The third and final episode in the very popular series on where we attempt to discover what really happens inside your network device.

Although software will be at heart of network innovation for the next decade, it will still run on hardware and it’s time to expose the internals of our network hardware and understand the hardware architecture inside a typical device. Many people are surprised to find that CPUs, memory, storage and buses are similar to computers while the forwarding engines are rather spectacularly different.

Thanks to our guests for working very hard to bring this show to you. the-silicon-inside-your-network-part-3

Simon Chatterjee
John Harrington – Network Sherpa and @networksherpa

Chassis

Choice of Bus (stack), Crossbar, multi-stage fabric. (see attached document on hw/ evolution)
Multi-stage requires dedicated fabric and fabric interface ASICs, Clos networks (just hidden from view)
Important technology such as Virtual Output Queueing – Helps fix Head of line blocking.
Non-blocking? – Take half your ASIC ports and point them backwards to the fabric.

Hardware knowledge in the real world:

People familiar with to tradeoffs – SDM prefer for 3750
Commodity ASICs => better price but with more tradeoff and caveats => much more careful engineering.
Cisco Nexus 9K => Fantastic innovation. Take precious resources (forwarding tables) and make the Fabric ASIC do LPM and make the linecard ASIC do host routes.
OpenCompute- A great breakdown of the different technologies. – Pluggable modules / swappable CPUs etc.