Industry View · Networking & Optical

When compute became cheap, the network became the bottleneck

The AI buildout has turned plumbing into a profit center. NVIDIA's networking arm alone booked $8.2 billion in a single quarter, Broadcom's AI revenue reached roughly $20 billion for FY2025, and hyperscalers are steering a ~$600-690 billion 2026 capex wave toward the switches, optics and cables that decide whether a million GPUs behave like one computer.

Demonstrated ROIROI Classification

Nvidia networking ~$31B FY2026; Arista/Cisco AI networking revenue with hard figures

Key Figures

$8.2B
NVIDIA networking revenue, one quarter (Q3 FY26), +162% YoY
NVIDIA / Futurum
~$25B
Optical components market in 2025, AI-driven record
Cignal AI
~$600B
Big-Five hyperscaler 2026 capex, ~75% to AI infrastructure
CreditSights / Introl
$3.25B
Marvell's acquisition of photonics startup Celestial AI (closed Feb 2026)
Marvell / Contrary

Value Chain

Switch silicon
The merchant-vs-captive war

Broadcom's Tomahawk 6 hit 102.4 Tbps and the company holds a commanding share of high-end switch ASICs, while NVIDIA and hyperscalers pursue captive designs.

Broadcom, NVIDIA, Marvell, Cisco Silicon One
Systems & fabric
Ethernet eats the back-end

Ethernet is overtaking InfiniBand in AI scale-out on cost and openness, lifting Arista, Cisco and white-box builders.

Arista, NVIDIA Spectrum-X, Cisco, Celestica
Optics & transceivers
800G to 1.6T in two years

AI east-west traffic is driving a record optics cycle, with 800G-plus optics jumping toward a majority of shipments by 2026.

Coherent, Lumentum, Innolight, Eoptolink
DSP & interconnect chips
Retimers, AECs and PAM4

The unglamorous chips between switch and port — DSPs, retimers and active copper cables — became a high-growth niche as port speeds climbed.

Marvell, Credo, Broadcom, Astera Labs
Co-packaged optics
The power-wall frontier

Putting optics in the switch package promises huge power savings; 2026 marks the first volume CPO ramp on both InfiniBand and Ethernet.

NVIDIA, Ayar Labs, Lightmatter, Celestial AI

01 · The thesis

The interconnect is now the scarcest layer in the AI stack

For a decade, networking was a cost to be minimized. AI inverted that. Training a frontier model means thousands of GPUs exchanging gradients every step; idle accelerators waiting on data are the most expensive idle assets in technology. As Jensen Huang put it, copper runs out at a meter or two, which is why NVIDIA, Broadcom, Arista and Cisco are all racing the same curve from 400G to 800G to 1.6T ports, and toward optics fused directly onto the switch. The economics are brutal and bifurcated. NVIDIA's vertically integrated NVLink-InfiniBand-Spectrum-X stack made it, by its own claim, the largest networking business in the world at ~$31B for FY2026. But Ethernet is clawing back the scale-out layer on cost and openness, Broadcom's merchant silicon is arming everyone else, and a cohort of photonics startups raised billions betting that light, not copper, moves the next generation of clusters.

The merchant-vs-captive war

Broadcom's Tomahawk 6 hit 102.4 Tbps and the company holds a commanding share of high-end switch ASICs, while NVIDIA and hyperscalers pursue captive designs.

Ethernet eats the back-end

Ethernet is overtaking InfiniBand in AI scale-out on cost and openness, lifting Arista, Cisco and white-box builders.

800G to 1.6T in two years

AI east-west traffic is driving a record optics cycle, with 800G-plus optics jumping toward a majority of shipments by 2026.

Retimers, AECs and PAM4

The unglamorous chips between switch and port — DSPs, retimers and active copper cables — became a high-growth niche as port speeds climbed.

The power-wall frontier

Putting optics in the switch package promises huge power savings; 2026 marks the first volume CPO ramp on both InfiniBand and Ethernet.

02 · The two clocks

Three timing pressures that separate the durable franchises from the momentum trades

The speed-transition clock is the fastest it has ever run. The industry is compressing the 400G to 800G to 1.6T migration into roughly two years, and Dell'Oro expects 1.6 Tbps switches to ship in volume in 2026, surpassing 5 million ports within one to two years — faster than the 800G ramp before it. Each step raises switch ASPs and the number of optical modules per system. The Ethernet-vs-InfiniBand clock is past midnight for InfiniBand's monopoly. NVIDIA's own Spectrum-X Ethernet is now out-shipping its Quantum InfiniBand, and 650 Group forecasts AI scale-out Ethernet revenue surging past $100B by 2030. The open Ultra Ethernet Consortium shipped its 1.0 spec in 2025, standardizing the features that close InfiniBand's performance gap. The co-packaged-optics clock is the wild card. After years of debate, 2026 is the first volume CPO ramp on both InfiniBand and Ethernet (Dell'Oro), led by NVIDIA's Quantum-X and Spectrum-X Photonics. Success adds multi-billions to the optics TAM and threatens the pluggable-transceiver business model; failure strands a lot of startup capital.

03 · Public players & exposure

Who routes through, who gets routed around

We plot the listed players on two editorial axes — how exposed each is to AI disruption, against how ready its data, brand and position are to be the answer. The figures in the table are sourced; the placement is our read.

04 · Private flagships

The AI-native challengers

The companies attacking this industry AI-first, with disclosed funding where available:

Ayar Labs

Builds TeraPHY optical I/O chiplets that let thousands of GPUs act as one system, targeting copper's power wall in scale-up fabrics; claims an industry-first 8 Tbps UCIe optical chiplet.

Lightmatter

Its Passage platform pushes edgeless optical I/O across the die; the L200 claims 200+ Tbps of bandwidth and up to 8x faster training on large models.

Celestial AI

Developed an optical 'Photonic Fabric' to move data and pool memory across racks with light instead of electricity; pursued a fuller rack-scale stack than chiplet-only rivals.

Credo Technology

Pioneered purple 'ZeroFlap' active electrical cables that link GPUs to switches more cheaply and reliably than optics for short reaches inside AI racks.

Astera Labs

Supplies retimers, smart cable modules and PCIe/CXL fabric switches that knit accelerators, CPUs and memory together inside AI servers.

Celestica

Shifted from pure contract manufacturing to designing its own 1.6TbE DS6000/DS6001 switches running open-source SONiC, courting hyperscalers that want merchant-silicon boxes.

05 · Signals

What moved, and what to watch

06 · The exposure read

Who’s defensible, who’s at risk

AI rewards clean, structured advantage and punishes friction. The line runs through who owns the data, the brand and the customer — and who is merely a step the technology can route around.

Sources

Where this comes from

The spend, and the payoff

AI networking revenue, run-rate by vendor

Most recent reported quarter or annual figure per company; NVIDIA and Broadcom are quarterly, Arista AI revenue and Credo total revenue annual. Source: company filings, Futurum, Chipstrat, CNBC. ($B)

Who's defensible, who's at risk

Defensible vs At Risk

Defensible

  • Merchant switch silicon (Broadcom, Marvell) — arms every hyperscaler and white-box builder regardless of which system vendor wins; Broadcom's AI revenue grew ~65% to roughly $20B in FY2025 with a $73B-plus AI backlog.
  • Optical component leaders (Coherent, Lumentum, Innolight) — the 800G-to-1.6T transition and rising module-per-GPU ratios drove the optics market to a record ~$25B in 2025; NVIDIA is locking in supply with multi-billion commitments.
  • Ethernet system vendors (NVIDIA Spectrum-X, Arista) — as Ethernet overtakes InfiniBand in scale-out, both ride a TAM that 650 Group sees exceeding $100B by 2030; Arista guided AI revenue to $3.25B in 2026.
  • Interconnect-chip specialists (Credo, Astera Labs) — active electrical cables and retimers turned a commodity niche into a high-growth story, with the AEC market alone forecast to reach ~$4B by 2028.

At Risk

  • Proprietary InfiniBand economics — even NVIDIA's Spectrum-X Ethernet now out-ships its Quantum InfiniBand; the lossless, locked-in fabric that defined early AI training is ceding the scale-out layer to open Ethernet on cost.
  • The pluggable-transceiver business model — if co-packaged optics ramps as Dell'Oro expects in 2026, optics fused into the switch could erode demand for the discrete modules that are today's largest optical revenue pool.
  • Photonics startups dependent on the capital cycle — Ayar Labs, Lightmatter and peers raised billions at rich valuations; with ~75% of a ~$600B capex wave concentrated in a handful of hyperscalers, any pullback or a faster incumbent CPO roadmap leaves them exposed.
  • Legacy enterprise networking margins — vendors whose franchise rests on slower campus and traditional data-center switching face share pressure as spend concentrates in AI back-end fabrics where merchant silicon and white-box boxes set the price.

The signals — how it unfolded

Mar 2025

NVIDIA unveils silicon-photonics switches

At GTC, NVIDIA announced Quantum-X (InfiniBand, 2H25) and Spectrum-X Photonics (Ethernet, 2026) co-packaged-optics switches, with an ecosystem spanning TSMC, Coherent, Corning and Lumentum.

Aug 2025

Cisco doubles its AI target

Cisco closed FY2025 with over $2B in AI infrastructure orders — double its original $1B goal — and guided toward roughly $9B of AI orders in FY2026 on triple-digit hyperscaler growth.

Dec 2025

Ultra Ethernet ships Spec 1.0

The Ultra Ethernet Consortium finalized its 1.0 specification, hardening open Ethernet as the standard for AI back-end networks against InfiniBand.

Dec 2025

Marvell agrees to buy Celestial AI

Marvell announced (alongside Q3 earnings) the acquisition of photonic-interconnect startup Celestial AI for a $3.25B base (up to $5.5B with earn-outs), closing Feb 2026 — incumbents buying their way into co-packaged optics.

Mar 2026

NVIDIA backs the optics supply chain

NVIDIA reportedly committed ~$4B to Lumentum and Coherent, and Ayar Labs closed a $500M Series E — capital flooding into the optics layer ahead of the 1.6T and CPO ramp.

Challengers to watch

Ayar Labs

Builds TeraPHY optical I/O chiplets that let thousands of GPUs act as one system, targeting copper's power wall in scale-up fabrics; claims an industry-first 8 Tbps UCIe optical chiplet.

Lightmatter

Its Passage platform pushes edgeless optical I/O across the die; the L200 claims 200+ Tbps of bandwidth and up to 8x faster training on large models.

Celestial AI

Developed an optical 'Photonic Fabric' to move data and pool memory across racks with light instead of electricity; pursued a fuller rack-scale stack than chiplet-only rivals.

Credo Technology

Pioneered purple 'ZeroFlap' active electrical cables that link GPUs to switches more cheaply and reliably than optics for short reaches inside AI racks.

Astera Labs

Supplies retimers, smart cable modules and PCIe/CXL fabric switches that knit accelerators, CPUs and memory together inside AI servers.

Celestica

Shifted from pure contract manufacturing to designing its own 1.6TbE DS6000/DS6001 switches running open-source SONiC, courting hyperscalers that want merchant-silicon boxes.

Exposure table

CompanyStanceThe sourced fact
NVIDIA NVDAFull-stack incumbentNetworking revenue reached $8.2B in Q3 FY2026, up 162% YoY, and ~$31B for the full fiscal year — by NVIDIA's account the largest networking business in the world (NVIDIA Q3 FY26 results; CRN).
Broadcom AVGOMerchant arms dealerAI revenue grew ~65% to roughly $20B in FY2025; its Tomahawk 6 switch delivers 102.4 Tbps and AI backlog exceeds $73B (Broadcom FY25 call; Futurum).
Arista Networks ANETEthernet pure-playFY2025 revenue hit $9.0B; AI networking revenue exceeded its $1.5B goal and management guided $3.25B of AI revenue for 2026 (Arista Q4 FY25 results; Chipstrat).
Cisco Systems CSCOIncumbent re-ratingAI infrastructure orders topped $2B in FY2025 (double the $1B target); management now targets ~$9B of AI orders in FY2026 (Cisco FY25 call; CRN).
Coherent COHROptics leaderHeld ~22.2% of the optical transceiver market in 2025, the single largest share, and is a core supplier of optical components for AI datacom (GMInsights).
Marvell MRVLCustom + opticsA rising share of revenue now comes from AI optics, and it acquired photonics firm Celestial AI for a $3.25B base (closed Feb 2026), up to $5.5B with earn-outs (Marvell; Contrary Research).
Credo Technology CRDOAEC breakoutFY2025 revenue more than doubled (+126%) to $436.8M; the active electrical cable market it pioneered is forecast to reach ~$4B by 2028 (Credo; CNBC/JPMorgan).
Lumentum LITELaser & opticsNamed in NVIDIA's reported ~$4B of optics commitments to Lumentum and Coherent in early 2026, and demoed a 1.6T Marvell DSP at ~16W at ECOC 2025 (TAMradar; Marvell).
Ayar Labs pvt-AYARCPO challengerRaised a $500M Series E in March 2026 at a $3.75B valuation (~$870M total), backed by NVIDIA, AMD and others, to scale co-packaged optics (Ayar Labs; TAMradar).
Lightmatter pvt-LMATPhotonic interconnectValued at $4.4B with ~$850M raised (Series D, late 2024); its Passage L200 claims over 200 Tbps of optical I/O bandwidth (Contrary Research).

Sources