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C891F-K9 real-world speeds; 1Gbps Ethernet GPON


I have a 1Gbps optical Ethernet circuit that performs at around 980Mbps peak when a laptop is directly connected to the GPON.

The 891F is rated at 51.2Mbps, or 100KPPS x 64B x 8b with no services enabled. An increase in packet size to 1500 puts maximum performance at 1.2Gbps. With NAT and ZBFW enabled, the router is unable to push past 200Mbps and the CPU maxes out at 99%. With ZBFW disabled, it inches closer to 450Mbps while the CPU remains just under 50%. This is WAN (L3 Gi8) to LAN (SVI) to a desktop (L2 Gi0).

RFC 2544-based performance puts the 890 series at 1.4Gbps with 1500-byte packets. The same document claims 54Mbps with firewall enabled, or 75Mbps with PAT and I can achieve double that in real-world tests with both enabled.

Is this all the 891F is able to muster? Obviously I don’t expect this router to handle NAT, ZBFW, IPSEC, QoS, and a ton of other services enabled and still approach 1Gbps, but it’s hard to believe it can’t handle close to 1Gbps with just NAT and ZBFW enabled. I realize it’s not apples-to-apples, but an off-the-shelf NETGEAR or ASUS router can handle those speeds easily with NAT and firewall enabled.

Tested with the same results on 15.4(1)T1 and 15.4(3)M5.

I’m in a weird spot where I have the hardware in-hand but SMARTnet has not activated and TAC won’t answer even simple questions without a contract. Our AM, SE and VAR have all checked out for the weekend - I don’t blame them. Curious if anyone here has any more detail than I do or something I haven’t already looked up and found.


2 Replies 2

Leo Laohoo
VIP Community Legend VIP Community Legend
VIP Community Legend

Is this all the 891F is able to muster?

How you're able to squeeze >100 Mbps from an 891F is impressive.  

Cisco will never allow the cheapest router to push 1 Gbps. 

To push 1 Gbps, look at 4451.

I wouldn't be surprised if the limitation was partly artificial. Whether it is or isn't, 1Gbps is rather ubiquitous in the enterprise space both on the WAN and LAN side. You would think the new "top tier" would be 10Gbps+ if they were to limit the branch office field either via hardware or software.

My initial purchase was based on experience with an 1811 that could do 80% port speed (~80Mbps on a 100Mbps interface) and the older 2009 router performance report. If the 890 series could do 100KPPS at 1500 bytes, 1Gbps should have been feasible.

After this disappointment, I went back and looked at some additional data and Miercom reports. It seems at the "low end" you'd need a 3925E (~1.6Gbps with NAT IMIX), ISR 4431 w/ 1Gbps license, ISR 4451, or an ASA 5516-X to reasonably expect ~1Gbps with NAT and firewall features enabled. Could potentially squeeze it out of a 2951, but at this point I'm skeptical enough to shoot higher to ensure results.

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