Chapter

Frame Relay Service Modules (FRSMs)

•The very high-speed FRSM (MGX-FRSM-HS2) supports all the features of the standard FRSM (service interworking, FR/ATM network, FUNI, and so on).

•As with the other high-speed frame service modules, 1:1 hot-standby redundancy is supported using Y-cabling on the back cards.

Frame Relay Access Service Module

The Frame Relay Access Service Module (FRASM) is a two-card set consisting of a FRASM front card (supporting channelized,T1, 8 port), and an 8T1 back card. Up to ten FRASM modules may be installed in a shelf in slots 5 through 14.

The main function of the FRASM is to allow IBM network devices and mainframes (IBM 3270 terminals communicating with an IBM mainframe) operating under SNA/SDLC or 3270/BSC (binary synchronous) protocols to communicate with each other using Frame Relay over an ATM network. This is an alternative to the conventional method of using T1, E1, V.35, or X.21 leased lines.

FRASM modules support the following logical connections and protocols:

•PU4 (Physical Unit 4) to PU2 over 3270/Bisync link

•PU4 to PU2 over a SNA/SDLC link

•PU2 to PU2 over a SNA/SDLC link

•PU4 to PU4 over a SNA/SDLC link

FRASM modules support the following end-to-end connections on a connection-by-connection basis:

•SNA/SDLC to SNA/SDLC (STUN for Serial TUNnel)

•SNA/SDLC to Frame Relay (BNN for Boundary Network Node)

•3270/Bisync to 3270/Bisync (BSTUN for Block Serial TUNnel)

STUN Connections

STUN, short for Serial TUNnel, is an IBM technique for transmitting SNA (SDLC) traffic over Frame Relay networks by encapsulating the SNA frames within Frame Relay frames using the protocol of RFC 1490.

There are two methods of achieving this

1.passthrough (or transparent)

The passthrough method encapsulates the entire SNA 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 SNA network.

2.local acknowledgment

The local acknowledgment method terminates the SNA traffic at the Frame Relay network interface and encapsulates data only, the SNA frames are then reconstructed at the other end.

Both passthrough and local acknowledgment methods are supported by the FRAM.

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

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

 

 

Cisco MGX 8220 Installation and Configuration

 

 

 

 

 

 

 

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

 

 

4-11

 

 

 

 

 

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Cisco Systems MGX 8220 manual Frame Relay Access Service Module, Stun Connections
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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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