Summary of network device hard core technology insider router (Part 2)

Let's go back to Eight questions at the beginning ：

1. Why do routers generally not use switches ASIC Realization ？
2. Realization 10G Ethernet and 10G PoS Interface line speed forwarding , Which requires high router ？
3. Why multicore CPU Implemented router , When opening a variety of businesses , There will be a drop in performance ？
4. Multi core implementation of routers and NP Compared with the implemented router , Which is more suitable for increasing NAT function ？
5. PPPoE and IPoE Which can be in ASIC Upper processing ？ Why? ？
6. Why is the general router FIB The watch is always better than RIB Small gauge ？
7. Routers can be like switches , Reduce forwarding delay through direct forwarding mode ？
8. In recent years , Home routers are free , Why did the business model of inserting advertisements into web pages fail ？

Now? , Every question has an answer .

Q1. Why do routers generally not use switches ASIC Realization ？

A1. Because the switch ASIC The ability of is relatively simple , For the backbone network of operators FIB Table item , Requirements for large cache , The edge of the metropolitan area ends PPPoE, hierarchical QoS The requirements of , Requirements for enterprises to export multiple businesses , Can not fully meet . therefore , In a general way , Routers in these scenarios use NP And multi-core processors .

Q2. Realization 10G Ethernet and 10G PoS Interface line speed forwarding , Which requires high router ？

A2. 10G PoS Demand is high , Because it needs real-time processing HDLC Package codec .

Q3. Why multicore CPU Implemented router , When opening a variety of businesses , There will be a drop in performance ？

A3. Because multi-core CPU Handle multiple businesses , Such as tunnel stripping 、DPI etc. , It will consume more CPU Instruction cycle .

Q4. Multi core implementation of routers and NP Compared with the implemented router , Which is more suitable for increasing NAT function ？

A4. Multicore . Multi core programmability is stronger , Specially , Realization IPv6 To IPv6 Of NAT It has a big advantage .

Q5. PPPoE and IPoE Which can be in ASIC Upper processing ？ Why? ？

A5. IPoE Can be in ASIC Upper processing , Because the forwarding plane only needs to end QinQ And multicast replication . This is a ASIC Strengths of .

Q6. Why is the general router FIB The watch is always better than RIB Small gauge ？

A6. RIB stay DRAM In the maintenance ,FIB Table in TCAM In the maintenance , The cost of the former is much lower than that of the latter .

Q7. Routers can be like switches , Reduce forwarding delay through direct forwarding mode ？

A7. Can not be , This will result in failure to properly process fragmented messages .

Q8. In recent years , Home routers are free , Why did the business model of inserting advertisements into web pages fail ？

A8. because HTTPS The popularity of .

Do you all understand ？