Chapter

Frame Relay Service Modules (FRSMs)

An application of a STUN connection is shown in Figure 4-5.An SNA/SDLC device is connected to a FRASM port using SDLC protocol. The traffic is first converted to Frame Relay and then to ATM cells for transmission over the network. At the other end, the traffic is first converted back to Frame Relay and the SDLC traffic is then extracted for transmission to a front-end communication processor and then to the IBM mainframe.

Figure 4-5 Using FRASM for a STUN Connection

Remote SDLC

End User Device

SDLC

FRASM

MGX 8220

ATM network

Frame Relay

over ATM

MGX 8220

FRASM

SDLC

Front-end

Processor

NCP1

Mainframe

VTAM1

11760

Using STUN, the FRASM supports

•Point-to-point SDLC lines.

•Multidropped SDLC devices over a single logical port. These devices can be assigned to different connections.

•Multiple logical connections over a single logical port.

•Virtual multidrop in which SDLC devices attached to FRASM modules on different MGX 8220 shelves can be configured to appear as multidropped devices on a single multidrop line.

BSTUN Connections

BSTUN, short for Block Serial TUNnel, is an IBM technique for transmitting bisync traffic over Frame Relay networks by encapsulating the bisync frames within Frame Relay frames using the protocol of RFC 1490.

There are two methods.

1.passthrough (or transparent)

The passthrough method encapsulates the entire bisync data stream including data and control fields for transmission over the Frame Relay network. In this method, the Frame Relay network is entirely transparent to the Bisync network. Passthrough mode is supported for 2780, 3780, and 3270 IBM devices.

2.local acknowledgment

The local acknowledgment method terminates the Bisync traffic at the Frame Relay network interface and encapsulates data only. The Bisync frames are then reconstructed at the other. Local acknowledgment mode is supported for 3270 devices.

For both methods, Bisync traffic received by the FRASM is converted first to a Frame Relay format and is then further converted into cells for transmission over an ATM network, the process is then performed in reverse order at the other end.

BTUN can also be used for a transparent text mode which permits the unrestricted coding of data (for example, binary, floating point, and so forth).

BSTUN is used where the requirements call for Bisync in and Bisync out with the intervening Frame Relay and ATM segments being used merely to transport the Bisync traffic.

 

Cisco MGX 8220 Installation and Configuration

4-12

Release 5.0, Part Number 78-6430-03 Rev. D0, November 2003

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Cisco Systems MGX 8220 manual Bstun Connections, Using Frasm for a Stun Connection
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MGX 8220 specifications

The Cisco Systems MGX 8220 is a versatile, high-performance media gateway that has become an integral component in the telecommunications infrastructure. Designed to facilitate the transition from traditional circuit-switched networks to advanced packet-switched environments, the MGX 8220 supports a wide array of voice, video, and data services, making it an essential tool for service providers and enterprises seeking to enhance their network capabilities.

One of the key features of the MGX 8220 is its robust signaling and media processing capabilities. Equipped with support for both Voice over IP (VoIP) and traditional telephony protocols, this gateway enables seamless integration of different communication formats. It boasts a modular architecture, which allows for the addition or removal of various line cards to meet changing demands and technology advancements. This modularity provides operators with the flexibility to scale their services without significant overhauls to their existing infrastructure.

The MGX 8220 is capable of delivering high-density media handling for a multitude of services. With its support for ATM and IP networks, the gateway can handle TDM (Time-Division Multiplexing) to packet voice conversions efficiently. It is designed to optimize network resources by dynamically allocating bandwidth based on traffic requirements, thus ensuring efficient use of network resources and improved performance.

Another significant characteristic of the MGX 8220 is its enhanced quality of service (QoS) features. This capability ensures that voice and video traffic is prioritized appropriately, minimizing latency and jitter while maximizing overall call quality. By employing sophisticated traffic management techniques, the MGX 8220 can deliver a superior user experience, which is critical for any service provider aiming to offer competitive communication solutions.

Furthermore, the gateway includes built-in security features to protect against unauthorized access and ensure the integrity of sensitive data. This includes encryption for voice and video transmission, as well as support for secure signaling protocols.

Overall, the Cisco Systems MGX 8220 stands out as a comprehensive media gateway solution, providing essential functionalities for modern communication needs. Its combination of modularity, high-density processing, effective QoS management, and security features makes it a compelling choice for organizations looking to modernize their telecommunications infrastructure while ensuring reliability and performance. As businesses continue to evolve and demand more from their networks, the MGX 8220 offers a pathway to future-ready communications.
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