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I'm many years away from such topics but I don't remember this being the case, moreover specs for net equipment was (is) on pps with the details stating usually
by gbil 2y ago
I'm many years away from such topics but I don't remember this being the case, moreover specs for net equipment was (is) on pps with the details stating usually 2-3 packet size categories. I'm interested on some reference on what you wrote
- Hikikomori 2y agohttps://www.fmad.io/blog/what-is-10g-line-rate https://www.fmad.io/blog/what-is-10g-line-rate As the article calls it, the gold standard. If a device is capable of forwarding/switching packets at the smallest packet size line rate on all interfaces at the same time you don't have to think too much about its performance when designing your network. Haven't worked much with hardware for a few years but it was common that Cisco switches were not capable of this.
- Dylan16807 2y agoGold standard sure, but that doesn't make it the definition of line rate.
- nsteel 2y agoVendors I've seen usually use one of a few "standard" packet size mixes e.g. imix. Nobody uses smallest size frames because nobody can hit their headline perf numbers for that, and it's not representative of real-world usage anyway. https://en.m.wikipedia.org/wiki/Internet_Mix https://en.m.wikipedia.org/wiki/Internet_Mix
- Hikikomori 2y agoI think this applies more to firewalls used for simple internet connections than switches/routers.
- nsteel 2y agoI was specifically talking about enterprise/core routers where the packet processing can be non-trivial and small frames hurt performance.
- Hikikomori 2y agoWhat core routers uses imix?
- nsteel 2y agoNot sure what you mean, but an example of using imix to measure perf of a core router is Cisco 8000 series https://miercom.com/wp-content/uploads/2024/02/Performance-Validation-for-Cisco-8000-Series-DR230428E-13Feb2024-.pdf https://miercom.com/wp-content/uploads/2024/02/Performance-V...
- Hikikomori 2y agoThat 8200 for example is capable of line rate at the smallest packet size so that imix marketing is kinda useless. When evaluating these kinds of devices this is what matters. IMIX makes sense on devices that are not capable of small packet line rate like firewalls where bandwidth is much more costly and need to be sized appropriately.
- nsteel 2y agoI don't have any Cisco core routers, not have I personally tested any, but that document I provided found their Q200 ASIC (in the 8000 series) required at least 170B frames to hit line rate: > Both DUTs can achieve line rate performance on all ports with an NDR of 170 Bytes for the 88-LC0-36FH-M line card and 215 Bytes for 8201-32FH router. Same values were observed for both IPv4 and IPv6 traffic. This exceeds all real-life deployments requirements regardless of position in the network. The 9000 series analysis reports something like 400B packets to hit line rate. Fundamentally, everyone has to scale their internal bus width and clock rate to hit the headline numbers, always at the cost of small frame performance.