Cisco C1121-4P is the exact ordering identifier covered here, in the 1000 Series Integrated Services Routers range. The reviewed specification records wan ports: 2 x Gigabit Ethernet WAN; lan ports: 4 x Gigabit Ethernet LAN; routing throughput: Up to 1600 Mbps IPv4 forwarding, autonomous mode, 512-byte packets. Use this guide to decide what to include in a configuration request, rather than treating similar model numbers as interchangeable.
Specifications that define this model
The values below retain the source qualifiers. A missing field is not evidence that a capability is included or absent.
| Specification | Recorded value |
|---|---|
| WAN ports | 2 x Gigabit Ethernet WAN |
| LAN ports | 4 x Gigabit Ethernet LAN |
| Routing throughput | Up to 1600 Mbps IPv4 forwarding, autonomous mode, 512-byte packets |
| IPsec throughput | Up to 500 Mbps, autonomous mode, 512-byte packets |
| Power supplies | External AC power supply |
How to evaluate this exact configuration
WAN connections
WAN connections for C1121-4P: 2 x Gigabit Ethernet WAN. Check the carrier handoff and whether any connections share a combo port. Record the required optics or copper connection explicitly rather than buying by family name.
Routing rating
Routing rating for C1121-4P: Up to 1600 Mbps IPv4 forwarding, autonomous mode, 512-byte packets. Preserve the stated test conditions. Forwarding and encrypted traffic are different workloads; include packet sizes, services and resilience needs in the sizing request.
IPsec rating
IPsec rating for C1121-4P: Up to 500 Mbps, autonomous mode, 512-byte packets. Compare this figure with the encrypted workload, not only the circuit speed. Confirm the software and licensing needed for the intended deployment.
Compare nearby ordering codes
| Model | WAN ports | Routing throughput | IPsec throughput |
|---|---|---|---|
| C1121-4P | 2 x Gigabit Ethernet WAN | Up to 1600 Mbps IPv4 forwarding, autonomous mode, 512-byte packets | Up to 500 Mbps, autonomous mode, 512-byte packets |
| C8131-G2 | 1 x 1GE RJ-45; 1 x 1GE RJ-45/SFP combo | Up to 1.9 Gbps forwarding (512-byte packets) | Up to 1.5 Gbps (512-byte packets) |
| C8235-E-G2 | 2 x 1/10GE SFP+; 2 x 2.5GE mGig RJ-45 | Up to 19 Gbps forwarding (512-byte packets) | Up to 5 Gbps (512-byte packets) |
These are specification comparisons, not statements that the models are drop-in replacements. Compare the configuration limits before choosing an alternative.
C8131-G2 manufacturer reference · C8235-E-G2 manufacturer reference
Questions before you request a quote
Which product does C1121-4P identify?
It identifies Cisco ISR 1000 four-port Gigabit branch router. Keep C1121-4P on the requirement and quote; a family name alone does not fix the ordering configuration.
What should I check before ordering C1121-4P?
Start with the specification and configuration checks above, then state the quantity, destination and intended connections or platform. Ask for the exact contents of the offered configuration and identify every proposed substitution separately.
Build a clear requirement
Specify C1121-4P, quantity and delivery country, then add the configuration information discussed above. Keep accessories and any accepted alternative as separate lines. Request current pricing and availability rather than relying on an article for live commercial information.
View the C1121-4P product listing · Browse Cisco routers · Request a quote
For the wider selection process, read the related buying guide.
Sources and scope
Document and identifier checks: 2026-10-17. Prepared from manufacturer documentation and the catalogue's recorded specifications; no hands-on benchmark is claimed. Confirm destination-specific options and configuration eligibility against the source documents. Prices, stock, delivery dates and coverage terms are not established by this guide.