urgent priority.

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We are planning to do away with 9.@. its a legacy configuration which needs a lot of planning to get rid of. Getting the emergency services working for logged out EM phones is the first step.


I think I figured out where I went wrong on this, I added my mobile as a route pattern without the 9 Prefix so just 07XXXXXXXXX into the Emergency partition and it worked fine when logged out and whilst logged in and because this didn't match 9.@, it must be concatenating them otherwise it would not have worked at all.


Thanks all for help

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