Nokia 7750 SR Series Hardware Technical Reference — Chassis, Modules and Part-Number Compatibility

1. 7750 SR-a Series — Compact Shallow-Depth Platform, FP3 Silicon

The 7750 SR-a family consists of shallow-depth chassis optimized for 300 mm ETSI cabinets, powered by FP3 forwarding silicon. Supported modules are exclusively IOM-a and MDA-a / MDA-a-XP. SR-a hardware cannot accept IOM / MDA modules from SR-e, legacy SR-12e or SR-s platforms. Control processors, power supplies and fan trays are chassis-specific and non-interchangeable between SR-a4 and SR-a8. SR-OS runs PAYG port licensing bound to the chassis unit, not to individual plug-in modules.

SR-a MDA-a Standard Daughter-Cards

SR-a MDA-a-XP High-Speed Daughter-Cards

SR-a Series Chassis Spare Parts & Accessories

2. 7750 SR-e Series — Mid-Size Modular Platform, FP3 Silicon

The 7750 SR-e platform includes SR-1e, SR-2e and SR-3e chassis based on FP3 forwarding silicon. Hardware consists of IOM-e carrier mother-boards paired with MDA-e / MDA-e-XP daughter-cards. IOM-e and MDA-e modules are physically incompatible with SR-a, legacy SR-7 / SR-12 / SR-12e and SR-s platforms. SR-OS licensing for L2 / L3 service capabilities is bound to each individual IOM-e module rather than the chassis.

3. Legacy 7750 SR Platform — SR‑1, SR‑7, SR‑12, SR‑12e (FP3 / FP4 Silicon)

The original legacy 7750 SR family includes SR‑1, SR‑7 and SR‑12 chassis. SR‑12e is not a new physical chassis shell: it represents an upgraded operational state of existing SR‑12 hardware by replacing SFM switch‑fabric boards and installing CPM5 controller sub‑modules. SR‑7 can also be upgraded to SR‑7e mode. SR‑1 is a fixed‑configuration compact unit with integrated controller hardware and cannot be upgraded to “e” mode. Legacy IOM, IMM and MDA hardware is physically incompatible with SR‑a, SR‑e and SR‑s platforms.

3.1 CPM Controller Sub‑modules & SF/CPM Switch‑Fabric Boards

• CPM4: Not a separate removable sub‑module. Controller logic is integrated onto SFM4‑7 and SFM4‑12 combined SF/CPM boards. Supports FP3 modules only; FP4 line‑cards are not recognised.
• CPM5 PN: 3HE08423AA: Hot‑pluggable controller sub‑module for SR‑7e / SR‑12e; supports both FP3 and FP4 forwarding modules and modern SR‑OS releases.

3.2 SFM Switch‑Fabric Boards

• SR‑7 native: SFM4‑7 (integrated CPM4)
• SR‑7 upgrade to SR‑7e: SFM5‑7 (accepts CPM5 sub‑module)
• SR‑12 native: SFM4‑12 PN 3HE05948AA (integrated CPM4, FP4‑incapable)
• SR‑12 upgrade option‑1: SFM4‑12e, supports CPM5 for SR‑12e operation
• SR‑12 upgrade option‑2: SFM5‑12e PN 3HE08421AA high‑performance fabric for SR‑12e
• Mini‑SFM5‑12e PN 3HE08422AA: reduced‑capacity variant of SFM5‑12e

3.3 Legacy IOM / IMM Line‑Cards

Definition: IOM = MDA carrier mother‑board without native front‑panel ports. IMM = fixed‑port integrated media module.

FP3 Line‑Cards (works on native SR‑7 / SR‑12 with SFM4‑7 / SFM4‑12)

FP4 High‑Performance Line‑Cards (Requires SR‑7e / SR‑12e with SFM5‑7 / SFM5‑12e + CPM5. Not recognised by legacy SFM4‑12)

4. 7750 SR‑s Series — Next‑Generation High‑Density Platform, FP4 / FP5 Silicon

The 7750 SR‑s family represents Nokia’s latest high‑capacity routing hardware, built upon FP4 and FP5 forwarding silicon. SR‑OS software CLI maintains backward‑compatibility, but mechanical form‑factors are fully redesigned. IOM‑s, MDA‑s, XMA‑s modules are completely non‑interchangeable with SR‑a, SR‑e and legacy SR‑12e hardware. SR‑7s and SR‑14s support mixed deployment of FP4 and FP5 IOM‑s cards within a single chassis.

Module naming convention for SR‑s hardware:

• IOM‑s / IOM2‑se: Main carrier mother‑boards
• MDA‑s / MDA2‑se / XMA‑s / XMA2‑s: Port daughter‑adapters, supporting up to 800GE QSFP‑DD including DCO coherent optical interfaces.

Typical use‑cases for SR‑s: IP core backbone peering, large‑scale BNG subscriber gateways, line‑rate hardware‑accelerated DDoS mitigation, high‑density 100G‑400G‑800G data‑center gateway deployment, ANYsec and MACsec encrypted services.