Cisco Cisco IOS XE 3.13S
Services and Components
The variety of radio systems, desired participants, and operational needs of an organization cannot be satisfied by one Land Mobile
Radio (LMR) over IP architecture. So, instead of having an omnibus architecture, LMR over IP is broken down into a series of
services. Some of these services are implemented by means of the Cisco gateway routers running Cisco IOS software with the LMR
over IP feature set. Some services employ Cisco IP telephony equipment such as Cisco IP Phones and Cisco CallManager.
Radio (LMR) over IP architecture. So, instead of having an omnibus architecture, LMR over IP is broken down into a series of
services. Some of these services are implemented by means of the Cisco gateway routers running Cisco IOS software with the LMR
over IP feature set. Some services employ Cisco IP telephony equipment such as Cisco IP Phones and Cisco CallManager.
The following sections outline these LMR over IP services, providing a description of how and when they may be used to achieve a
more efficient, elegant, or scalable solution for LMR needs. It is important to understand that these tools are not exclusive of each
other. In many cases they can be quite complementary.
more efficient, elegant, or scalable solution for LMR needs. It is important to understand that these tools are not exclusive of each
other. In many cases they can be quite complementary.
Interoperability—The Radio Interface Adaption Layer
The foundation on which all LMR services are built is the interface joining the LMR radio systems to the IP network. The key to
implementing all these other services is to adapt the disparate LMR endpoints to a common standard. The radio systems are connected
through available wired connection points and not through their air interface. The radios are connected to the LMR-enabled Cisco
gateway routers through either an analog ear and mouth (E&M) interface or a digital T1 interface. LMR-specific enhancements to
Cisco IOS software provide greater flexibility in controlling audio levels, tuning voice activity detection (VAD), and improving the
ability of the router to interact with those radios that employ physical signaling. For those radio systems that utilize in-band tones for
signaling, additional hardware such as third-party tone remote units are required to adapt the radio to the IP environment.
implementing all these other services is to adapt the disparate LMR endpoints to a common standard. The radio systems are connected
through available wired connection points and not through their air interface. The radios are connected to the LMR-enabled Cisco
gateway routers through either an analog ear and mouth (E&M) interface or a digital T1 interface. LMR-specific enhancements to
Cisco IOS software provide greater flexibility in controlling audio levels, tuning voice activity detection (VAD), and improving the
ability of the router to interact with those radios that employ physical signaling. For those radio systems that utilize in-band tones for
signaling, additional hardware such as third-party tone remote units are required to adapt the radio to the IP environment.
With all participants using the same communications structure, any-to-any communication is now possible. Tone controlled systems
can communicate with systems using other tone schemes, or systems using physical signaling. Organizations can merge different
radio systems onto one common backbone, and they are freed from being tied down to one particular vendor or solution for their
radio needs.
can communicate with systems using other tone schemes, or systems using physical signaling. Organizations can merge different
radio systems onto one common backbone, and they are freed from being tied down to one particular vendor or solution for their
radio needs.
Transport
Once the radio system is connected to the network, the audio transmission needs to be sent to and from other endpoints. These three
mechanisms for accomplishing this task are discussed in the following sections:
mechanisms for accomplishing this task are discussed in the following sections:
Unicast Connection Trunk (Leased Line Replacement)
In LMR deployments topography, distance or other environmental factors can limit the coverage of the network. In some situations,
leased lines or other dedicated point-to-point transmission facilities are used to connect geographically remote devices. By using a
unicast connection trunk configuration on the LMR gateway, organizations can leverage standard IP connectivity over either the
public Internet, or a private network to backhaul their LMR traffic and provide data connectivity at these remote sites. In this manner,
the organization can achieve cost savings through either reduced facility charges or a reduction in the number of required connections
at the site.
In LMR deployments topography, distance or other environmental factors can limit the coverage of the network. In some situations,
leased lines or other dedicated point-to-point transmission facilities are used to connect geographically remote devices. By using a
unicast connection trunk configuration on the LMR gateway, organizations can leverage standard IP connectivity over either the
public Internet, or a private network to backhaul their LMR traffic and provide data connectivity at these remote sites. In this manner,
the organization can achieve cost savings through either reduced facility charges or a reduction in the number of required connections
at the site.
The unicast connection trunk service on the LMR gateway provides a permanent point-to-point connection between two voice
endpoints. It uses standard H.323 signaling to establish the VoIP circuit between the gateways. This circuit is capable of not only
sending audio information using standard Real-Time Transport Protocol (RTP) datagrams, but of physical lead state signaling as
well.
endpoints. It uses standard H.323 signaling to establish the VoIP circuit between the gateways. This circuit is capable of not only
sending audio information using standard Real-Time Transport Protocol (RTP) datagrams, but of physical lead state signaling as
well.
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