"unsupported" features in IOS ("mpls mtu") (was: Re: [c-nsp] High Availability PoP Design)

[Johannes Resch]

On Thu, November 3, 2005 15:33, Saku Ytti said:
>
>  Also as of 12.2(25)S you can't have bridge-group and MPLS in same
> physical interface under different logical interface. In older IOS' it's
> no
> problem and it works. There is (was) no documentation that support has
> been
> removed in release notes. Rationale is, that it was never supposed to be
> working.
>  Kind of reminds me when VPND was removed between 12.2(14)S3 and S5 or so,
> without hint (as it shouldn't have been there any way, but worked).

since you mentioned some cases of sudden disappearance of features without
notification and between minor releases of a IOS train:

another example is the upcoming removal of support for "mpls mtu <x>" for
x being larger than 1500 byte on PA-FE (which did work just fine so far)
in the 12.2S train (confirmed at least on c7200) - great fun!

ciscos rationale is (you may have guessed it) that it was never officially
supported / supposed to be working in the first place.

if this particular upcoming change is a problem for anybody else than us,
please drop me a mail off-list - maybe we can bundle efforts.

regards,
-jr