Communication Network Design in Grid Management
I. Comparison of Communication Technologies
Currently, management across various government departments generally adopts grid-based approaches. Grid communication typically requires two physically isolated networks—a government industry private network and a portal website—and sometimes additional networks such as surveillance networks and video conference networks. Some of these networks have high confidentiality requirements, and physical isolation between networks is mandatory, especially in industries with strict confidentiality requirements such as the military and public security, where VLAN-based isolation between networks is strictly prohibited.
At present, most grid management communication methods rely on public 3G/4G mobile networks or leased broadband networks. Even with additional security measures, the confidentiality level achieved is not high. Some use leased E1 private lines, which can meet confidentiality requirements, but the transmission bandwidth is limited and cannot adequately support extensive video transmission. Additionally, the rental cost of E1 lines is relatively high.
Therefore, grid management communication typically adopts leased dark fiber. Currently, the three major telecom operators and local radio and television networks have laid fiber optic cables to administrative villages in many areas, providing ample resources for fiber leasing in grid management.
Typically, multiple physically isolated network transmissions need to be implemented over a single fiber, along with dispatch telephones, audio monitoring for service quality supervision, and in some cases, wireless trunking forwarding services within the grid.
Three types of equipment can typically accomplish remote communication over dark fiber. Given the large number of remote terminals, expensive equipment such as SDH and OTN is not considered here; only Media Converters, PON, and TDM multiplexing technologies (PDH+PCM) are evaluated. The following is a comparison of these three technologies.
| PON | TDM（PDH+PCM）Optical Transmission |
1. Types of Transmission Services | Only 1 Ethernet | Has 1 Ethernet, telephone, serial port | Can have multiple line-rate Fast Ethernet or line-rate Gigabit Ethernet ports, multiple telephone and serial ports, E1, etc. |
2. Transmission Technology | Packet Switching | Packet Switching and Softswitch | TDM Time-Division Transmission |
3. Isolation Technology | VLAN Virtual Isolation | VLAN Virtual Isolation | Time-division physical isolation provides superior isolation performance |
4. Confidentiality | Low — any media converter can interoperate. If VLAN isolation is used, not only is bandwidth reduced, but all unused packets reach the port, making it vulnerable to decryption. | Medium — with VLAN isolation, not only is bandwidth reduced, but all unused packets reach the port, making it vulnerable to decryption. | High — isolated channels independently occupy dedicated bandwidth, with wire-speed network bandwidth unchanged; only useful packets are transmitted to the user port. |
5. Technical Complexity | Low | High | Medium |
6. Transmission Distance | Long | Short | Long |
7. Telephone Dispatch Technology | Soft dispatch, high latency | Soft dispatch, high latency | Supports dispatch via bothTDM switching and soft switching technologies, with low latency |
8. Number of optical fibers required to achieve physically isolated networks | Multiple cores | Multiple cores | A single fiber core is sufficient |
9. Network Topology Types | Point-to-Point | Tree | Tree |
10. Transmission bandwidth | Bidirectional symmetric | Downstream bandwidth greater than upstream; unsuitable for video surveillance | Bidirectional symmetric; suitable for video transmission |
11. Cost of Implementing Voice Communication | High | Medium | Low |
12. Transmission delay | Large transmission delay without guarantee | Large transmission delay without guarantee | Small and fixed transmission delay |
In PON, since the transmission bandwidth exceeds 1G, the optical module transmission distance (which decreases as bandwidth increases) is relatively short. Combined with the optical splitting introduced by ODN optical splitters, optical attenuation increases and the transmission distance is further reduced. Generally, the uplink bandwidth is relatively small; therefore, PON networks are not suitable for fiber-optic transmission in video surveillance applications.
II. Multi-Channel Transmission System with Uplink/Downlink Transmission Bandwidth
TDM-based optical transmission offers significant advantages when telephone, voice monitoring, and wireless trunking micro-base station forwarding services are required.
PDH and PCM technologies in TDM optical transmission are among the earliest communication technologies and are highly mature. Today, PDH has been enhanced with multiple line-rate Fast Ethernet and Gigabit Ethernet channel transmission capabilities over optical fiber, giving it renewed vitality.
Raytrans' TDM-based optical transmission technology includes central office equipment, aggregation point equipment, and terminal equipment, and shares the same topology structure as PON networks. In environments with video surveillance and long transmission distances, it is the optimal alternative to PON networks.
The Raytrans TDM transmission system includes central office equipment IDM G3CP, aggregation node equipment IDM GP-MPconv, and remote user access equipment IDM NTD421.
On the fiber link from the central office to the aggregation node, the fiber transmission bandwidth is 2.5G, capable of carrying two groups of physically isolated Gigabit line-rate Ethernet channels and dozens of E1 channels.
The fiber transmission bandwidth from the aggregation node to the remote end is 250M, capable of carrying two groups of line-rate Fast Ethernet channels and several E1 channels. E1 channels are typically used for narrowband services such as telephone, voice, and serial data transmission. Currently, it can provide up to 2 telephone lines, one gain-adjustable audio EM2/4-wire interface (for connecting to radio base stations or for audio monitoring), and one RS422/RS485 interface.
The optical fiber transmission bandwidth from the aggregation point to the remote end is relatively low, which is beneficial for increasing the transmission distance.
The central office equipment IDM G3CP is not only a transmission device, but also has rich PCM access functions, as well as powerful information switching and aggregation capabilities:
It can aggregate all broadband Ethernet services;
It can perform non-blocking cross-connection for all remote 64K (or N*64K) services, with a cross-connection capacity of 128E1*128E1;
It can aggregate all remote serial ports via Ethernet interfaces, i.e., functioning as a serial port server;
It can switch remote telephone services, i.e., functioning as a built-in telephone exchange;
It can dispatch remote telephones, voice, and video, satisfying the functions of multimedia dispatch communications, and can also integrate SMS sending and fax sending/receiving functions;
It can provide access to telephone services from higher-level or adjacent units at the same level, with access methods including EM2/4, FXO, No.7 signaling, No.1 signaling, ISDN PRI signaling, etc., including satellite telephones and wireless trunking;
It can connect to dispatch consoles, supporting up to 250 dispatch consoles for joint control. Meanwhile, the dispatch console software integrates GIS geographic information system software, enabling comprehensive dispatch of wired, wireless, voice, data, video, and location information.
III. Functions of the dispatch console at the dispatch center:
The map design is mainly targeted at XX City.
Click "GIS" to open the interface as shown below:
The interface is divided into two parts: the location list on the far left and the XX City map on the right.
The map image can be zoomed in and out within a certain range. The clickable range for annotations needs to be configured to an acceptable area.
First, mark locations on the map (the annotations can be created by the user; currently, the marked locations correspond to those in the list on the left). Then click a location name in Table 1, such as "Tuanhe Street," and the map will display the annotation for that location.
- Clicking an annotation allows you to select operation functions (phone, video, monitoring).
To make a call, first take the handset off-hook, then click the "Phone" button to initiate the call.
If you need to view the video at that location, click the "Video" button and a small video window will pop up, as shown below:
Monitoring is also supported. Speakers and pickups are installed at the location. By adding the speakers and the dispatch console handset to the same conference room, monitoring can be achieved. Conference rooms can be selected (e.g., the left speaker and the right speaker can be in different conference rooms). Click the "Monitor" button to pop up the selection window.
Simply select the target to be monitored.
IV. Configuration of the communications equipment room and command center in grid-based management:
The communications equipment room must meet the physical isolation requirements between the government portal website and the government intranet, and must also provide interfaces for dispatch telephones, public network telephones, SMS, and fax.
Communications equipment room equipment:
No. | Equipment | Qty | Unit Price | Total | Remarks |
1 | Firewall | 1 |
|
| The firewall system is deployed, and all remote users connect to the external network through this firewall.
|
2 | Public Opinion Monitoring Server | 1 |
|
| Internet Behavior Management and Public Opinion Management Software Platform |
3 | Multi-port router | 1 |
|
| Provides broadband access to multiple carriers, reducing the probability of network failures |
4 | Portal server | 1 |
|
| External publicity |
5 | Government cloud processing server | 1 |
|
| Cloud storage, cloud computing |
6 | Intranet Web Server | 1 |
|
| OA System and Grid Software Operating Platform |
7 | Voice Dispatch Communication Server | 1 |
|
|
|
8 | Call Center Server | 1 |
|
|
|
9 | Internal/External Network Security Gateway | 1 |
|
| Used for data switching between the internal and external networks |
10 | Database Software | 1 |
|
|
|
11 | Related software development |
|
|
|
Load balancing devices are not considered for the time being. As business volume grows, two load balancing devices can be deployed at a later stage to provide load balancing for all application systems. At the same time, the two devices can form an HA pair with each other, so that when one load balancing device fails, the other can continue to operate, thereby ensuring normal system operation.
Two WEB servers can also be deployed, both installed with LINUX systems, connected to the load balancing system at the front end. On the one hand, this can reduce the load on the primary server; on the other hand, when one server encounters a problem, the other server can continue to operate.
Disaster recovery backup mirror servers can also be added at a later stage: two servers can be deployed in the telecom or mobile equipment room to perform remote backup of system data and programs, so that they can be started in the event of an unexpected interruption of the primary system, replacing the platform's primary system for emergency operation.
The command center is used for displaying information from user-side video surveillance, audio monitoring, dispatch telephones, the portal website, the intranet, big data processing, etc.
The main configuration of the command center is as follows:
No. | Equipment | Qty | Unit Price | Total |
Remarks |
1 | Audio Mixing Console | 1 |
|
|
|
2 | IPVideo Decoding Matrix | 1 |
|
|
|
3 | VGAvideo switching matrix | 1 |
|
|
|
4 | Large-screen splicing server | 1 |
|
|
|
5 | Video Wall | N*M |
|
|
|
6 | Speaker | 2 |
|
|
|
7 | Microphone | N |
|
|
|
8 | Printer | 1 |
|
|
|
9 | SMS Gateway | 1 |
|
|
|
10 | Custom control console with telephone | N |
|
|
|
11 | Console computer | N units |
|
|
|
12 | Intelligent Lighting Control System | 1 |
|
|
|
13 | Fresh Air System Controller |
|
|
|
|
No. | Equipment | Qty | Unit Price | Total |
Remarks |
1 | Multimedia dispatch software | 1 |
|
|
|
2 | Call Center Software | 1 |
|
|
|
Central Office Equipment:
Shall provide SDH interfaces STM-1 and STM-4, enabling connection to the carrier's SDH optical fiber communication network for interconnection with higher-level authorities or other business units within the city;
Shall provide 200M bandwidth (2 wire-speed 100M) fiber optic interfaces to each node, along with telephone and voice services. To minimize fiber count, the fiber to township/street offices shall be capable of transmitting 2000M (2 wire-speed 1000M Ethernet) and more than 10 E1 channels. After reaching the township, low-speed fiber interfaces (with a maximum single-fiber transmission distance of 80KM for extended reach) shall be used to connect to administrative villages.
The central office equipment shall integrate dispatching functions to enable scheduling of communication resources within remote grids, namely:
Basic Functions: Call, call transfer, call forwarding, call park, answer, call pickup, hold/resume, do-not-disturb setting, and other operations.
Dispatch Functions: Forced insertion, forced release, call takeover, monitoring, call barring, manual/automatic transfer, group paging, group call, conferencing, dynamic grouping, hierarchical collaborative dispatch, and other operations.
Broadcast Functions: Broadcast, loudspeaker announcement, environmental monitoring, and other functions. Broadcast includes instant broadcast and scheduled broadcast; broadcast audio sources can be selected from internal audio files, external audio sources, or TTS files for playback.
Trunking Intercom: Capable of dispatching intercom radios of different frequency bands, different models, and different standards (digital/analog); talk rights can be controlled through the dispatch software interface.
Conference Functions: Conference convening, conference scheduling, conference member identity authentication, multiple simultaneous conferences, conference process monitoring, and other operations.
The provided dispatch software must be capable of integrating with GIS geographic information systems and synchronized surveillance video recording;
The central office equipment must provide an interface for the call center software platform.
Aggregation Node Equipment:
Large upstream optical fiber transmission capacity, capable of transmitting 2 wire-speed 1000M Ethernet channels and 10 E1 bandwidths, providing 2 mutually redundant uplink interfaces;
Downstream capability to split into no more than 10 low-speed optical fiber interfaces (ensuring each optical port receives 2 wire-speed 100M bandwidth), facilitating longer transmission distances over single-core fiber, up to 80KM;
All optical interfaces adopt SFP interfaces for easy replacement based on distance and other environmental conditions;
Management functions for each remote device.
Township/Street Communication Access Equipment:
Supports dual-fiber mutual redundancy; optical fiber transmission bandwidth of 2.5G;
Up to 24 groups of E1, or provides 30 telephone lines or audio monitoring, trunking micro base station access, and other services;
2 physically isolated wire-speed 1000M Ethernet channels, totaling 2000M;
4 physically isolated wire-speed 100M Ethernet channels, totaling 400M;
Provides standard SNMP network management interface.
User Access Terminal Equipment:
Provides 2 mutually redundant SFP optical fiber interfaces;
Provides two groups of physically isolated Ethernet channels with a total bandwidth of 200M. 4 interfaces, where interfaces 1, 2, and 3 share 1 wire-speed 100M Ethernet channel, which can be isolated via VLAN partitioning; the 4th Ethernet group is a physically isolated dedicated 100M bandwidth Ethernet channel.
Capable of providing 2 telephone lines, one audio EM2/4-wire interface with adjustable gain (for connecting radio base stations or for audio monitoring), and one RS422/RS485 interface.
V. Communication Transmission Equipment
Leased dark fiber.
User-Side Equipment
| 设备名称/行政区 | 数量 | 单价 | 合计 | 备注 |
Municipal Information Center — Central Office Equipment | IDM G3CPMain Chassis | 2 | | # | Each chassis can accommodate up to 8 2.5G access cards |
Power Supply Unit | 4 | | # | Dual power supply with mutual backup |
ODXCcard | 4 | | # | Cross-connects various services across the entire chassis |
NMS Card | 2 | | # | Connected to the NMS computer |
2.5G-USERCardA | 7 | | # | Connected to IDM GP-MPconv, up to 4 units can be connected, 2 units recommended |
2.5G-USERCardB | 7 | | # | Connected to the IDM OMP3500, supports connection of 1 unit |
WGDispatch Panel | 1 | | # | Provides dispatch for remote telephones and access for external line calls; can connect to the dispatch server and dispatch console |
16E1DXC Card | 1 | | # | Provides aggregation of telephony services from multiple user optical ports |
IP Softswitch Gateway Card | 1 | | # | Provides conversion from external or internal telephone lines to IP softphone |
Voice Card FXO | 2 | | # | Provides 30 trunk line telephone interfaces |
42*E1Card | 2 | | # | Used for interconnecting devices, or providing backup E1 channels |
Equipment Cabinet | 1 |
|
|
|
| Distribution Cabinet | 1 |
|
| Cabinet and Distribution System |
Township/Street | IDM OMP3500 | 7 | | # | High-bandwidth access device for township/street offices, providing 6 groups of physically isolated Ethernet ports with a total bandwidth of 2400M |
Township/Street | IDM GP-MPCONV | 14 | | # | Intermediate node fiber access device with bandwidth adjustment and allocation functions |
Township/Street Office | Equipment and Distribution Cabinet |
|
|
|
|
Grassroots Grid Access | IDM NTD421 | 80 | | # | Grassroots access device, providing 2 groups of physically isolated Ethernet, telephone and audio access, with a total bandwidth of 250M |
| | | | # | |
- User Equipment
No. | Equipment | Qty | Unit Price | Remarks |
1 | Portal computer | 1 |
| External publicity and reporting |
2 | Intranet computers | 1 |
| Information collection and query |
3 | Network camera | 1 |
| Service quality monitoring and security surveillance |
4 | Monitoring microphone | 1 |
| Ambient sound detection, service quality monitoring |
5 | Loudspeaker | 1 |
| Public address broadcasting, remote command, video conferencing |
6 | Telephone set | 1 |
| Used for business communication and dispatch communication; the government no longer needs to subsidize telephone charges |
7 | Trunked radio forwarding walkie-talkie | 1 |
| Standard walkie-talkies connected to the communication equipment can achieve trunked micro-power forwarding (optional) |