The Enhanced Location Call Admission Control (CAC) feature improves the Location CAC mechanism to support complex network, multi-tier, multi-hop topology. This feature supports Location CAC within a cluster and among multiple clusters and allows end to end bandwidth deduction. This enhancement to the CAC feature creates a much more flexible and dynamic system for the management of bandwidth.
The enhanced CAC feature provides a new service, called Location Bandwidth Manager (LBM). The LBM service can be configured to run on every node or selected nodes of a Cisco Unified Communications Manager (Unified CM) server.
Terminology for Enhanced Location Call Admission Control:
- Link: Links interconnect locations and are used to define the bandwidth available between locations.
- Weight: The relative priority of a link in forming the effective path between any pairs of locations. Weights are used on links to provide a "cost" to the "effective path". The effective path has the least cumulative weight of all other paths. Weights are pertinent only when there is more than 1 path between any 2 locations.
- Locations: A Location represents a LAN. It could contain endpoints or simply serve as a transit location between links for WAN network modeling
- Bandwidth Allocation: The amount of bandwidth allocated in the model for each type of traffic: audio, video, and immersive video (Telepresence).
- Path: A sequence of links and intermediate locations connecting a pair of end locations. Only one effective path between a pair of end locations is used
- Locations Bandwidth Manager: A service that assembles a network model from configured location and link data in one or more clusters, determines the effective paths between pairs of locations, determines whether to admit calls between a pair of locations based on the availability of bandwidth for each type of call, and deducts (reserves) bandwidth for the duration of each call that is admitted.
- Locations Bandwidth Manager Hub: An LBM service that has been designated to participate directly in inter-cluster replication of fixed and dynamic data. LBMs assigned an LBM hub group discover each other through their common connections and form a fully meshed replication network. Other LBM services in a cluster with an LBM hub participate indirectly in inter-cluster replication through the LBM hubs in their cluster.
- Shadow location: SIP Inter-cluster Trunks must be assigned to the Shadow location to enable proper inter-cluster operation of this feature. SIP trunks to devices with a specific location, such as SIP Gateways, may be assigned to ordinary locations. A Shadow location is a special location that has no links to other locations and no bandwidth allocations.
From HQ-CUCM, under the Cisco Unified Serviceability, activate the Location Bandwidth Manager (LBM) service.
Go the Region configuration page.
Create a region named Region-US. Click Save.
In the Modify Relationship to other Regions section, select the Region-US and in the Maximum Audio Bit Rate section, choose the G711 codec. Click Save.
Create a region named Region-TO-GE. Click Save.
Under the Region-US, In the Modify Relationship to other Regions section, select the Region-TO-GE and in the Maximum Audio Bit Rate section, choose the G729 codec. Click Save.
Create a location named LOC-US.
Create a location named LOC-TO-GE.
Remove the Hub_None location and click Add.
Allow one (1) G729 voice call from this location to LOC-US location. Set the Audio Bandwidth to 24 Kbps. Click Save.
Create a Device Pool named DP-US, in the Roaming Sensitive Settings, select the Region-US in the Region section. Select the LOC-US in the Location section.
Create a Device Pool named DP-TO-GE, in the Roaming Sensitive Settings, select the Region-TO-GE in the Region section. Select the LOC-TO-GE in the Location section.
Edit the US Phone 1 and US Phone 2, assign the device pool DP-US.
Create an LBM group.
Enter the name LBM-US-GROUP, from the Location Bandwidth Manager Group Members section, select the HQ-CUCM 10.1.5.15 as Active Member. Click Save.
Configure LBM Hub Group to allow Hub 10.1.5.15 to discover LBM server 10.1.5.20 in remote GE cluster and establish communication.
Enter the name LBM-Intercluster-US, under the Bootstrap Servers section, configure the IP address 10.1.5.20 which is the remote Hub BB-CUCM, under the Role Assignment select the local server 10.1.5.15 and move it to the LBM Services Assigned to Hub Role. Click Save.
Ensure that the LBM intercluster replication group is applied to LBM server 10.1.5.15 that should act as LBM hub.
Go to the Trunk configuration and edit the SIP trunk Trunk-SIP-To-BB that points to 10.1.5.20.
Assign the SIP trunk to the Shadow location and select the Device Pool DP-TO-GE.
Shadow location is already running on CUCM, by assigning the Shadow location this SIP trunk can be used for Enhanced-CAC, to pass information in the sip invite when the call is setup.
In the SIP Invite header, there is CALL-INFO, this field contains information about locations, class of traffic, desktop video immersive video, what is the class of this traffic.
Repeat the same configuration steps for BB-CUCM 10.1.5.20.
Under the Cisco Unified Serviceability, activate the Location Bandwidth Manager (LBM) service.
Create a region named Region-GE and create another region named Region-TO-US.
Under the Region-GE, In the Modify Relationship to other Regions section, select the Region-TO-US and in the Maximum Audio Bit Rate section, choose the G729 codec.
Create a location named LOC-GE and create another location named LOC-TO-US.
Allow one (1) G729 voice call from LOC-GE location to LOC-TO-US location. Set the Audio Bandwidth to 24 Kbps.
Create a Device Pool named DP-GE, in the Roaming Sensitive Settings, select the Region-GE in the Region section. Select the LOC-GE in the Location section.
Create a Device Pool named DP-TO-US, in the Roaming Sensitive Settings, select the Region-TO-US in the Region section. Select the LOC-TO-US in the Location section.
Edit the GE Phone 1 and GE Phone 2, assign the device pool DP-GE.
Create an LBM group.
Enter the name LBM-GE-GROUP, from the Location Bandwidth Manager Group Members section, select the BB-CUCM 10.1.5.20 as Active Member.
Configure LBM Hub Group to allow Hub 10.1.5.20 to discover LBM server 10.1.5.15 in remote US cluster and establish communication.
Enter the name LBM-Intercluster-GE, under the Bootstrap Servers section, configure the IP address 10.1.5.15 which is the remote Hub HQ-CUCM, under the Role Assignment select the local server 10.1.5.20 and move it to the LBM Services Assigned to Hub Role.
Assign the SIP trunk Trunk-sip-to-HQ to the Shadow location and select the Device Pool DP-TO-US.
From the BB-CUCM, in Cisco Unified Serviceability, choose Tools > Locations > Topology and generate a list of known locations and links. You will see that the locations LOC-US and LOC-TO-GE are discovered and the max audio bandwidth between these locations is 24 and the weight is 50.
After discovering the locations, the Server calculates the effective path between the location based on the cumulative weight values defined in each link.
Choose Tools > Locations > Effective Path to see the effective path between on both HQ-CUCM and BB-CUCM respectively as shown below.
To demystify the concept of Enhanced-CAC, Locations represents a LAN, Links interconnect Locations and are used to define bandwidth available. Links logically represent the WAN link.
Weights are used on links to provide a cost to the effective path.
CUCM does the calculations and the least cost path/effective path is chosen. When we say CHOSEN, this means this is the path the CUCM will track, not to route CALL. The routing of voice traffic is done by the routing protocol.
LBM actively tracks bandwidth accross any link that the network model indicates from originating Location to terminatin location. If a G729 call is placed between locations separated by multiple links, the bandwidth 24kbps is deducted from each link, this is the key function of Enhanced-CAC, this is why the E-CAC support Multi-hop Topology while traditional CAC does not.
