Sizing Cisco Callmanager Servers For Ipcc: Call Processing With Ipcc Enterprise
Sizing Cisco Callmanager Servers For Ipcc: Call Processing With Ipcc Enterprise
Sizing Cisco Callmanager Servers For Ipcc: Call Processing With Ipcc Enterprise
Determine customer call center application requirements (IP IVR, ISN, outbound, multi-channel, and so forth). Determine the types of call center resources and devices used in IPCC Enterprise (route points, CTI ports, and so forth):
Number of required IPCC Enterprise agents Number of required IP IVR CTI ports or ISN ports (or sessions) Number of CTI route points (ICM route points and IVR route points) Number of PSTN trunks Estimated busy hour call attempts (BHCA) for all agents and devices mentioned above (Inbound
or outbound?)
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Determine the required deployment model (single site, centralized, distributed, clustering over the WAN, or remote branches within centralized or distributed deployments). Determine the placement of solution components in the network (gateways, agents, ISN, and so forth). Determine the different types of call flows and call disposition, such as:
Simple call flow (IVR self-service or direct agent transfer without any IVR call treatment)
Simple call flows are those that do not involve multiple call handling (for example, IVR self-service, incoming calls from a gateway directly to a phone, internal calls, and so forth).
Complex call flow (IVR call treatment or database lookup prior to agent transfer, call
redirection to a route point, CTI route point, CTI ports, agent-to-agent transfer and conference, or consultation or conference from an agent to a skill group) Complex call flows are those that involve multiple call redirects and call handling of the original call (for example, incoming calls to central route points redirected to CTI route points and then to IP IVR for call treatment, then transferred or redirected to another target such as an agent). These multiple call processing segments of the original call consume more CPU resources compared to simple call handling.
A cluster may contain a mix of server platforms, but all servers in the cluster must run the same Cisco CallManager software release and service pack. The publisher server should be of equal or higher capability than the subscriber servers. (See Table 6-2.)
Devices (including phones, music on hold, route points, gateway ports, CTI ports, JTAPI Users, and CTI Manager) should never reside or be registered on the publisher. Any administrative work on Cisco CallManager will impact call processing and CTI Manager activities if there are any devices registered with the publisher. Do not use a publisher as a failover or backup call processing server unless you have fewer than 50 agent phones and the installation is not mission critical or is not a production environment. The Cisco MCS-7825H-3000 is the minimum server required. Any deviations will require review by Cisco Bid Assurance on a case-by-case basis. Any deployment with more than 50 agent phones requires a minimum of two subscriber servers and a combined TFTP and publisher. If you require more than one primary subscriber to support your configuration, then distribute all agents equally among the cluster nodes. This assumes BHCA is uniform across all agents (average BHCA processed is about the same on all nodes). Similarly, distribute all gateway ports and IP IVR CTI ports equally among the cluster nodes. If you require more than one ICM JTAPI user (CTI Manager) and more than one primary subscriber, then group and configure all devices monitored by the same ICM JTAPI User (third-party application provider), such as ICM route points and agent devices, in the same server if possible.
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Sizing Cisco CallManager Servers For IPCC IPCC Enterprise with Cisco CallManager Releases 3.1 and 3.2
If you have a mixed cluster with IPCC and general office IP phones, group and configure each type on a separate server if possible (unless you need only one subscriber server). For example, all IPCC agents and their associated devices and resources (gateway ports, CTI ports, and so forth) would be on one or more Cisco CallManager servers, and all general office IP phones and their associated devices (such as gateway ports) would be on other Cisco CallManager servers, as long as cluster capacity allows. In this case, the 1:1 redundancy scheme is strongly recommended. (See Call Processing Redundancy with IPCC, page 6-9, for details) Under normal circumstances, place all servers from the Cisco CallManager cluster within the same LAN or MAN. Cisco does not recommend placing all members of a cluster on the same VLAN or switch. If the cluster spans an IP WAN, you must follow the specific guidelines for clustering over the IP WAN as described in both the section on Clustering Over the WAN, page 2-15 in this guide, and the section on Clustering Over the IP WAN in the Cisco IP Telephony Solution Reference Network Design (SRND) guide, available at http://www.cisco.com/go/srnd
For additional Cisco CallManager clustering guidelines, refer to the Cisco IP Telephony Solution Reference Network Design (SRND) guide at http://www.cisco.com/go/srnd
Within a cluster, you may enable a maximum of 6 call processing servers (4 primary and 2 backup servers) with the Cisco CallManager Service. Other servers may be used for more dedicated functions such as Trivial File Transfer Protocol (TFTP), database publisher, music on hold, and so forth. You can configure a maximum of 800 Computer Telephony Integration (CTI) connections or associations per server, or a maximum of 3200 per cluster if they are equally balanced among the four primary servers. This maximum would include IPCC agent phones, IP IVR CTI ports, CTI route points, and other CTI devices. Each H.323 device can support up to 500 H.323 calls with Cisco CallManager Release 3.1 or 1000 calls with Cisco CallManager Release 3.2. The default trace setting for Cisco CallManager Release 3.1 or 3.2 is different than the setting for later releases (Cisco CallManager Release 3.3 and later) and typically has a lesser impact on disk I/O. When upgrading to Cisco CallManager Release 3.3 or later, ensure that the installed MCS-7800 Series server is able to handle the maximum rated agent capacity. Servers that do not have the capability to add the battery-backed write cache (BBWC) enabler kit typically are rated at half the capacity of the equivalent server with the BBWC installed. (This does not mean that you can double the agent capacity simply by installing the BBWC because the capacity might be limited by other server resources such as processor speed and memory. BBWC helps reduce disk I/O contention, thus allowing the CPU to process a higher transaction load.)
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Chapter 6 IPCC Enterprise with Cisco CallManager Releases 3.3 and Later
The default trace file location for the Cisco CallManager and signal distribution layer (SDL) is on the primary drive. This trace file should be redirected to the secondary F drive array, and the CTI default trace file location should be directed to the C drive array. This configuration will have the least impact on disk I/O resources.
Within a cluster, you may enable a maximum of 8 servers with the Cisco CallManager Service, including backup servers. Other (additional) servers may be used for more dedicated functions such as TFTP, publisher, music on hold, and so forth. You can configure a maximum of 800 CTI connections or associations per standard server that does not have battery-backed write cache (BBWC) installed (as defined in Table 6-2), or a maximum of 3200 per cluster, and a maximum of 2000 controlled devices per CTI application if they are equally balanced among all servers (Cisco MCS-7835 server required). You can configure a maximum of 2500 CTI connections or associations per MCS-7845H with battery-backed write cache (BBWC) or equivalent high-performance server (see Table 6-2), or a maximum 10,000 per cluster, and a maximum of 2500 controlled devices per CTI application if they are equally balanced among all servers. Again this maximum would include IPCC agent phones, IP IVR CTI ports, CTI route points, and other third-party application CTI devices configured in Cisco CallManager. Each Cisco CallManager cluster (four primary and four backup subscriber servers) can support up to 2,000 IPCC agents and no more than 60,000 BHCA. The BHCA would be spread equally among the eight call processing servers with 1:1 redundancy. (See Call Processing Redundancy with IPCC, page 6-9, for redundancy schemes.) Each of the eight Cisco CallManager servers (MCS-7845H High Performance Servers with BBWC installed) would support a maximum of 250 agents or 7,500 BHCA. In a failover scenario, the primary server would support a maximum of 500 agents and 15,000 BHCA. These capacities can vary, depending on your specific configuration (simple versus complex call flows), as determined by the Cisco CallManager Capacity Tool. (See Cisco CallManager Capacity Tool, page 6-5.)
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Sizing Cisco CallManager Servers For IPCC Cisco CallManager Capacity Tool
Note
If your system does not meet the guidelines in this document, or if you consider the system to be complex (IP Telephony and IPCC mixed with other applications), contact your Cisco Systems Engineer (SE) for proper sizing of the Cisco CallManager cluster.
Device or Port
IP Telephony Input
Average Busy Hour Traffic Utilization 0.15 0.8 0.3 0.3 0.3 0.8 0.15 0.8 0.8
IP phone Unity connection port CTI port Type #1 (simple call, redirect) CTI port Type #2 (transfer, conference) CTI route point Third-party controlled line Intercluster trunk gateways Intercluster trunks H323 client (phone) H323 gateways H323 gateway DS0s (T1 CAS, T1 PRI, E1 PRI, Analog) MGCP gateways
MGCP gateway DS0s (T1 CAS, T1 PRI, E1 PRI, Analog) 20 MoH (Music on Hold) stream (coresident, maximum of 20 streams) Transcoder MTP resource (hardware, coresident software, or standalone software) Conference resource (hardware, coresident software, or standalone software) Dial plan Directory numbers or lines 20 20 6
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Table 6-1
IPCC agents ISN (prompt and collect or queueing) ISN (self-service) CTI ports or IP IVR (prompt and collect or queueing) CTI ports or IP IVR (self-service) CTI route points H323 gateways H323 gateway DS0s (T1 CAS, T1 PRI, E1 PRI, Analog) MGCP gateways
30
0.8
30 30
0.8 0.8
20
0.8 0.8
MGCP gateway DS0s (T1 CAS, T1 PRI, E1 PRI, Analog) 20 % Agent-to-agent transfer % Agent conference
IPCC Outbound
IPCC outbound predictive/preview agents IPCC outbound direct preview agents IPCC outbound dialer ports IPCC outbound IVR ports H.323 gateways H.323 gateway DS0s (T1 CAS, T1 PRI, E1 PRI, analog) MGCP gateways MGCP gateway DS0s (T1 CAS, T1 PRI, E1 PRI, analog)
In addition to the device information, the Cisco CallManager Capacity Tool also requires information regarding the dial plan, such as route patterns and translation patterns. The IPCC input includes entries for agents (inbound and outbound), Internet Service Node (ISN) or IP IVR ports for gateway ports, and percent of total calls that are transferred and/or conferenced. When all the details have been entered, the Cisco CallManager Capacity Tool calculates how many servers of the desired server type are required, as well as the number of clusters if the required capacity exceeds a single cluster. At this time, the Cisco CallManager Capacity Tool is available to all Cisco employees and partners at http://www.cisco.com/partner/WWChannels/technologies/resources/CallManager/
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Sizing Cisco CallManager Servers For IPCC Supported Cisco CallManager Server Platforms for IPCC Enterprise
Characteristics
IPCC Enterprise Recommendation1 Up to a maximum of 100 agents (Not recommended for mission-critical call centers above 50 agents) Up to a maximum of 250 agents (Maximum of 125 agents without BBWC installed)
Single processor Single power supply (not hot-swap) Non-RAID hard disk (not hot-swap) Single processor Redundant power supplies (hot-swap) Redundant SCSI RAID hard disk array (hot-swap) Dual processors Redundant power supplies (hot-swap) Redundant SCSI RAID hard disk arrays
Recommended for all mission-critical contact centers up to a maximum of 500 agents (Maximum of 250 agents without BBWC installed)
1. Agent capacities are based on a maximum of 30 BHCA per agent in the busy hour.
The maximum number of IPCC Enterprise agents that a single Cisco CallManager server can support depends on the server platform, as indicated in Table 6-3.
Table 6-3 Maximum Number of IPCC Enterprise Agents per Cisco CallManager (Release 3.3 or Later) Server Platform
Cisco MCS-7845H-3000 (Dual Prestonia Xeon 3.06 GHz 500 or higher) 4 GB RAM HP DL380-G3 3.06 GHz 2-CPU 3 Cisco MCS-7845H-2400 (Dual Prestonia Xeon 2400 MHz) 4 GB RAM (With the addition of battery-backed write cache, BBWC, installed separately) HP DL380-G3 2400 MHz 2-CPU Cisco MCS-7845H-2400 (Dual Prestonia Xeon 2400 MHz) 4 GB RAM (Without BBWC) HP DL380-G3 2400 MHz 2-CPU Cisco MCS-7835H-3000 (Prestonia Xeon 3.06 GHz) 2 GB RAM (With the addition of battery-backed write cache, BBWC, installed separately) HP DL380-G3 3.06 GHz 1-CPU 250 250 500
Yes
Yes 5
Yes
Yes
Yes
No5
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Table 6-3
Maximum Number of IPCC Enterprise Agents per Cisco CallManager (Release 3.3 or Later) Server Platform
High-Performance Server No
Cisco MCS-7835H-3000 (Prestonia Xeon 3.06 GHz) 2 GB RAM (Without BBWC) HP DL380-G3 3.06 GHz 1-CPU Cisco MCS-7825H-3000 (Pentium 4, 3.06 GHz) 2 GB RAM HP DL320-G2 3.06 GHz6
100
No
No
1. For the latest information on server memory requirements, refer to Product Bulletin No. 2864, Physical Memory Recommendations for Cisco CallManager Version 4.0 and Later, available at http://www.cisco.com/en/US/products/sw/voicesw/ps556/prod_bulletin0900aecd80284099.html. 2. Agent capacities are based on a maximum of 30 BHCA per agent in the busy hour and failover scenario. 3. A high-availability server supports redundancy for both the power supplies and the hard disks. 4. This server has the battery-backed write cache kit (BBWC) installed. 5. This server does not have the battery-backed write cache kit (BBWC) installed. Without this kit, the capacity would be half the stated limit. The kit must be ordered and installed separately to achieve the maximum stated agent capacity. 6. The maximum number of IPCC agents supported on a single non-high-availability platform (such as the MCS-7825H) is 50 agents in a mission-critical call center. With a redundant configuration, this limit does not apply.
Agent capacities are based on Cisco CallManager Release 3.3 and later, in failover mode. The maximum number of IPCC agents is 500 with Cisco CallManager Release 3.3 or later, or 250 IPCC agents with Cisco CallManager Release 3.2 or earlier. A single non-high-availability platform supports a maximum of 50 IPCC agents. With a redundant server configuration, this limit does not apply. The Cisco MCS-7845I-3000 is not a supported MCS platform for Cisco CallManager. However, the IBM server equivalent (IBM x345, 3.06 GHz dual CPU) is supported for IPCC deployments as a software only-platform with OS 2000.2.6. The Cisco MCS-7815I-2000 server is a supported Cisco CallManager platform for Cisco IP Telephony deployments only. It is not supported with IPCC Enterprise deployments, but lab or demo setups can use this server. Newer MCS-7835H and MCS-7845H server platforms have the same capacities as shown in Table 6-3.
For the latest information on supported platforms and specific hardware configurations, refer to the online documentation at http://www.cisco.com/en/US/products/hw/voiceapp/ps378/prod_brochure_list.html The capacities outlined in this section provide a design guideline for ensuring an expected level of performance for normal operating configurations. Higher levels of performance can be achieved by disabling or reducing other functions that are not directly related to processing calls. Increasing some of these functions can also have an impact on the call processing capabilities of the system. Some of these functions include tracing, call detail recording, highly complex dial plans and call flows, and other services that are coresident on the server. Highly complex dial plans can include multiple line appearances, many partitions, calling search spaces, route patterns, translations, route groups, hunt groups, pickup groups, route lists, extensive use of Call Forward, coresident services, and other
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coresident applications. All of these functions can consume additional memory resources within the Cisco CallManager server. To improve performance, you can install additional certified memory in the server, up to the maximum supported for the particular platform. A Cisco CallManager cluster with a very large dial plan containing many gateways, route patterns, translation patterns, and partitions can take an extended amount of time to initialize when the Cisco CallManager Service is first started. If the system does not initialize within the default time, there are service parameters that can be increased to allow additional time for the configuration to initialize. For details on the service parameters, refer to the online help for Service Parameters in Cisco CallManager Administration.
2:1 For every two primary subscribers, there is one shared backup subscriber. 1:1 For every primary subscriber, there is a backup subscriber.
The 1:1 redundancy scheme allows upgrades with only the failover periods impacting the cluster. Cisco CallManager Release 3.3 and later supports up to eight subscribers (servers with the Cisco CallManager service enabled), so you may have as many as four primary and four backup subscribers in a cluster. The 1:1 redundancy scheme enables you to upgrade the cluster using the following method.
Step 1 Step 2 Step 3
Upgrade the publisher server. Upgrade dedicated TFTP and music on hold (MoH) servers. Upgrade all backup subscribers. This step will impact some users if 50/50 load balancing is implemented. During this step, the Cisco CallManager service is stopped in the backup subscriber, and the devices move to the primary subscriber. Fail-over the primary subscribers to their backups, and stop the Cisco CallManager service on the primaries. All users are on primaries and are moved to backup subscribers when the Cisco CallManager service is stopped. CTI Manager is also stopped, causing the Peripheral Gateway (PG) to switch sides and inducing a brief outage for agents on that particular node. Upgrade the primaries, and then re-enable the Cisco CallManager service.
Step 4
Step 5
With this upgrade method, there is no period (except for the failover period) when devices are registered to subscriber servers that are running different versions of the Cisco CallManager software. This factor can be important because the Intra-Cluster Communication Signaling (ICCS) protocol that communicates between subscribers can detect a different software version and shut down communications to that subscriber. This action could potentially partition a cluster for call processing, but SQL and LDAP replication would not be affected. The 2:1 redundancy scheme allows for fewer servers in a cluster, but it can potentially result in an outage during upgrades. This is not a recommended scheme for IPCC, although it is supported if it is a customer requirement and possible outage of call processing is not of concern to the customer.
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The 2:1 redundancy scheme enables you to upgrade the cluster using the following method. If the Cisco CallManager service does not run on the publisher database server, upgrade the servers in the following order:
Step 1 Step 2 Step 3
Upgrade the publisher database server. Upgrade the Cisco TFTP server if it exists separately from the publisher database server. Upgrade servers, one server at a time, that have only Cisco CallManager-related services (music on hold, Cisco IP Media Streaming Application, and so on) running on them. Make sure that you upgrade only one server at a time. Make sure that the Cisco CallManager service does not run on these servers. Upgrade each backup server, one server at a time.
Step 4
Note
Cisco does not recommend that you oversubscribe the backup server(s) during the upgrade. Cisco strongly recommends that you have no more than the maximum of 500 IPCC agents registered to the backup server during the upgrade. Cisco strongly recommends that you perform the upgrade during off-peak hours when low call volume occurs.
Step 5
Upgrade each primary server that has the Cisco CallManager service running on it. Remember to upgrade one server at a time. During the upgrade of the second primary subscriber, there will be some outage for users and agents subscribed on that server, until the server is upgraded. Similarly, when you upgrade the fourth primary subscriber, there will be some outage for users and agents subscribed on that server, until the server is upgraded.
Backup
M
M M
Backup Backup
M M
M M
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Figure 6-2
Primary Primary
Publisher and TFTP Server(s) MAX 1500 AGENTS Backup Backup Backup
M M
Publisher and TFTP Server(s) MAX 2000 AGENTS Backup Backup Backup Backup
M M
Figure 6-3
Primary Primary
Backup
M
M M
Backup
Backup
Primary Backup
M
M M
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Figure 6-4
1:1 IPCC Enterprise Redundancy with Cisco CallManager Release 3.3 or Later, with 50/50 Load Balancing (High-Performance Server with BBWC Installed)
500 IPCC AGENTS Publisher and TFTP Server(s) 1 to 250: Primary 251 to 500: Backup 251 to 500: Primary 1 to 250: Backup
1000 IPCC AGENTS Publisher and TFTP Server(s) 251 to 500 751 to 1000 1 to 250 501 to 750
2000 IPCC AGENTS Publisher and TP Server(s) 251 to 500 751 to 1000 1250 to 1500 1750 to 2000
M
1501 to 1750
Note
MCS-7845H-2.4 Advanced server does not come with BBWC installed; BBWC must be ordered separately.
Figure 6-5
1:1 Redundancy for Mixed Office and IPCC Phones with Cisco CallManager Release 3.3 or Later on MCS-7845H-3000 High-Performance Server with 50/50 Load Balancing
250 IPCC AGENTS AND 3750 PHONES Publisher and TFTP Server(s) IPCC Agents 250 Agents: Primary 3750 Phones: Backup Phones 3750 Phones: Primary 250 Agents: Backup
M
500 IPCC AGENTS AND 7500 PHONES Publisher and TFTP Server(s) IPCC Agents 251 to 500
M M
1000 IPCC AGENTS AND 15000 PHONES Publisher and TP Server(s) IPCC Agents
1 to 250
Phones
M
3751 to 7500
1 to 3750
Phones
M M M M
7501 to 11250
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Software release versions The type and quantity of devices registered, such as:
CTI ports Gateway ports Agent phones Route points CTI Manager
The load (BHCA) processed by these devices. As the call rate increases, more CPU resources are consumed on the Cisco CallManager server. Average call duration Longer average call duration means a lower busy-hour call completion rate, which lowers CPU usage. Special Cisco CallManager configurations and services such as:
MOH Tracing levels
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Application call flow complexity (See the definitions of simple and complex call flows in the section on Call Processing With IPCC Enterprise, page 6-1.)
IVR self-service Call treatment Routing to agents Transfers and conferences
CPU consumption varies by type of call flow. For simple call flows, the CPU consumption is moderate, but CPU consumption for complex call flows is much higher.
Tests conducted with a complex call flow (call treatment then transfer to agents) using IP IVR with H323 gateways show an increase in CPU usage compared to the same call flow using ISN (H.323 gateway). This difference is due to the fact that ISN does not require calls to be routed to Cisco CallManager before call treatment; instead, Cisco CallManager is involved only when calls are transferred to agents (simple call handling). The trade-off is that ISN gateways have increased performance demands. (See Sizing ISN Components, page 4-20, for more information). Similarly, complex call flows using IP IVR with Media Gateway Control Protocol (MGCP) gateways show an increase in CPU usage compared to the same call flow using ISN (H.323 gateway). This difference is due to the way ISN routes the calls (as described in the preceding paragraph) and to the fact that the H.323 gateway protocol uses more CPU resources than MGCP does. ISN configurations, simple call flow configurations, and a lower call arrival rate (BHCA) might be able to support more than 2,000 agents per Cisco CallManager cluster. Please consult with your Cisco Systems Engineer for proper sizing of your system requirements. Trace level enabled Cisco CallManager CPU resource consumption varies, depending on the trace level enabled. Changing the trace level from Default to Full on Cisco CallManager can increase CPU consumption significantly under high loads. (Changing the tracing level from Default to No tracing can decrease CPU consumption significantly at high loads, but this is not a recommended configuration and is not supported by Cisco Technical Assistance Center.) CPU consumption due to Default traces will vary based on load, Cisco CallManager release, applications installed, call flow complexity, and so forth.
Memory consumption and disk I/O resources (battery-backed write cache) Phone authentication and encryption
It is important to balance all resources equally as much as possible if you are using more than one primary Cisco CallManager server. This balancing of resources will prevent overloading one server to benefit the others.
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