CSS query

Answered Question
Jan 31st, 2008

Guys,

I have a very basic query. What's the difference between appying Calling Search Place on the phone configuration page ( 1st page) & the line configuration page ( 2nd page) ?

I have this problem too.
0 votes
Correct Answer by Rob Huffman about 8 years 12 months ago

Hi Abhijit,

Thanks for your kind words! For the question regarding the SRND reference to CCM 4.2, this was only in reference to User Device Profiles and Extension Mobility. The different rules for Device Level vs Line/Device Level CSS's are still applicable.

For your second question, take a close look at your CSS's. Are all the available Partitions (including the Local **non-Toll partition) listed as "Selected" under the International CSS? It seems like this phone that didn't have the CSS set on the Line may have been able to dial International but not dial 9 Local due to the Selected Partitions under International, did you try?

Please compare the CSS settings to one of your working phones.

Hope this helps!

Rob

Correct Answer by Zin.Karzazi about 8 years 12 months ago

The Key word here is "concatenates", here you go:

If you configure a calling search space both on an IP phone line and on the device (IP phone) itself, Cisco CallManager concatenates the two calling search spaces and places the line calling search space in front of the device calling search space. If the same route pattern appears in two partitions, one contained in the line calling search space and one contained in the device calling search space, then Cisco CallManager selects the route pattern that is listed first in the concatenated list of partitions (in this case, the route pattern that is associated with the line calling search space).

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/4_0_1/ccmsys/a03ptcss.html

Correct Answer by Rob Huffman about 8 years 12 months ago

Hi Abhijit,

Hope all is well! This is actually a little complicated to try and explain without some visuals. We do know that the Device Level CSS is easier to configure for Single-Site deployments but becomes very complicated and config intensive for Multi-Site deployments. When using the combination of Line/Device (recommended for Multi-Site) a combination of the two CSS levels is used to provide Calling restrictions/routing. Here are some clips along with links to an "in-depth" look;

Classes of Service with the Device CSS - Single-site deployment

With Cisco Unified CallManager, you can define classes of service for IP Telephony users by combining partitions and device calling search spaces with external route patterns, as follows:

•Place external route patterns in partitions associated with the destinations they can call. While you could place all route patterns in a single partition, you can achieve more refined call restriction policies by associating the route patterns with partitions according to the destinations they can call. For example, if you place local and international route patterns in the same partition, then all users can reach both local and international destinations, which might not be desirable. Cisco recommends that you group route patterns in partitions according to the reachability policies for the various classes of service.

•Configure each calling search space to be able to reach only the partitions associated with its call restriction policy. For example, configure the local calling search space to point to the internal and local partitions, so that users assigned to this calling search space can place only internal and local calls.

•Assign these calling search spaces to the phones by configuring them on the Cisco Unified CallManager device pages. In this way, all lines configured on the device automatically receive the same class of service.

With this approach, the device calling search space performs two distinct logical functions:

•Path selection

The calling search space contains specific partitions, which in turn contain specific route patterns that point to specific PSTN gateways through route lists and their associated route groups.

•Class of service

By selectively including certain partitions and not others in the device calling search space, you effectively apply calling restrictions to certain groups of users.

As a consequence, when you apply this approach to a multisite deployment with centralized call processing, you have to replicate partitions and calling search spaces for each site because for each site you have to create classes of service and, at the same time, route the PSTN calls out of the local branch gateways

continued on next page .....

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Correct Answer
Rob Huffman Thu, 01/31/2008 - 06:10

Hi Abhijit,

Hope all is well! This is actually a little complicated to try and explain without some visuals. We do know that the Device Level CSS is easier to configure for Single-Site deployments but becomes very complicated and config intensive for Multi-Site deployments. When using the combination of Line/Device (recommended for Multi-Site) a combination of the two CSS levels is used to provide Calling restrictions/routing. Here are some clips along with links to an "in-depth" look;

Classes of Service with the Device CSS - Single-site deployment

With Cisco Unified CallManager, you can define classes of service for IP Telephony users by combining partitions and device calling search spaces with external route patterns, as follows:

•Place external route patterns in partitions associated with the destinations they can call. While you could place all route patterns in a single partition, you can achieve more refined call restriction policies by associating the route patterns with partitions according to the destinations they can call. For example, if you place local and international route patterns in the same partition, then all users can reach both local and international destinations, which might not be desirable. Cisco recommends that you group route patterns in partitions according to the reachability policies for the various classes of service.

•Configure each calling search space to be able to reach only the partitions associated with its call restriction policy. For example, configure the local calling search space to point to the internal and local partitions, so that users assigned to this calling search space can place only internal and local calls.

•Assign these calling search spaces to the phones by configuring them on the Cisco Unified CallManager device pages. In this way, all lines configured on the device automatically receive the same class of service.

With this approach, the device calling search space performs two distinct logical functions:

•Path selection

The calling search space contains specific partitions, which in turn contain specific route patterns that point to specific PSTN gateways through route lists and their associated route groups.

•Class of service

By selectively including certain partitions and not others in the device calling search space, you effectively apply calling restrictions to certain groups of users.

As a consequence, when you apply this approach to a multisite deployment with centralized call processing, you have to replicate partitions and calling search spaces for each site because for each site you have to create classes of service and, at the same time, route the PSTN calls out of the local branch gateways

continued on next page .....

Rob Huffman Thu, 01/31/2008 - 06:11

.....from previous

Classes of Service with the Line/Device Approach - Multi-Site Deployments

The traditional approach outlined in the preceding section can result in a large number of partitions and calling search spaces when applied to large multisite deployments with centralized call processing. This configuration is required because the device calling search space is used to determine both the path selection (which PSTN gateway to use for external calls) and the class of service.

It is possible to significantly decrease the total number of partitions and calling search spaces needed by dividing these two functions between the line calling search space and the device calling search space, in what is called the line/device approach.

Keeping in mind how the line calling search space and the device calling search space for each given IP phone are combined within Cisco Unified CallManager, and how the line calling search space partitions appear first in the resulting calling search space (see Calling Privileges in Cisco Unified CallManager), you can apply the following general rules to the line/device approach:

•Use the device calling search space to provide call routing information (for example, which gateway to select for PSTN calls).

•Use the line calling search space to provide class-of-service information (for example, which calls to allow).

When applied to centralized call processing deployments with large numbers of sites, the line/device approach drastically reduces the number of partitions and calling search spaces needed. For example, a deployment with 100 remote sites and 4 classes of service requires at least 401 partitions and 400 calling search spaces with the traditional approach but only 105 partitions and 104 calling search spaces with the line/device approach.

However, the line/device approach relies on the fact that you can globally identify the types of PSTN calls that must be restricted for certain classes of service (for example, local, long-distance, and international calls). If the national numbering plan of your country does not allow this global identification of the different types of calls, the efficiency of this approach (in terms of configuration savings) is lower than that indicated in the formulas above.

For example, in France the numbering plan is based on five area codes, from 01 to 05 (plus the 06 area code for cellular phones), followed by eight digits for the subscriber number. The key characteristic is that each PSTN destination is reached by dialing exactly the same number (for example, 01XXXXXXXX for Paris numbers, 04XXXXXXXX for Nice numbers, and so on), whether calling from the same local area or from a different area. This means that it is not possible to block access to long-distance calls with a single partition and a single route pattern because the concept of "long-distance call" changes depending on the area where the calling party is located. (For example, a call to 014455667788 is a local call if the caller is in Paris but a long-distance call is the caller is in Nice or Lyon.)

In such cases, you will have to configure additional sets of blocking calling search spaces and partitions, one for each area within which local and long distance calls are dialed the same way. In the example of France, you would have to defining five additional blocking calling search spaces and partitions, one for each area code.

Described in detail in the CCM - SRND;

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/4x/42dialpl.html#wp1044899

And nicely shown here;

Voice Dial Plan Interactive Voice Network Configuration Example

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a00807f54af.shtml

Hope this helps!

Rob

UCBNOCWAN Thu, 01/31/2008 - 08:35

Hi Rob,

Pray that all is well from your end. Thanks a ton again for this great info. Just one small question though - We are running CCM 4.1(3) & the doc says that this is applicable from 4.2x. Hence will setting different CSS's on the device & line page affect anything on 4.1(3) ? Should the device CSS be the default CSS on 4.1(3) & the line CSS is irrelevant here?

Have a nice day.

Thanks & Regards,

Abhijit Das.

Correct Answer
Zin.Karzazi Thu, 01/31/2008 - 06:11

The Key word here is "concatenates", here you go:

If you configure a calling search space both on an IP phone line and on the device (IP phone) itself, Cisco CallManager concatenates the two calling search spaces and places the line calling search space in front of the device calling search space. If the same route pattern appears in two partitions, one contained in the line calling search space and one contained in the device calling search space, then Cisco CallManager selects the route pattern that is listed first in the concatenated list of partitions (in this case, the route pattern that is associated with the line calling search space).

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/4_0_1/ccmsys/a03ptcss.html

UCBNOCWAN Thu, 01/31/2008 - 08:52

Zin,

thanks for your help. Let me explain in detail why I am asking this question:

In the Device CSS in our organization the caller has international dialing rights, whereas in Line CSS by default it's "None". With the concatenation of 2 CSS's, the user should still be able to dial International calls, correct? ( since Device CSS still has rights & CCM should parse it also while attempting to place a call). Normally we make changes in both the Line & Device CSS & allow International calls. For one user we forgot to check Line CSS for International calls, but Device CSS was configured for international calls. The user was not able to dial outside the gateway but internal calls were going fine. We are using CCM 4.1(3). Can you help here again?

Thanks & Regards,

Abhijit Das.

Correct Answer
Rob Huffman Thu, 01/31/2008 - 09:53

Hi Abhijit,

Thanks for your kind words! For the question regarding the SRND reference to CCM 4.2, this was only in reference to User Device Profiles and Extension Mobility. The different rules for Device Level vs Line/Device Level CSS's are still applicable.

For your second question, take a close look at your CSS's. Are all the available Partitions (including the Local **non-Toll partition) listed as "Selected" under the International CSS? It seems like this phone that didn't have the CSS set on the Line may have been able to dial International but not dial 9 Local due to the Selected Partitions under International, did you try?

Please compare the CSS settings to one of your working phones.

Hope this helps!

Rob

Zin.Karzazi Thu, 01/31/2008 - 10:05

Also to add to what Rob said, use the DNA (https://ip/dna), select Gateways and verify what exactly the Callmanager is selecting as CSS. Also check if your Phone have the right Device Pool..etc assigned.

UCBNOCWAN Fri, 02/01/2008 - 06:13

Thanks Zin, as explained to Bob, the issue is resolved now. Thanks for your kind assistance.

Have a nice weekend

UCBNOCWAN Fri, 02/01/2008 - 06:10

Hi Rob,

Many thanks here. Actually today I found out that my Team-member had selected the wrong CSS that didn't have International dialing rights. I didn't have the correct picture yesterday. Today I simulated the issue myself & made a few test calls & all my doubts vanished. Thanks & have a nice weekend.

Regards,

Abhijit.

Rob Huffman Fri, 02/01/2008 - 06:25

Hi Abhijit,

Glad to be of some small help my friend! It is always hard to work on systems with multiple Admins. You are thinking one thing while the truth is opposite :)

I have found in working with my great team-mates over the years that the use of Templates does bring alot more consistancy when doing changes. But, of course, troubleshooting is also a great way to learn for all of us (it keeps the mind at work :)

Take care buddy!

Rob

UCBNOCWAN Fri, 02/01/2008 - 09:24

Thanks Rob,

It's really true, it was a good oppurtunity for me to learn the true impact of CSS which I have taken for granted all these years. Just shows IP Telephony is so vast & interesting. I rate your encouraging post 4 & for sharing your experience with your team mates. Have a nice weekend.

Regards,

Abhijit.

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