License usage within a cluster
Any traversal or non-traversal call licenses that have been installed on a cluster peer are available for use by
any peer in the cluster. Usage is limited to the maximum physical capacity of each VCS unit:
Large VM servers
VCS appliances (or equivalent VM)
Traversal calls
500
150
Non-traversal calls
750
750
Registrations
5000
2500
TURN relays *
6000
1800
Table 3: Maximum physical capacity per peer
* On a Large VM, the total TURN capacity of 6000 relays is spread evenly across 6 ports; each port is limited
to handling 1000 relays. On VCS appliances (or equivalent VM), there is a single TURN port that handles up
to 1800 relays.
Note that each VCS comes pre-installed with 2,500 registration licenses, and that registration and
TURN relay licenses are not shared across a cluster.
If two endpoints are registered to different cluster peers, and a SIP call is made between them, two non-
traversal licenses are used. If the call is made over H.323, only one non-traversal license is used.
You can cluster up to 6 VCS systems to increase capacity by a maximum factor of 4 (see
Performance
capabilities [p.356]
for more information).
If a cluster peer becomes unavailable, the shareable licenses installed on that peer remain available to the
rest of the cluster peers for two weeks from the time the cluster lost contact with the peer. This will maintain
the overall license capacity of the cluster — however, note that each peer is still limited by its physical
capacity as listed above. After this two week period, the licenses associated with the unavailable peer are
removed from the cluster. To maintain the same capacity for your cluster, you should ensure that either the
problem with the peer is resolved or new option keys are installed on another peer in the cluster.
Note that you are also limited to the number of call license option keys that can be installed (purchased) per
VCS peer as follows:
Large VM servers
VCS appliances (or equivalent VM)
Traversal calls
500
100
Non-traversal calls
500
500
TURN relays
6000
1800
Table 4: Maximum call license option keys that can be installed (purchased) per peer
You can see a summary of all of the call, registration and TURN relay licenses installed on each cluster peer
by going to the
Option keys
page and scrolling down to the
Current licenses
section.
Capacity alarms are raised if either of the following usage thresholds are reached:
n
the number of concurrent traversal/non-traversal calls reaches 90% of the capacity of the cluster
n
the number of concurrent traversal/non-traversal calls on any one unit reaches 90% of the physical
capacity of the unit
Cisco VCS Administrator Guide (X8.1.1)
Page 160 of 507
Clustering and peers
License usage within a cluster