Cisco 2911 vs ISR4331
The ISR 4331 is the modern IOS XE replacement for the end-of-life Cisco 2911 (ISR G2), delivering much higher throughput, far more memory, and Cisco SD-WAN support in a 1RU chassis. Production 2911 routers should be migrated to the ISR 4331.
Cisco 2911 ISR G2
ISR Generation 2 branch router with three GE ports and four EHWIC slots on classic IOS 15.
- 3 onboard GE ports, 4 EHWIC slots, 1 ISM, 2 DSP slots
- 512 MB DRAM / 256 MB flash default (classic IOS 15)
- No native IOS XE or Cisco SD-WAN
- End-of-life; past last day of support
Cisco ISR 4331
Mid-range ISR 4000 branch router on IOS XE with NIM and SM slots and SD-WAN support.
- 3 onboard GE ports, 2 NIM slots, 1 SM slot
- 4 GB DRAM / 4 GB flash default
- Up to 2 Gbps aggregate throughput (license)
- Cisco IOS XE with Cisco SD-WAN support
Cisco 2911 ISR G2 vs Cisco ISR 4331: spec comparison
| Spec | Cisco 2911 ISR G2 | Cisco ISR 4331 |
|---|---|---|
| Onboard GE ports | 3 | 3 |
| Modular slots | 4 EHWIC + 1 ISM + 2 DSP | 2 NIM + 1 SM |
| Aggregate throughput | Tens to ~100 Mbps class (G2) | 100 Mbps to 2 Gbps (license) |
| Default DRAM | 512 MB | 4 GB |
| Default flash | 256 MB CF | 4 GB |
| Software | Cisco IOS 15 (classic) | Cisco IOS XE |
| Native SD-WAN | No | Yes (Cisco SD-WAN) |
| Voice / DSP | PVDM3 (2 DSP slots) | PVDM4 via NIM |
| Form factor | 2RU | 1RU |
| Lifecycle status | End-of-life | Mature but supported |
Choose Cisco 2911 ISR G2 if
Choose the 2911 only to keep an existing voice/branch site running on EHWIC and DSP modules you already own until a planned refresh; it is not viable for new purchases.
Choose Cisco ISR 4331 if
Choose the ISR 4331 for refreshes: dramatically higher throughput, 8x the DRAM, IOS XE, SM-slot expansion, and native Cisco SD-WAN in a smaller 1RU chassis.
Verdict
Migrate from the Cisco 2911 to the ISR 4331. The 2911 is end-of-life on classic IOS with limited memory and modest throughput, while the 4331 offers up to 2 Gbps, IOS XE, more memory, and SD-WAN in a 1RU box. Keep a 2911 only short-term where DSP/EHWIC modules and low bandwidth delay replacement.
Frequently asked questions
What is the replacement for the Cisco 2911?
The Cisco ISR 4331 is the modern replacement for the 2911, moving from classic IOS 15 with EHWIC/DSP slots to IOS XE, NIM and SM modules, much more memory, and Cisco SD-WAN support.
Does the ISR 4331 support voice like the 2911?
Yes. The ISR 4331 supports voice via PVDM4 DSPs on NIM modules and CUBE/SRST, replacing the PVDM3-based voice services of the 2911, though modules must be repurchased for the new slot type.
Is the Cisco 2911 end of life?
Yes. The 2911 reached end-of-sale in the 2017 to 2018 window and is past its last day of support, so it should be replaced to maintain a supported, patched software image.
Is the ISR 4331 faster than the 2911?
Significantly. The ISR 4331 scales up to 2 Gbps aggregate throughput with a performance license, well beyond the practical forwarding capability of the older 2911.
More ISR G 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.