IOS family naming

Philip Davis pdavis at
Tue Jan 26 21:27:08 UTC 2010

Not sure how relevant this still is, but it explains some of the older ones.

On 1/26/2010 4:21 PM, Arie Vayner wrote:
> Andrey,
> I could not find a good link, but let me give you some info on SG, SGA, EW
> and EWA.
> All these trains are for the 4500 family (including 4900). They are just
> different generations.
> The EW (and then EWA) were the older trains for 4500, which were replaced by
> the SG trains.
> If I am not too wrong EW/EWA was new around 2004.
> SGA was the 1st release for the SG train, but later releases are not called
> SGB/SGC, but are just marked SG, so you get 12.2(31)SGA as the first release
> (with 12.2(31)SGA1, 12.2(31)SGA2 etc being maintenance releases, with SGA11
> scheduled to be released in a few weeks).
> The later SG releases are numbered as 12.2(37)SG, 12.2(40)SG, etc - and we
> have 12.2(53)SG as the latest one. Each such release brings in new features,
> and has its own maintenance releases (so it would be 12.2(53)SG1,
> 12.2(53)SG2 etc, with 12.2(53)GS2 being scheduled for the Q2CY10)
> Hope this gives you a better view.
> Arie
> On Tue, Jan 26, 2010 at 10:35 PM, Andrey Gordon <andrey.gordon at>wrote:
>> Hi List,
>> Anyone recalls ever seeing the IOS naming convention document. In
>> particular
>> I'm interested in differences between families and trains.
>> This is all I found:
>> But im looking for something a bit more recent maybe? Can figure out
>> differences between say SG, SGA, EW and EWA.
>> A link to the cipher would certainly help.
>> -----
>> Andrey Gordon [andrey.gordon at]


Philip Davis
Systems Administrator
I-2000 Inc.
(616) 532-8425

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