Application viewpoint: understanding the concept of packet forwarding rate in vrouters

Packet forwarding rate is an important indicator that affects route performance. Here we mainly explain the specific application of packet forwarding rate in routing. There are many indicators when describing the performance of a vswitch, such as switching capacity (Gbps), Board bandwidth (Gbps), throughput or packet forwarding rate (Mpps) and so on.

The most important performance indicator of a vswitch is the throughput (Mpps), because it can ultimately reflect the performance indicator of the vswitch application. Users generally go straight to this topic, it depends on the number of packages that the product can forward per second. Throughput generally refers to the unit port theoretical throughput when the packet length is 64 bytes is the product of the number of fully configured ports of the switch, that is, the throughput (Mpps) = number of fully configured ports X theoretical port throughput Mpps ). The switching forwarding performance is measured in the unit of "Mpps" Million Packet Per Second)-"millions of packets Per Second", that is, the number of packets that the switch can process Per Second. The higher the number, the higher the exchange performance of the switch. The term "throughput" is the most advanced in the Performance description of the switch, but it is also mentioned in the routing path.

Vro has performance indicators similar to those of vswitches. Vro performance has two important indicators: backplane capacity, backplane bandwidth, and bus bandwidth, which refer to the backplane capacity or bus capacity of the vro. Throughput refers to the router's packet forwarding capability. Generally, kpps is used as the unit for the router's throughput, that is, "thousands of packets per second", because the average router's LAN-to-WAN packet forwarding rate is not very high, compared with a vswitch, it can easily reach the number of million packets per second, which is much smaller, so "Mpps" is not used ". Unless it is a high-end Backbone Router such as Cisco in the Cisco 10000 vro, it's packet forwarding rate of 6.2 Mpps. Another reason is that in the high-end field, the boundaries between routers and switches are actually vague. Some products are simply called "Exchange routers", and the forwarding capability is very high.

Routers can be divided into high-end routers and low-end routers. A vro with the packet switching capability> IMpps can be called a high-end router, and a vro with the packet switching capability below IMpps can be called a low-end router. For example, the packet forwarding capabilities of Cisco 12000 series and 3600 series routers are millions of packets per second, while the 2600 series and series are low-end routers. Therefore, the router generally uses kpps as the unit.

When evaluating the packet forwarding rate of A vro, some evaluation tools will use the following six bytes of data packets for the evaluation standard: 64B, 128B, 256B, 512B, 1024B, B bytes of data packets, and the most common is the 64 B packet and B packet respectively. Cool found this line of "E" on Cisco's website: "throughput of the Cisco 2651XM at the smaller packet size of 64 bytes ", therefore, cool believes that Cisco will use 64 bytes of small packets as the evaluation standard for its own products with the large stream. Is this too far-fetched? Cool felt a little sincere and sincere in his heart, but when I thought about it, everyone would use small packets as the standard. Doesn't it seem that their products are more competitive? There is no need to use a large package or a larger package.

However, if there is no special explanation of the router's throughput, its business data packet should be the most common service, or the most common lan to wan forwarding capability. However, for a VPN-like business, it is definitely a "big package". For example, a 168-bit 3DES package is a 1400-byte package ), because the VPN service transmits confidential data on the public network, it is necessary to add a lot of encrypted "bytes" to the VPN data packets. Such a package is very large and correspondingly, the router processing is slow, and the forwarding capability is reduced accordingly.

Conclusion: The above is only cool's reflection on the issue raised by netizens on the forum. We also hope that readers will participate in the discussion, more importantly, when purchasing a router, You can correctly examine the forwarding capability indicators of the product, so that the purchased product can be competent for your network business needs.