Enhanced Locations Call Admission Control Overview
Enhanced Locations Call Admission Control (CAC) lets you regulate audio quality and video availability over complex WAN topologies and intercluster networks. This includes multi-tier and multi-hop networks.
You can create a model of the complete network topology, indicating the different Locations (LANs) and WAN links that connect those locations. For each location and WAN link, assign bandwidth limits that represent the total bandwidth that is available for all calls over that link at one time. If bandwidth is not available for a particular call, the call is rejected with a busy signal. This prevents audio and video quality from degrading as a result of a WAN link becoming oversubscribed.
The intercluster replication functionality of the Location Bandwidth Manger (LBM) Replication Group lets you replicate your location configuration across an intercluster network, thereby making it easier to manage in large intercluster networks.
Enhanced Locations CAC Components
This feature uses the following components:
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Locations—A Location represents a LAN. It could contain endpoints or simply serve as a transit location between links for WAN network modeling. Cisco Unified Communications Manager supports up to 2000 locations.
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Links—The connection between two locations. When configuring this feature, you assign bandwidth allocations and weights for each link.
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Weight—The relative priority of the link in forming the effective path between any pairs of locations. Weights are used only when multiple paths exist between two locations. Weights are used to calculate the effective path (the path with the least cumulative weight).
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Bandwidth Allocations—The total bandwidth allocated for a particular type of traffic (audio, desktop video, immersive video) over a specific link. Bandwidth can also be allocated for intralocation calls (the default setting is Unlimited).
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Location Bandwidth Manager (LBM)—A feature service that must be activated in Cisco Unified Serviceability for Enhanced Locations CAC to work. This service assembles the network model and computes the effective path between locations by adding the weight of all links and locations between the source and destination, and choosing the path with the least cumulative weight.
Locations Relationship to Regions
The Locations configuration of Enhanced Locations Call Admission Control works with Regions to manage bandwidth for calls:
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The bandwidth allocations within the Region Configuration assigns the total amount of bandwidth that the endpoints in a call between two regions can use.
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The bandwidth allocations within Locations Configuration assigns the total amount of bandwidth that all calls between those locations can use. For an individual call, the bandwidth within the Regions Configuration is deducted from the amount of bandwidth that the location configuration makes available. For example, if the Locations configuration specifies that 160 kb/s of bandwidth is available over a particular link, that link can support two G.711 calls at 80 kb/s each simultaneously.
Note |
Do not change the Location Bandwidth Manager bandwidth or link configurations during production hours as that could unecessarily spike CPU utilization on the server. |
Cisco Unified Communications Manger supports up to 2,000 locations and 2,000 regions per cluster.
Intercluster LBM Replication
The Intercluster Replication capability of the Location Bandwidth Manager Hub Group lets you replicate your locations and link assignments across the larger intercluster network. You can assign LBMs to the LBM Hub role, which lets them actively replicate locations and link information across a meshed intercluter network. LBM hubs discover each other through their common connections and form a fully-meshed replication network. LBMs that are assigned a spoke role participate indirectly in intercluster replication through the LBM hubs in their cluster.
Intercluster Topology Management
There are multiple ways to configure and manage your intercluster network. The following table summarizes two approaches for configuring and managing the intercluster topology:
Design Approach |
Description |
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Location and Link Management |
Use a single cluster to configure and manage bandwidth allocations for all links across the intercluster network. This approach simplifies the configuration overhead, particularly in deployments with many common locations. The intercluster configuration approach is as follows: In the management cluster, configure all locations and links (including bandwidth allocations and weights) for the entire topology. This information will be replicated to the intercluster network. For the other clusters in the topology:
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Intercluster Enhanced Locations CAC |
With this approach:
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