[Understand the bearer in seconds] Hot technical term - "satellite router"

Today, let’s learn technical terms with Document Master: Satellite Router - enhance business expansion capabilities and improve operation and maintenance efficiency.

Q.What is a satellite router?

A. Satellite router is a solution that virtualizes several physical routers into one logical router. It is generally composed of a convergence router and multiple access routers, where:

• Aggregation router: It is defined as the central node and acts as a control node. It is responsible for establishing forwarding channels, issuing services and controlling traffic. It can manage connected satellite nodes.
• Access router: defined as a satellite node, as an access node, equivalent to the board of the central node, automatically discovered and managed by the central node.

After enabling the satellite router solution, a virtual router with super scalability is built between different routers through automatic discovery, automatic configuration, and automatic forwarding mechanisms. The user interface only displays a single management network element, which can significantly reduce operation and maintenance costs.

For example, the system is like an express delivery company. The head office distribution center will dispatch the express to various outlets. The outlets are responsible for sending and receiving the express. The system can flexibly increase or decrease outlets as needed. Users only need to deal with one "express delivery brand" and do not need to understand how the collaboration behind the scenes works, thereby improving efficiency.

Q.Why do I need a satellite router?

A. In existing network applications, aggregation routers face a large number of low-speed service access requirements. The conventional line card direct-out solution of configuring a large number of GE line cards has many problems.

Take the common 8-slot aggregation router as an example:

• Limited GE ports: The 8 slots support a limited number of GE boards, resulting in poor service scalability. Upgrading to 18-slot equipment requires increased cost, space, and power investment.
• Device bandwidth waste: The high proportion of low-speed GE ports results in low slot bandwidth utilization.

To solve the above problems, we tried to connect a small access router to expand the GE port, and at the same time, the aggregation router was connected to the access router by configuring a small number of 10GE boards.

Although this solution can meet expansion needs and reduce costs, the complexity of operation and maintenance is significantly increased. For example, the surge in the number of network elements has doubled the workload of configuration and commissioning, and the maintenance of a large number of network elements on the interface has reduced operation and maintenance efficiency.

To address the O&M challenges of the downstream access router solution, the industry has introduced a satellite router solution that virtualizes the aggregation router and the downstream access router into a single network element, which has the following advantages:

• Strong scalability: By controlling the number of satellite nodes, unlimited expansion of low-speed business interfaces can be achieved.
• Efficient operation and maintenance: Automatic discovery, automatic configuration, and automatic forwarding between router entities, and the management interface only requires the maintenance of a single device.
• Cost reduction: Greatly reduce the number of aggregation router boards and avoid equipment stacking or upgrading.
• Space saving: There is no need to configure a large number of low-speed line cards, and small aggregation routers can be used to reduce the space requirements of the equipment room.
• Power consumption optimization: The access router and small aggregation router are combined to achieve green energy saving.

Q.How does a satellite router work?

A. The satellite router solution introduces a large number of innovative technologies in the control plane, data plane, and management plane, which jointly realize automatic discovery, automatic configuration, automatic message conversion, and simplified network management interface of satellite nodes, greatly improving the efficiency of network operation and maintenance.

• Control plane: When a satellite node goes online, it interacts with the central node through the LLDP (Link Layer Discovery Protocol) extended protocol to achieve automatic discovery; the central node generates a satellite node logical interface based on the reserved slot number and reports it to the network management, and then sends the configuration through the Netconf protocol, and the satellite node automatically completes the configuration.
• Data plane: When forwarding data, the interconnection interface between the central node and the satellite node adds the ECID (E-channel Identifier, data channel number value) VLAN Tag in the message to achieve automatic mapping and forwarding between the virtual satellite interface and the physical port of the satellite node.
• Management plane: The network management interface only displays the central node, and the satellite nodes are presented as their remote boards. The status information is uniformly reported by the central node through the Netconf protocol.

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Q. Satellite router vs regular router

A.

• Satellite router: A virtualization solution for several ordinary routers that supports more low-speed interface access and reduces the number of network management elements.
• Ordinary routers: can only stack devices or line cards, requiring higher equipment investment and operation and maintenance costs.

Q. Satellite router application scenarios and industry application progress

A. Satellite routers are suitable for scenarios where a large number of low-speed interfaces are expanded on the aggregation core router.

At present, the satellite router solutions of mainstream communication equipment vendors all have mature commercial capabilities. Among them, ZTE's satellite router solutions have been deployed on a large scale in existing networks such as Malaysia TM and Turkey TT and have been operating stably for a long time, greatly improving customers' network deployment and operation and maintenance efficiency.