Lucent Technologies PacketStar PSAX 4500, Руководство пользователя

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Chapter 3 System Features
User Interfaces
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PacketStar
®
PSAX 4500 Multiservice Media Gateway User Guide , Issue 2 Release 8.0.0
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The IMA identifier (ID) is an 8-bit (0-255) identifier for this IMA group.
There is no significance to any particular values of IMA IDs. Since the
IMA ID is used to identify a group to the far-end, pick a unique value
instead of leaving it as the default of
0 .
Frame Relay-to-ATM Interworking
Frame relay-to-ATM interworking is performed at the network level, Frame
Relay Implementation Agreement FRF.5, and at the service level, FRF.8. This
allows a
PacketStar Multiservice Media Gateway to adapt and concentrate
traffic from one frame relay network and transmit it to other frame relay or
ATM networks. In this way, the Multiservice Media Gateway acts as a gate-
way between routers, remote-dial access servers, systems network architec-
ture (SNA) equipment, and other devices configured for frame relay opera-
tion.
FRF.5 Encapsulating
Frames
With FRF.5 network level interworking, frames are encapsulated within ATM
cells at the network ingress point and "tunneled" through the ATM network.
At the network egress point, the ATM cell headers are removed and the
frames are reassembled for delivery to a frame relay device.
FRF.8 Converting
Frames
With FRF.8 service level interworking, frames are converted into one or more
ATM cells at the network ingress point. At the network egress point, the ATM
cells are delivered to an ATM device. This conversion is compliant with both
the FRF.8 implementation agreement and the IEFT multiprotocol encapsula-
tion specifications (RFC 1490, RFC 1483). FRF.8 interworking is performed at
the end of the ATM network that connects to the frame relay device.
Note:
FRF.5 and FRF.8 are not interoperable and cannot be used at both
sides of a network. You may wish to use an FRF.8 approach for
applications involving interconnectivity between two frame relay
devices because the capabilities of FRF.8 include those that are
available with FRF.5.
Frame Relay-to-Frame Relay Interworking
In addition to frame relay-to-ATM interworking, it is possible to configure a
Multiservice Media Gateway for strictly frame relay operation. A frame relay-
to-frame relay connection can be made between two ports of a Multiservice
Media Gateway if both ports have frame relay capacity. In this case, frame
relay data received by one of the ports is converted to ATM cells for transmis-
sion across the backplane of the Multiservice Media Gateway, and then con-
verted back into frame relay for transmission from another port.
GR-303 Interface
The Telcordia Technologies General Requirements 303 standard provides for
both an open interface network architecture and a digital loop carrier system
that operates on T1 circuits. This standard allows a remote terminal such as a
central office
PacketStar PSAX Multiservice Media Gateway to flawlessly