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Where does ISR 1000 series router come in the timeline of ISR router segment? How different is it from ISR G1/G2?

Cisco Employee
Cisco Employee



I am trying to understand CISCO product line up.

And in which I am going through the router lineup, specifically ISR routers

So i understood, ISR G1 (1800, 2800, 3800) was rolled by cisco initially,

and then cisco rolled out next generation devices under the category ISR G2 (800, 1900, 2900, 3900), which were more powerful than its predecessors and came to market as their replacement.

Then the latest ones in the ISR segment is ISR 4000 series routers (4200, 4300, 4400), which are more powerful than ISR G2.


Below image shows the evolution of ISR routers-




I also came across a series called ISR 1000 under ISR segment (1111x, 111x, 1101 and 1109). Would like to know, where in the timeline of ISR devices does this fall into? And how does performance compare with G1/G2/4k?

8 Replies 8

Leo Laohoo
Hall of Fame
Hall of Fame

@dalakshm wrote:

Would like to know, where in the timeline of ISR devices does this fall into? And how does performance compare with G1/G2/4k?

The ISR 1100 is the direct replacement for the 800-series router (and because Cisco has ran out of numbers for the new model).  There is no way to compare the 1100 with the 4400 in terms of bandwidth, memory, CPU and network modules.  

The ISR 1100 was first announced in 1Q of 2018.


Hi leo,


Thanks for the response.

So for all the variants of ISR G2 except ISR 800 (ie, 1900, 2900, 3900), ISR 4k has replacements (4200, 4300, 4400)

And for (ISR 800) - (ISR 900 and ISR 1000s) are the replacements.

Did I understand it right?


Thanks and regards,

Darshan L.

ISR G2 will be replaced by the ISR 4K
The 800-series router will be replaced by the ISR 1K (to be confused with the ASR 1K).

Hi Leo,


Even ISR 800 series fall under ISR G2 only is it?


Thanks and regards,

Darshan L.

Yes and no.

Newer series platforms generally offer more "performance" for the series they replace. This means for the same traffic load, a newer "lower" model series might replace an older "higher" series model. Also, Cisco sometimes adds new models, also offering more performance, to an existing series. These might preclude the need to upgrade to a "higher" series at all.

So, it boils down to, whenever selecting a Cisco router, select what you need to meet your service requirements. I.e. avoid thinking a 29xx should be replaced by a 42xx or a 39xx should be replaced by a 43xx.

With Cisco's new "boost" licenses for the 4xxx ISRs, you might be able to "downsize" a model even more, as the full capacity of the router is available. I.e. what might have required a 44xx might only now require a 42xx.

@Joseph W. Doherty wrote:
Yes and no.

For what part of my conversation did you mean, "yes and no"?


Thanks and regards,

Darshan L.

If you believe there's a one-for-one series replacement. For example, an 1100 series might replace an 800, 1900, 2500, 2600, etc. series model. Although you can say different series are targeted at different market segments.

Timelines introductions are simple, but again, sometimes Cisco keeps a series alive by introducing new models in the series and there's often much overlap when you look at "performance". The "boost" license in the 4000 ISR series, makes a huge difference in where you might use different models.

Joseph W. Doherty
Hall of Fame
Hall of Fame
As Leo notes, the 1000 series, along with perhaps the 900 series, is a possible replacement for the 800 series although they haven't been discontinued yet, I believe.

As to performance, it depends on comparing actual models; often there's some overlap but the higher series models often offer hardware options not available in the lower series models. For example, the 800, 900 and 1000 series aren't too modular.
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