[c-nsp] Re: malloc failures disabling dCEF on GSR

[Adam Chappell]

On 03/08/05, Adam Chappell <adam.chappell at gmail.com> wrote:
> Does anyone on this list have practical experiences of dealing with
> low memory situations on a GSR?

Thanks very much to all who suggested the use of "exception memory
fragment" and family to set a limit on minimum amount of contig memory
available.  It appears to be in 12.0.27Sx on the GSR at least, and
I'll investigate the use of this to resolve the problem.

A related note on disabling dCEF on the GSR, based on my experiences,
is that often ISIS (if used as an IGP) often still operates in these
situations since it runs over CLNS.

This can be quite disastrous since the downed GSR, unable to forward
without CEF, is still happily talking ISIS to neighbouring routers and
attracting traffic which is just blackholed.

"external overload signalling" within the ISIS router configuration
appears to instruct ISIS to deliberately break if CEF is also broken
which at least prevents traffic being sunk.

-- Adam.