Cisco ISR 4331 vs Catalyst 8300
The Catalyst 8300 is the modern successor to the ISR 4331: it delivers several times the throughput, native SD-WAN and SASE readiness, and a longer support runway. Stick with the ISR 4331 only if you have an existing fleet and modest branch needs; choose the Catalyst 8300 for any new mid-to-large branch deployment.
Cisco ISR 4331
Popular 1RU ISR 4000 branch router for small-to-midsize sites, now in its sunset phase.
- System throughput around 100 Mbps to 300 Mbps (boost license)
- 3 GE WAN/LAN ports plus 2 NIM and 1 SM-X slot
- Runs IOS XE; supports SD-WAN with the right license
- Reaching end-of-sale/end-of-life milestones
Cisco Catalyst 8300
Modern IOS XE edge platform for medium-to-large branches with SD-WAN and SASE built in.
- CEF throughput up to ~18.8 Gbps, IPsec up to ~8.6 Gbps
- Multi-core x86 with crypto offload and container hosting
- Native Cisco SD-WAN and SASE integration
- 1RU and 2RU models with NIM, SM-X, and PIM slots
Cisco ISR 4331 vs Cisco Catalyst 8300: spec comparison
| Spec | Cisco ISR 4331 | Cisco Catalyst 8300 |
|---|---|---|
| Series | ISR 4000 | Catalyst 8300 |
| Form factor | 1RU | 1RU or 2RU |
| Aggregate/CEF throughput | ~100 Mbps base, up to ~300 Mbps boost | Up to ~18.8 Gbps |
| IPsec VPN throughput | Hundreds of Mbps range | Up to ~8.6 Gbps |
| Onboard interfaces | 3x GE (RJ45/SFP) | Up to 2x 10GE + multiple GE (model dependent) |
| Module slots | 2x NIM, 1x SM-X | NIM, SM-X, and PIM (model dependent) |
| SD-WAN | Supported (IOS XE SD-WAN) | Native, SASE-ready |
| Container / app hosting | Limited | Yes (multi-core x86) |
| Software | Cisco IOS XE | Cisco IOS XE |
| Lifecycle status | End-of-sale / approaching EOL | Current, full support |
Choose Cisco ISR 4331 if
Choose to keep the ISR 4331 only if you already own a fleet, your branch bandwidth needs stay in the low-hundreds-of-Mbps range, and you are not yet ready to refresh. There is little reason to buy new ISR 4331 units given lifecycle status.
Choose Cisco Catalyst 8300 if
Choose the Catalyst 8300 for any new medium-to-large branch: it scales to multi-gigabit CEF and gigabit-plus IPsec, adds native SD-WAN/SASE and app hosting, and has a far longer support runway than the ISR 4331.
Verdict
The Catalyst 8300 is the clear upgrade path from the ISR 4331, with roughly an order-of-magnitude more throughput, modern SD-WAN/SASE integration, and ongoing support. Migrate to the 8300 for new deployments and refresh cycles; only keep the ISR 4331 short-term where existing investment and low bandwidth needs justify deferring the upgrade.
Frequently asked questions
Is the Catalyst 8300 a replacement for the ISR 4331?
Yes. The Catalyst 8300 is Cisco's modern successor to ISR 4000 branch routers like the 4331, offering much higher throughput, native SD-WAN/SASE, and a longer support lifecycle.
How much faster is the Catalyst 8300 than the ISR 4331?
The gap is large. The ISR 4331 runs in the low-hundreds-of-Mbps range, while the Catalyst 8300 reaches up to about 18.8 Gbps CEF and roughly 8.6 Gbps IPsec, depending on model and licensing.
Is the ISR 4331 end of life?
The ISR 4331 has hit end-of-sale and is moving through end-of-life milestones. New branch deployments should target the Catalyst 8300 instead.
Do the ISR 4331 and Catalyst 8300 run the same software?
Both run Cisco IOS XE, which eases migration. The Catalyst 8300 adds stronger SD-WAN/SASE integration and application hosting on its multi-core x86 architecture.
More Routing comparisons
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