Cisco ISR4351 vs C8300-2N2S-6T
The Catalyst C8300-2N2S-6T is the modern replacement for the end-of-sale ISR 4351, delivering roughly 10 Gbps of aggregate forwarding versus 1.5 Gbps, a faster x86 data plane, and native Cisco SD-WAN. For mid-size branch refreshes, migrate to the C8300-2N2S-6T.
Cisco ISR 4351
2RU mid-range ISR 4000 router with three NIM and two SM slots for high-density branch services.
- Up to ~1.5 Gbps aggregate throughput
- 3 onboard GE ports, 3 NIM slots, 2 SM slots
- Runs IOS XE with SD-WAN overlay support
- End-of-sale; on the Cisco end-of-life timeline
Cisco Catalyst 8300 Edge Platform
2RU high-performance edge platform with dynamic core allocation that succeeds the ISR 4351.
- ~10 Gbps aggregate forwarding (data-plane heavy mode)
- 6 onboard GE ports, 2 NIM and 2 SM slots
- Cisco IOS XE SD-WAN with edge compute / app hosting
- Current platform with active support and roadmap
Cisco ISR 4351 vs Cisco Catalyst 8300 Edge Platform: spec comparison
| Spec | Cisco ISR 4351 | Cisco Catalyst 8300 Edge Platform |
|---|---|---|
| Form factor | 2RU | 2RU |
| Onboard ports | 3x GE | 6x 1GE (4x RJ45 + 2x SFP) |
| NIM slots | 3 | 2 |
| Service module (SM) slots | 2 SM | 2 SM |
| Aggregate throughput | Up to ~1.5 Gbps | Up to ~10 Gbps (CEF aggregation) |
| Default DRAM | 4 GB | 8 GB (expandable) |
| Default flash | 4 GB | 8 GB |
| Data plane | Multicore (QFP-class) | x86 multicore, dynamic core allocation |
| Software | Cisco IOS XE | Cisco IOS XE SD-WAN / SD-Routing |
| Edge compute / app hosting | Via UCS-E SM modules | Native container app hosting |
| Lifecycle status | End-of-sale / migrate | Current / actively sold |
Choose Cisco ISR 4351 if
Choose the ISR 4351 only to extend an existing in-support fleet or to keep three populated NIM slots and SM modules you already own at sub-1.5 Gbps sites.
Choose Cisco Catalyst 8300 Edge Platform if
Choose the C8300-2N2S-6T for new purchases and refreshes that need real performance headroom, SFP uplinks, native SD-WAN, and edge compute in the same 2RU footprint.
Verdict
For a refresh, move from the ISR 4351 to the Catalyst C8300-2N2S-6T. It delivers a large throughput jump to roughly 10 Gbps, adds SFP uplinks and native app hosting, and keeps you supported. Keep the 4351 only short-term to preserve a third NIM slot or existing support coverage.
Frequently asked questions
How much faster is the C8300-2N2S-6T than the ISR 4351?
The C8300-2N2S-6T can aggregate up to roughly 10 Gbps of forwarding versus about 1.5 Gbps on the ISR 4351, a multi-fold increase driven by its x86 multicore data plane and dynamic core allocation.
Does the C8300-2N2S-6T have SFP uplinks?
Yes. Its six onboard ports include two SFP ports alongside four RJ45 GE ports, where the ISR 4351 provided three RJ45/SFP combo GE ports onboard.
Is the ISR 4351 still supported?
The ISR 4351 is end-of-sale and progressing through Cisco's end-of-life milestones. Plan migrations to the Catalyst 8300 to remain within software and hardware support.
Can I reuse my SM modules on the Catalyst 8300?
The C8300-2N2S-6T retains two SM slots, and many SM-X and UCS-E modules carry forward, but always confirm specific module support on the Catalyst 8300 datasheet before reusing hardware.
More ISR comparisons
Specs are for planning and may change; Uniqcli confirms the current Cisco bill of materials and pricing on your quote. Cisco, Catalyst, Nexus, Meraki, and Firepower are trademarks of Cisco Systems, Inc.; Uniqcli LLC is an independent authorized Cisco partner.