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Trunks and Device Pools

I'm in a CIPT class and I'm confused about something. Why are trunks assigned to device pools? I understand (mostly) the relationship between phones and device pools, but what function do device pools perform in relation to trunks?

Thanks!

John

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Trunks and Device Pools

Hi John,

Remember, a device pool is a collection of specific properties to be applied to members of that device pool. It is effectively a shortcut to quickly configure devices with certain similar properties.

Stop and consider the properties in the device pool.

Device Pool Name*

Cisco CallManager Group*

Date/Time Group*

Region*

Softkey Template*

SRST Reference*

Calling Search Space for Auto-registration

Media Resource Group List

Network Hold MOH Audio Source

User Hold MOH Audio Source

User Locale

Device Pool Name* - Is descriptive for human use.

Cisco CallManager Group* - specifies which callmanager servers are involved with/utilized by the device assigned to the device pool. Phones will register with these members. And GK controlled trunks will use these servers as H323 endpoints to register with a GK. Also can be used to specify which CCM servers act as local endpoints for non-GK controlled trunks. Essentially provides redundancy for all CCM controlled devices. And in the case of trunks, it provides call processing load sharing across CCM servers.

Date/Time Group*

Obvious with phones and servers, but also can be used to sync describe the timezone assumptions for gatekeepers or other CCM clusters.

Region*

Specify the codec to be used for calls across the trunk.

Softkey Template* - not used for trunks

SRST Reference* - not used for trunks

Calling Search Space for Auto-registration - not used for trunks

Media Resource Group List - media resources available for calls across the trunk.

Network Hold MOH Audio Source - for calls across the trunk

User Hold MOH Audio Source - for calls across the trunk

User Locale - Language for text signalling across the trunk

Let me know if this helps by rating the post.

Michael

5 REPLIES

Re: Trunks and Device Pools

John,

Trunks use device pools to obtain a list of Callmanagers to distribute calls. See the following quote from CCM help.

"For trunks, device pools specify a list of Cisco CallManagers that the trunk uses to distribute the call load dynamically.

Note : Calls that are initiated from a phone that is registered to a Cisco CallManager that does not belong to the trunk's device pool use different Cisco CallManagers of this device pool for different outgoing calls. Selection of Cisco CallManager nodes occurs in a random order.

A call that is initiated from a phone that is registered to a Cisco CallManager that does belong to the trunk's device pool uses the same Cisco CallManager node for outgoing calls if the Cisco CallManager is up and running."

Hope this helps. If so, please rate the post.

Brandon

New Member

Re: Trunks and Device Pools

I had already read that text but it didn't make sense to me. Here's what I think it means. Please let me know if I have this wrong.

Just as an IP phone or gateway must register with a CallManager server, so must a trunk. Some server must be responsible for handling the trunk. A device pool has a CallManager group associated with it. This allows us to point different trunks to different CallManagers to spread out the processing load.

Is that correct?

Re: Trunks and Device Pools

The trunk does not register with a Callmanager like a phone. It does use the Callmanager for processing. Consider the following example:

Callmanager Group Group1

CCM1

CCM2

CCM3

Callmanager Group Group2

CCM4

CCM5

CCM6

Device Pool DP1

Callmanager Group - Group1

Device Pool DP2

Callmanager Group - Group2

Phone1

Device Pool - DP1

Trunk1

Device Pool - DP2

If Phone1 is registered to CCM1 and makes a call that goes to Trunk1, one of the Callmanger's in Trunk1's device pool (CCM4, CCM5, CCM6) will be randomly chosen to handle call processing.

If, on the other hand, Phone1 has DP2, is registered to CCM4 and makes a call that goes to Trunk1, CCM4 will always be used for call processing because Phone1 is registered to a Callmanager that belongs to the trunk's device pool.

Brandon

Re: Trunks and Device Pools

Hi John,

Remember, a device pool is a collection of specific properties to be applied to members of that device pool. It is effectively a shortcut to quickly configure devices with certain similar properties.

Stop and consider the properties in the device pool.

Device Pool Name*

Cisco CallManager Group*

Date/Time Group*

Region*

Softkey Template*

SRST Reference*

Calling Search Space for Auto-registration

Media Resource Group List

Network Hold MOH Audio Source

User Hold MOH Audio Source

User Locale

Device Pool Name* - Is descriptive for human use.

Cisco CallManager Group* - specifies which callmanager servers are involved with/utilized by the device assigned to the device pool. Phones will register with these members. And GK controlled trunks will use these servers as H323 endpoints to register with a GK. Also can be used to specify which CCM servers act as local endpoints for non-GK controlled trunks. Essentially provides redundancy for all CCM controlled devices. And in the case of trunks, it provides call processing load sharing across CCM servers.

Date/Time Group*

Obvious with phones and servers, but also can be used to sync describe the timezone assumptions for gatekeepers or other CCM clusters.

Region*

Specify the codec to be used for calls across the trunk.

Softkey Template* - not used for trunks

SRST Reference* - not used for trunks

Calling Search Space for Auto-registration - not used for trunks

Media Resource Group List - media resources available for calls across the trunk.

Network Hold MOH Audio Source - for calls across the trunk

User Hold MOH Audio Source - for calls across the trunk

User Locale - Language for text signalling across the trunk

Let me know if this helps by rating the post.

Michael

New Member

Re: Trunks and Device Pools

Thanks for the excellent reply! You simply wouldn't believe all the ways that our instructor sucks. He really doesn't know squat. Everyone in the class is going to demand a refund from the training company.

Thanks again!

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