⚠ Growing Fast and Still Losing ShareHigh threat

Cisco Systems (CSCO) — threat to the moat

Cisco's data-centre Ethernet sales grew 77% in a quarter and Nvidia's grew 2.8 times, so Cisco fell further behind.

Cisco is growing in the data centre and losing ground at the same time. IDC's second-quarter 2026 data showed Cisco's data-centre Ethernet revenue up 77.3% to $2.24 billion1. In the same quarter Nvidia's Ethernet revenue grew 2.8 times and Arista's 37.9%2.

Ethernet revenue growth, Q2 2026 (% year on year)+36.2%Cisco, all Ethernet+77.3%Cisco data centre+37.9%Arista+180%NvidiaThe Next Platform on IDC Q2 2026 Ethernet data; Nvidia reported as 2.8 times, shown as +180%
Fast, and still slower than the leader.

In the first quarter of 2026 IDC put Nvidia first in data-centre Ethernet switching with 21.5%, Arista at 20.7% and Cisco at 17.8%3. The Competitors pages cover Nvidia and Arista one by one.

The Next Platform notes that IDC's figures exclude Cisco's sales of Silicon One chips to hyperscalers4, so Cisco's position in the largest data centres is somewhat larger than the switching share suggests.

Cisco's router business is the exception. In the same first quarter, when it was third in data-centre switching, its router revenue grew 24.4% and its router share was 35.1%5. The AI data centre needs both, and Cisco is stronger in the part that connects data centres than in the part inside them.

IDC's campus figures show the other half of Cisco's switching. Non-data-centre revenue was 60.5% of Cisco's switching total in the first quarter and grew 14.1%6. Cisco's switching business is still mostly a campus business that happens to have a fast-growing data-centre arm.

Still, a company that grows 77% and falls behind is in a market where it is not the default choice. The figure to watch is Cisco's data-centre share; if it falls below 15% while the market keeps growing, Cisco will be a participant in the AI build-out rather than one of its leaders.

References
  1. Third-party estimateIDC's second-quarter 2026 data showed Cisco's data-centre Ethernet revenue up 77.3% to $2.24 billion.
    The Next Platform on IDC's Q2 2026 Ethernet data - Cisco Ethernet $5.43bn (+36.2%), data-centre $2.24bn (+77.3%), Arista $2.3bn, Nvidia $3.86bn. — Q2 2026 · publ. 20 September 2026 · source ↗
  2. Third-party estimateIn the same quarter Nvidia's Ethernet revenue grew 2.8 times and Arista's 37.9%.
    The Next Platform on IDC's Q2 2026 Ethernet data - Cisco Ethernet $5.43bn (+36.2%), data-centre $2.24bn (+77.3%), Arista $2.3bn, Nvidia $3.86bn. — Q2 2026 · publ. 20 September 2026 · source ↗
  3. Third-party estimateIn the first quarter of 2026 IDC put Nvidia first in data-centre Ethernet switching with 21.5%, Arista at 20.7% and Cisco at 17.8%.
    DataCenterKnowledge on IDC 1Q26 - data-centre Ethernet switching shares: Nvidia 21.5%, Arista 20.7%, Cisco 17.8%. — 1Q26 · publ. 2026 · source ↗
  4. Third-party estimateThe Next Platform notes that IDC's figures exclude Cisco's sales of Silicon One chips to hyperscalers, so Cisco's position in the largest data centres is somewhat larger than the switching share suggests.
    The Next Platform on IDC's Q2 2026 Ethernet data - Cisco Ethernet $5.43bn (+36.2%), data-centre $2.24bn (+77.3%), Arista $2.3bn, Nvidia $3.86bn. — Q2 2026 · publ. 20 September 2026 · source ↗
  5. Third-party estimateIn the same first quarter, when it was third in data-centre switching, its router revenue grew 24.4% and its router share was 35.1%.
    IDC, Worldwide Ethernet switch and router tracker, 1Q26 - Cisco switching revenue $4.5B and 29.3% share, router share 35.1%. — 1Q26 · publ. 2026 · source ↗
  6. Third-party estimateNon-data-centre revenue was 60.5% of Cisco's switching total in the first quarter and grew 14.1%.
    IDC, Worldwide Ethernet switch and router tracker, 1Q26 - Cisco switching revenue $4.5B and 29.3% share, router share 35.1%. — 1Q26 · publ. 2026 · source ↗
Sources
Generated September 25, 2026