Summary of high-performance S3400 aggregation layer Switches

There are many things worth learning about the aggregation layer switch. Here we mainly introduce the summary of the high-performance S3400 aggregation layer switch. By using the BDCOMS3400 series as the aggregation layer switch, the network transformation of Yangzhou radio and television is remarkable.

As the first carrier in China to use optical cables, Yangzhou Radio and Television, which occupies more than 70% of Yangzhou's network share, initially adopted a typical three-tier network. With the increasing number of radio and television users in the past two years, the networks of Yangzhou radio and television are increasingly unable to meet the needs of the current situation: load increases, the original aggregation switch cannot enable Layer-3 devices, and broadcast packets occupy about half of the traffic on the backbone line, A large amount of bandwidth is wasted. The increase in the number of users also brings about a lot of security problems. ARP attacks, IP address tampering by user tokens, and FLOOD attacks FLOOD the network, as a result, radio and television technicians have spent a lot of time on these security maintenance.

In view of this situation, Shanghai Boda believes that the current network bottleneck of radio and television is the convergence layer equipment. The aging of the Convergence layer equipment leads to the bottleneck of the current radio/TV network. The convergence layer switch can achieve the following functions: the convergence layer must be a three-layer device, in this way, DHCP server functions can be deprecated to the aggregation layer to reduce the burden on core Switches of network services; the core vswitch CISCO4500 of the Video Service identifies the request packet of the set-top box and forwards the packet to the aggregation layer. For security, try to prevent ARP attacks from flooding users in several communities under the aggregation layer, therefore, the aggregation layer must have sufficient three-layer processing capabilities and be extremely stable.

In terms of network topology, although only the network devices at the aggregation layer are replaced, Boda has enabled a large number of functions on the switches at the aggregation layer: residential users no longer obtain addresses through CISCO6500, the responsibility for allocating Internet addresses is placed on the BDCOMS3400. For the particularity of the set-top box request package, Boda performs special processing on the BDCOMS3400. The function of identifying and forwarding the set-top box data packets is implemented by the aggregation layer, ensure the CPU of CISCO4500;

Although both the set-top box and PC automatically obtain the address, the request packets sent by the set-top box and PC are completely different. The common network cannot identify the request packets sent by the set-top box, therefore, when many manufacturers test the radio/TV aggregation layer switch, in the video service network, the aggregation switch only provides the Layer 2 function, so the burden is still on the core CSICO4500, for video service networks, other manufacturers' solutions have not been improved.

Boda has carried out a lot of secondary development work on the actual situation of Yangzhou Radio and Television. A large number of functions have been enabled on the S3400 switch of the aggregation layer. The distributed processing of multiple S3400 instances shares the pressure on the core network equipment, and reduced the scope and risks of network faults, greatly improving the overall network operation.

The main features of the Boda solution include automatic identification of set-top box address requests and forwarding to upper-layer devices for processing; DHCP distributed processing of PC addresses to reduce pressure on core devices; automatically filters ARP spoofing, DHCP spoofing, ARP attacks, and virus attack packets, prevents unauthorized IP address tampering, and protects ports from environmental protection to prevent loop and broadcast storms.

From the initial test in January to the present, Yangzhou Radio and Television has adopted BDCOMS3400 as the aggregation layer switch in large batches, And the CPU Of the two core Switches of Radio and Television has dropped to 40%. Due to the layer-3 connection between aggregation and core, the number of broadcast packets on the backbone line has been reduced to less than 5%. At the same time, the residential users cannot access the Internet due to network attacks and spoofing. According to the current situation, at the peak of Internet access, more than 2000 home pcs under one aggregation switch are surfing the internet, and nearly 1500 set-top boxes are on-demand video, both gigabit optical cables maintain a traffic of more than 700 Mb/s, but the CPU of the aggregation switch is only about 20%, which eventually won the praise of Yangzhou radio/TV users.

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In response to the aging of Yangzhou radio/TV aggregation layer equipment, Boda has carried out a lot of secondary development work, enabling a large number of functions on the aggregation layer switch S3400, multiple S3400 distributed processing reduces the pressure on core network devices and reduces the scope and risks of network faults.