Routing Performance?

Does routing performance control by Hardware or Routing algorithm ?. Who takes most most factor to decide the performance.

[whcdavid]

I am not an expert on this, but nowdays control by algorithm. Normally most of the companies always upgrade the software to get more performance. They don't upgrade the hardware which is very expensive. Is any other expert there?.

Thank You
David.K

This is a complex question that depends on vendor implementation and traffic patterns. Most "high end" routers bear all traffic in hardware, with software used only for maintaining the route table utilized by the hardware; speaking routing protocols to neighboring routers; and administrative functions (SNMP polling, configuration).

Some mid-range routers still forward using hardware that organizes traffic into "flows." When an IP packet from a source / destination pair that is not known by the hardware is received, the packet's header (or in some old implementations, the whole packet) is copied to the memory accessible by the main CPU and software. That software looks up the packet's destination, then creates a new flow entry in the router's hardware, and either directs the hardware to forward the packet to its destination, or copies the packet back to the hardware. These products can be adversely affected by DDoS attacks intended to cause new flows to appear more rapidly than the software can process them.

Other routers, and all PC routers in particular, do all their packet forwarding using traditional software on their main CPU. The performance of these platforms is typically much more limited than hardware based routers like those described above.

Juniper has a new product series, the J-series, which does all packet forwarding in software. It is designed for <= 90Mb/s branch office or customer CPE applications, and is substantially less expensive than their M-series core routing products, which do all fowarding in hardware with no flows or other software assistance. The advantage of the J-series, besides price, is that it offers many advanced features (NAT, stateful firewall, tunnel service) in software which require expensive hardware cards on the M-series. With this example you can see the advantages (features and cost) of software based routers as well as hardware based routers (predictable, high performance).