What Cisco Won’t Tell You About ISR G1 vs. G2 Routers | Curvature
New Ask the Expert Video: What is Cisco Meraki Mode?
Learn what Cisco Switching choices you have with Curvature today!

What Cisco won’t tell you about ISR G1 vs. G2 Routers

Recently, Cisco has been pushing clients to adopt their next-generation edge router platform (ISR Gen2, 1900/2900/3900). You may have already been contacted by your Cisco Account Manager to discuss ways to move you from your current-gen infrastructure of ISR Gen1 (1800/2800/3800). Granted, the newer platform is incredibly fast and very powerful – but what, exactly, are you gaining from pursuing such an upgrade?

There are certainly some valid reasons to move to the ISR G2s.  The following is a transcript of an interview with one of our lead engineers that really dives into this decision from a technical standpoint:

Q:  Are there situations that call for network engineers to implement the ISR G2s over the ISR G1s?

A:  Absolutely. However – these are required much more rarely than most think.  For these small routers, selection really comes down to throughput requirement and what physical interfaces are needed.  For connections under 100Mbps an 1800 or 2800 is more than powerful enough.  If throughput requirement is 100mb-500mb the 1900 or 2900 are a good fit (although we can typically also offer a 3800 that will suffice at huge pricing discount in these cases).  For connections over 500mb, a 3900 is the way to go.

Q:  As these are typically utilized as edge routers? Aren’t organizations typically using connections under 100mb?

A:  That’s right – and that is why the ISR G1s (1800, 2800, and 3800) are such a great fit.  At 1/3 the cost of the G2s, the G1s suffice for most environments when connections are 100mb or less.

Q:  Are there any other instances when organizations should consider a G2 over a G1?

A:  Yes, as I mentioned, physical interfaces required can be the other driver, although these are rarely needed. If an organization needs an EHWIC-ESG or 4G Wireless WAN module, then the G2 is needed, but outside of that, there is no major physical interface advantage for the G2 over the G1.

Q:  Tell me about software options between the two.

A:  The last release for the G1 is 15.1(4)M which is a feature rich, robust software with minimal bugs.  It is very rare that features of 15.2 software are needed; but this is a consideration (albeit rare). It’s also worth mentioning that the software for the G2s is still proving to be quite buggy, and as the G1 software is so much more mature, there is a stability advantage. I will also add that if a client is running Call Mrg Express or Unity Express, I would recommend the G2, as those features are heavily license-key and software dependent, and keeping them under SMARTnet is critical.

Q:  When will SMARTnet be dropped on the G1s?

A:  SMARTnet support will stop in November, 2012. However, our Netsure can offer superior support at a fraction of the cost. and we will support these as long as organizations need. Folks can find good info on Netsure at www.curvature.com/third-party-maintenance.


Think of your home network for a moment. More than likely, you have a cable or xDSL modem connected to a router, which then connects your devices via a Gigabit NIC (1,000 Mbps).  Depending upon the level of service you pay your ISP for, that modem will give you anywhere from ~1Mbps to ~5Mbps.  If Intel were to suddenly offer a 10 Gigabit NIC and tell you how incredibly powerful and fast the new NICs are, you’d likely be unimpressed, because the bottleneck of your connection is and will likely remain at that 1-5Mbps speed.  Would you pay to “upgrade?”  Of course not.

When Cisco introduced the 1900, 2900, and 3900 series routers, they included some serious performance increases, but most users will never see or benefit from this performance increase as these are typically used for T1 or T3 connections.  Say you are using a 2811 with 6 T1 lines (using VWIC’s to maximize density); each T1 is 1.54Mbps for a total of 9.24Mbps.  Now, the 2811 provides 61Mbps throughput (2821=87Mbps and 2851=112Mbps). Then your Cisco rep comes along and suggests that you rip out this existing infrastructure and deploy 2911s instead going forward as they offer an impressive throughput increase to 180Mbps.  Would you do it to take advantage of that throughput increase?  What if it also meant rendering your previous WIC & NM investments obsolete, requiring you to buy new interface cards to get throughput that you won’t see?  What if it also meant moving to Universal IOS with requiring keys to unlock functionality of the router?

So, in summary: 1800s, 2800s, and 3800s are and will continue to be available through Curvature as long as they are useful to you – they are a fraction of the cost of the G2s, and the G2s are rarely required from a technical standpoint. For connections over 100mb, you should look at a G2 (or a 3800), and over 500mb you should look at the 3900. If you are running Call Mrg Express or Unity Express or need one of the rare unique features of 15.2 software, you should look at a G2. For most purposes, these units are used for simple applications, and engineers just need these routers to do simple tasks and to do them well. In light of that, the G1s are a great fit – and when you couple that with the huge cost advantage and the software stability advantage, it just makes the G1s that much more interesting.

From a market standpoint, the 1800, 2800 and 3800s are typically available at over 75-80%+ discount from list price, while the 1900, 2900 and 3900s are closer to 50% discount from list price. Our stock is complete with both ISR G1s and G2s immediately available.

Throughput comparison chart: ISR G2 Series vs. Original ISR Series

For the most recent version of this Tech Guide, please visit: www.www.curvature.com/isr-g1-vs-isr4000

Twitter Facebook LinkedIn Instagram Youtube
2810 Coliseum Centre Drive Suite 600 28217 Charlotte, NC
+1(704)921-1620 [email protected]