KR20000046355A - Network interface apparatus of remote access system - Google Patents

Abstract

PURPOSE: A network interface apparatus of the remote access system is provided to interface the frame relay network and the ISDN network by an identical hardware in the remote access system to connect a network and a network. CONSTITUTION: A line interface and framer unit(221) interfaces networks by an E1 link. A PLL(222), synchronized with a clock received from the line interface and framer unit(221), provides a system clock. A time switch(223) separates a D channel from an E1 frame, outputs it to a main processor(225) and divides the data channels of 30 channels in case of interfacing with an ISDN network. In case of interfacing with a frame relay network, the time switch(223) provides 31 channels without separating the D channel. An HDLC processing unit(224) processes the 30 channels from the time switch into a channelized HDLC protocol in case of interfacing with the ISDN network and, in case of interfacing with the frame relay network, processes the 31 channels into an unchannelized HDLC protocol. The main processor(225) carries out a required signaling procedure, receiving the D channel data from the time switch(223).

Description

NETWORK INTERFACE BOARD OF REMOTE ACCESS SYSTEM

The present invention relates to a network interface device capable of matching a frame relay network and an ISDN network with the same hardware in a remote access system (RAS) for connecting a network.

In the current communication network, since various types of individual networks are independently implemented, it is necessary to connect the network with the network until a new network is integrated. The Remote Access System (RAS) is a device for satisfying such a need, and connects networks by converting protocols of various networks.

One example of a conventional remote access system (RAS) for connecting a network as shown in FIG. 1 is a public telephone network (PSTN) 102, an ISDN network 104, and a frame relay network (Frame Relay: 106). To match. Referring to FIG. 1, a public telephone network 102 is a communication network for delivering voice signals to other subscribers in a network by performing circuit switching according to call requests of telephone subscribers, and ISDN network 104 is an ISDN subscriber. It is a comprehensive information communication network capable of providing 2B + D access to the network, and the frame relay network 106 is a communication network for transferring digital data between computers through packet exchange. In particular, the frame relay is a new protocol that significantly reduces the errors generated in the network according to the development of semiconductor and communication technology, and improves the X.25 protocol by requiring high-speed transmission in accordance with the broadband of service areas such as multimedia. It is made under the premise that the error occurrence rate is very small, so that the error recovery capability is lower than that of the X.25 protocol, but the transmission rate is much faster than the X.25 protocol.

In FIG. 1, the remote access system 100 includes a PSTN interface board 110 for matching with the PSTN network 102 and an ISDN interface board 120 for matching with the ISDN network 104, a protocol processing unit 130, and a frame relay. Frame relay interface board 140 for matching with the network 106, and a channel service unit (CSU) 150 for arbitrating V.35 and E1.

The remote access system 100 is connected to the public telephone network 102 in the form of an E1 trunk to provide a channel dependent signaling (CAS), and is connected to the ISDN network 104 in the form of an E1 trunk to form a common line signaling (CCS). ) Is connected to the frame relay network 140 in the form of an E1 link according to the frame relay protocol.

However, the current frame relay network has a stable transmission line and a reduced bit error rate of data, thereby serving the same E1 (2.048Mbps Unchannelized HDLC) transmission rate as the PSTN network. The ISDN network also uses the same E1 line interface (2.048Mbps Channelized HDLC) as the PSTN network. However, since the frame relay network is based on the protocol of the public data network (PSDN) (that is, X.25), it must be equipped with a channel service unit (CSU) for the V.35 interface, thereby increasing the cost.

Accordingly, an object of the present invention is to provide a network matching device that does not require a channel service unit (CSU) to interface with a frame relay network and can be commonly used for an ISDN network interface and a frame relay network interface.

In order to achieve the above object, the apparatus of the present invention, in the remote access system that can be connected to the protocol processing unit by matching the ISDN network and the frame relay network to a common interface board,

The common interface board, line interface and framer unit for matching the network to the E1 link; A phase locked loop for providing a system clock in synchronization with a clock received from the line interface and the framer unit; In case of interfacing with ISDN network, it separates D channel from E1 frame and outputs it to main processor, and separates 30 channel data channel, and when interfacing with frame relay network, provides 31 channels without separating D channel. Time switch; When interfacing with an ISDN network, it receives 30 channels from the time switch and processes them with a channelized HDLC protocol.When matching with a frame relay network, it receives 31 channels from the switch and processes them with an unchannelized HDLC protocol. An HDLC processor for outputting to a protocol processor; And a main processor receiving the D channel data from the time switch and processing a predetermined signaling procedure.

1 is a block diagram showing the configuration of a conventional remote access system;

2 is a block diagram showing the configuration of a remote access system according to the present invention;

3 is a detailed block diagram when connecting an ISDN network to a remote access system according to the present invention;

4 is a detailed block diagram when connecting a frame relay network to a remote access system according to the present invention;

FIG. 5 is an example of implementation of the network matching device shown in FIG. 2.

* Explanation of symbols for main parts of the drawings

200: remote access system 202: public telephone network (PSTN)

204 ISDN 206 frame relay network

210: PSTN interface board 220: first common interface board

230: protocol processor 240: second common interface board

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a block diagram showing the configuration of a remote access system according to the present invention, Figure 3 is a detailed block diagram when connecting the ISDN network to the remote access system according to the present invention, Figure 4 is a frame relay in accordance with the present invention Detailed block diagram when connecting a network to a remote access system.

In the remote access system to which the present invention is applied, as shown in FIG. 2, the PSTN interface board 210 for matching with the PSTN network 202 and the first common interface board 220 for matching with the ISDN network 204. , A second common interface board 240 for matching with the protocol processor 230 and the frame relay network 206.

The remote access system 200 is connected to the public telephone network 202 in the form of an E1 trunk to provide a channel dependent signaling (CAS), and is connected to the ISDN network 204 in the form of an E1 trunk to form a common line signaling (CCS). The frame relay network 206 is connected to the frame relay network 206 according to the frame relay protocol in the form of an E1 link.

And the detailed block of the "A" part that combines the remote access system (RAS) with the ISDN network 204, as shown in Figure 3, the first common interface board 220, protocol processing unit 230, the second common The first common interface board 220 includes a line interface and a framer unit 221, a PLL 222, a time switch 223, an HDLC processor 224, and a main processor 225. It is composed.

In addition, the detailed block of the "B" part (in FIG. 2) for matching the remote access system (RAS) with the frame relay network is shown in Figure 4, the first common interface board 220, the protocol processing unit 230, The second common interface board 240 includes a second interface board 240, a line interface and framer unit 241, a PLL 242, a time switch 243, an HDLC processor 244, and a main processor (244). 245).

Comparing FIG. 3 and FIG. 4, it can be seen that the configurations of the first common interface board 220 and the second common interface board 240 are the same. Therefore, according to the present invention, the ISDN network and the frame relay network are identical. Can match each one.

Referring to FIG. 3, in the HDB3 matched bit stream coming from the ISDN network 204, bit synchronization and frame synchronization (LIU) are performed at the line interface and framer unit 221, and E1 link signaling matching (Framer) is performed. The clock extracted from the line interface unit is provided to the PLL 222, and the PLL 222 phase-locks the received clock to generate a local system clock.

In the case of matching with the ISDN network, the time switch 223 separates the D channel and sends it to the main processor 225 to process the D channel protocol. Of the 32 channel data extracted from the time switch 223, 30 channels except for the frame channel and the signaling channels "0" and "16" channel are transferred to the HDLC processor 224, and the HDLC processor 224 is the actual data. The B channel 30 channels, which are channels, are processed according to the channelized HDLC protocol and then output to the protocol processor 230.

Referring to FIG. 4, in the HDB3 matched bit stream coming from the frame relay network 206, bit synchronization and frame synchronization (LIU) are performed at the line interface and framer unit 241, and E1 link signaling matching (Framer) is performed. . The clock extracted from the line interface unit is received by the PLL 242, and the PLL 242 phase-locks the received clock to generate a local system clock.

In the case of frame relay network matching, the time switch 243 does not separate the D channel, and sends all 31 channels except the frame channel (channel 0) to the HDLC processor 244. The HDLC processor 244 processes the B channel 30 channels, which are actual data channels, according to the unchannelized HDLC protocol, and then outputs them to the main processor 245.

The protocol processor 230 transmits the ISDN subscriber data to the frame relay network according to the frame relay protocol, and transmits the information received from the frame relay network to the ISDN subscriber.

FIG. 5 is an example of an implementation of the network matching device shown in FIG. 2. ), The framer 509, the line interface 510, the PLL 511, and the like. The 68360 501 is connected to the 68360 of the protocol processor 230 through the SCC1 bus, the 68360 501 is connected to the time switch 508 through the SCC4 for LAPD transmission, and the PLL 511 is phase-synchronized 4 MHz. It provides system clocks such as 2MHz and 8KHz. Channel information and data are stored in the DPRAM 504, and the 68MH360 505 processes the HDLC protocol of the channel or unchannel type.

As described above, according to the present invention, since two networks can be matched to one board, the manufacturing cost of the entire system can be reduced, and in particular, the cost can be reduced by eliminating the channel service unit (CSU). In addition, there is an effect that the installation is convenient.

Claims (1)

In the remote access system that matches the ISDN network and the frame relay network to the common interface board to be connected to the protocol processing unit, The common interface board, A line interface and framer unit for matching the network to the E1 link; A phase locked loop for providing a system clock in synchronization with a clock received from the line interface and the framer unit; In case of interfacing with ISDN network, it separates D channel from E1 frame and outputs it to main processor, and separates 30 channel data channel, and provides 31 channel without separating D channel when interfacing with frame relay network. Time switch; In case of interfacing with ISDN network, it receives 30 channels from the time switch and processes them with channelized HDLC protocol, and when matching with frame relay network, receives 31 channels from the time switch and unchannelizes ( unchannelized) HDLC protocol for processing the HDLC protocol output to the protocol processor; And And a main processor receiving the D channel data from the time switch and processing a predetermined signaling procedure.