Cisco NCS 5508

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As of Feb 2016

Weighing in at 150 lbs and using enough electricity to keep you warm in winter, the NCS 5508 was introduced November 17, 2015.

NCS stands for Network Convergence System. Cisco makes it clear that this switch is intended as a datacenter (or cloud) aggregation device and not as a replacement for the CRS Internet core router. And the data sheet bares this out -- the device can hold 250,000 IPv4 TCAM routes, so not enough for a default-free table. It can also hold a large number of /32 host routes in CAM. It is clear that the data sheet offers no guidance on the amount of packet memory.

Thanks to Dale Carder for pointing to a NANOG post that pegs this as a Dune design. Since Dune uses packet memory external to the switch, the NCS 5508 should have gobs. But Cisco doesn't say. If the normal progression of information is followed, there will be a deep dive at Networkers in Spring 2016 that will expose more details.

It is interesting that the NCS 5508 device uses QSFP28 optical modules instead of CPAK. Perhaps this means something.

update October 2016

There is now an architecture white paper that makes many things clear. 4 GB of packet memory is on the line cards but external to the Jericho ASICs. Each ASIC has its own packet buffer. This is a VoQ design with heavy buffers on the input side and light buffers on egress. Target is 10 mS of buffer for every queue. Details in the paper, but different cards have different amounts of route memory.

Line cards for the 5508 come in regular and scale. Scale has TCAM for lots of routes external to the ASIC. The space required for the external TCAM reduces the number of ports that can be supported on each line card.

update March 2017

An updated architecture paper in December 2016 corrects some errors in packet forwarding rates per ASIC. So, read this one instead of the citation above.

Fixed format NCS 5501 and 5502 switches

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The 5501 1 RU switch has one Jericho/Dune ASIC. Single chip TOR class switches use a family member without crossbar connections called Qumran-MX. Variants are regular and scale. Regular has forty-eight 10 Gb/s ports and six 100 Gb/s ports. Scale has forty 10 Gb/s ports and four 100 Gb/s ports.

The 5502 2 RU switch has eight ASICs interconnected with a cross-bar fabric. Both regular and scale have 48 QSFP28 100 Gb/s ports.

October 2016 List prices

NCS-5501-SE $ 120,000.00 NCS5501 - 40x10G and 4x100G Scale Chassis
NCS-5501 $ 108,000.00 NCS5501 Fixed 48x10G and 6x100G chassis
NCS-5502 $ 480,000.00 NCS5502 Fixed 48x100G chassis
NCS-5502-SE $ 720,000.00 NCS5502 - 48x100G Scale Chassis