Cisco OL-12456-01 User Manual
CHA PTER
7
High Latency and Low Bandwidth
Interconnection
Cisco IPICS provides support for environments that include high latency and low or variable bandwidth
links, such as satellite links. In these types of environments, connectivity may become unstable because
of the geographical location of the user, weather elements, and other interferences. In this release, Cisco
IPICS compensates for these dynamically variable bandwidth scenarios and enhances its support for
mobile operations.
Cisco IPICS supports the following deployment scenarios:
• Central site server solution—Supports a Cisco IPICS server that is installed at a central site and a
distributed router media service (RMS) and end-user client components that are installed at a remote
site.
• Remote locations solution—Supports deployment of the Cisco IPICS server, RMS, and end-user
clients at two remote sites that are connected by M1:U12:M2 tunnels.
• Remote PMC solution—Supports a Cisco IPICS server and a distributed RMS at a central site and
end-user PMC clients at a remote site.
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Note Note: With this deployment scenario, remote PMC clients must be configured to use the
“Optimize for low bandwidth” setting in the PMC Settings > Channels menu. For information
about how to configure the PMC for use in this deployment scenario, refer to the “Configuring
the PMC Application” chapter in Cisco IPICS PMC Installation and User Guide, Release 2.0(1).
The M1:U12:M2 tunneling technology enables these deployment scenarios. For more information about
these deployment scenarios, see the “Supported Deployment Solutions” section on page 7-2.
This chapter includes these topics:
• Supported Deployment Solutions, page 7-2
• Requirements and Support Information, page 7-4
• Performing Additional Configurations on the Cisco IPICS Server, page 7-5
• Performance Guidelines, page 7-8
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Supported Deployment Solutions
Supported Deployment Solutions
Cisco IPICS enhancements include support for the deployment solutions that are described in the
following topics:
• Central Site Server Solution, page 7-2
• Remote Locations Solution, page 7-3
• M1:U12:M2 Configuration Examples, page 7-3
Central Site Server Solution
In the central site server solution, the Cisco IPICS server is located in a central site and an RMS is
distributed with the PMC and other end-user clients in a remote site that is connected via a high latency,
low bandwidth connection. In this situation, the Cisco IPICS server must control the distributed RMS,
and the dispatcher at the central site needs to be able to communicate with remote PMC clients in the
field.
This deployment solution provides the ability to remotely control the RMS over the high latency, low
bandwidth links. Communications are enabled by the support of an M1:U12:M2 connection trunk
between the RMS in the central site and a remotely-located RMS.
The M1:U12:M2 connection trunk also provides the capability for IP phone XML services and PMC
clients to communicate between sites.
Chapter 7 High Latency and Low Bandwidth Interconnection
Note M1:U12:M2 (Multicast1:Unicast1-Unicast2:Multicast2) provides a unicast connection path between
two multicast islands. An M1:U12:M2 connection trunk maps multicast to unicast on one side of the
network, provides transport over the unicast wide area network (WAN) as a unicast Voice over IP (VoIP)
call, and then converts it back to multicast on the other side of the connection, such that multicast 1 is
connected to multicast 2 via a unicast connection between 1 and 2 M1:U12:M2 transports only the
multicast traffic that is configured on the trunk as contrasted to Generic Routing Encapsulation (GRE)
tunnels, which transport all multicast traffic.
See the “Performing Additional Configurations on the Cisco IPICS Server” section on page 7-5 for additional
configurations that apply to this deployment.
Caveats
Be aware of the following caveats when you use the central site server deployment solution:
• Because all RMS commands flow over the high latency, low bandwidth link, this solution results in
reduced throughput and slower response time.
• Some RMS-related operations may take over 3 minutes. Throughput considerations are based on
factors such as the number of active channels that are included in the VTGs, the number of DS0s
that are being used on the RMS, and the number of PMC users that are communicating between the
sites. This limitation is due to inherent Transmission Control Protocol/Internet Protocol (TCP/IP)
limitations over high latency, low bandwidth links. For information about RMS configuration
updates when you use this deployment solution, see the “Updating the RMS Configuration” section
on page 7-5.
• If you do not have a local router installed at the central site, you may need to configure Address
Resolution Protocol (ARP) commands to increase the ARP timer so that the RMS remains
reachable. For more information, see the “Adjusting ARP Commands” section on page 7-6.
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Chapter 7 High Latency and Low Bandwidth Interconnection
• The RMS and the Cisco IPICS server automatic synchronization mechanism must be disabled in this
scenario. Therefore, you must manually synchronize these components. For more information about
the manual configurations that you must perform, see the “Disabling the RMS Comparator” section
on page 7-6 and the “Merging the Configuration” section on page 7-6.
• To conserve bandwidth, you must disable the PMC upload log frequency. For more information, see
the “Disabling the PMC Upload Activity Log Frequency” section on page 7-7.
• Although the M1:U12:M2 connection trunk consumes dedicated bandwidth between the central site
and the remote site, it does provide for bandwidth optimization by allowing transcoding to the G.729
codec.
• This deployment solution does not support the use of IP phone XML services at the remote
locations. IP phone XML services are available only at the central site.
• There is no support for direct PMC access to the remote locations. The PMC clients can be at the
remote site or the central site but they cannot remotely connect across sites.
Remote Locations Solution
In the remote locations solution, a Cisco IPICS server, RMS, PMC, and other end-user clients are located
at two remote sites. High latency, low bandwidth links that connect these remote sites enable
communications flow.
Supported Deployment Solutions
This deployment enables communications by the use of fixed M1:U12:M2 tunnels that are configured
between the channels that are hosted on each RMS at each remote site, such that each channel is mirrored
on the other sites.
The M1:U12:M2 connection trunk also provides the capability for IP phone XML services and PMC
clients to communicate between sites.
See the “Performing Additional Configurations on the Cisco IPICS Server” section on page 7-5 for
additional configurations that apply to this deployment.
Caveats
Be aware of the following caveats when you use the remote locations deployment solution:
• The M1:U12:M2 connection trunks consume dedicated bandwidth between the remote sites,
however bandwidth optimization is enabled by allowing transcoding to the G.729 codec.
• If you use several Cisco IPICS servers that each control their own RMS, care must be taken not to
duplicate VTGs when defining channels. Because each channel is mirrored on the other remote site,
audio loops can occur between the sites when you use the same VTGs at each site.
• This deployment provides support for IP hone XML services at either the central site or the remote
sites. The IP phone XML services must be local to the site where they are deployed.
• There is no support for direct PMC access to the remote locations. The PMC clients can be at the
remote site(s) or the central site, but they cannot remotely connect across the sites (they must be
local to the site where they are deployed).
M1:U12:M2 Configuration Examples
The following tables provide configuration examples for the multicast portion of the M1:U12:M2
connection trunks.
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