[c-nsp] GSR and 3750 GE-LX link problem

[Gert Doering]

Hi,

On Tue, Jan 11, 2005 at 01:23:58PM -0800, Michael K. Smith wrote:
> > For local ping, this isn't necessary - the routers won't forward packets
> > if "no ip routing" is set, but that's not necessary to ping.
> 
> Are you sure?  I'm not sure how the 3750 deals with encapsulation without
> the underlying protocols enabled.  Does the ethernet interface encapsulate
> the traffic as a Layer 3 packet or a Layer 2 frame?  Is the encapsulation
> based solely upon the "no ip switchport" command on the 3750?

"no ip routing" doesn't mean "IP switched off".

It switches off IP *forwarding*, but the box will still do IP pracket 
processing as a host - no forwarding, no use of routing protocols, use 
of "ip default-gateway" to decide where to default-route packets (which 
is also what the boot monitor does when you boot from TFTP).

(I admit that I'm not sure about the 3750, but the basic principle
of "no ip routing" vs. "ip routing" is embedded so deeply into IOS that 
it would surprise me very much if the 3750 is different here).

gert

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Gert Doering - Munich, Germany                             gert at greenie.muc.de
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