CODEWITHSUNDEEP
network-programmingvirtualrouterhost
user5104026
user5104026

Reputation: 698

Software Routing

"Commercial software routers from companies such as Vyatta can typically only attain transfer data at speeds of up to three gigabits per second. That isn’t fast enough to take advantage of the full speed of a typical network card, which operates at 10 gigabits per second." [1]

How is the speed of the network interface card relevant in this scenario? Aren't software routers connecting multiple Virtual Machines running on the same physical host? [2] Unless a PC has multiple network interface cards, it is unlikely that it functions as a packet switch between different physical hosts.

My interpretation suggests that there seem to exist two different kinds of software routing: (1) Embedding a real time operating system on an actual router. (2) Writing application layer code on a PC that can handle packets being transmitted between different virtual machines running on that very PC. Is this correct?

Upvotes: 0

Views: 105

Answers (2)

Halfabee2
Halfabee2

Reputation: 39

Performance of the link from the virtual network to the physical eventually becomes important at any reasonable scale. You're right that, within the same physical host, things can be pretty quick, but that requires that one can get everything needed in one box.

While merchant silicon has come a long way in improving the performance of networking equipment, greater gains are taking place getting CPU's to handle networking tasks better. Both AMD and Intel have improved their architectures to the point where 10 Gbps forwarding is a reality. Intel has developed a specialized library (DPDK Wiki Page) that takes care of a lot of low-level networking functions at high performance.

Upvotes: 1

ducducgoos
ducducgoos

Reputation: 21

It depends on what your router is doing. If it's literally just looking at a static route table and forwarding packets out another interface, there isn't much hit in performance.

It's when you get into things like NAT, Crypto, QoS, SPI... that you will see performance degradation. Hardware vendors are usually using custom silicon to process the more advanced features, this allows for higher throughput packet forwarding.

Now that merchant silicon is fast enough and the open source applications are getting better, the performance gap is closing.

It really depends on your use case as far as what you want to use. I've gone with both and not seen performance hits, but the software versions weren't handling high throughput workloads.

Upvotes: 1

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