[afnog] VLANs on Cisco Catalyst 2950

[Bruce Zamaere]

Guys,

I can't do "switchport trunk encapsulate dot1q" on my switch

"switchport trunk ?" doesn't list encapsulate as an option.

I'm running 12.1(13) IOS on a catalyst 2950 Series. Further to this I
still don't seem to get this working too! I've tried everything I can
think of but naah! just doesn't seem to work! The frustration is that
I have managed to get this to work before using HP Switches. Ok now
here's a really dumb question.

If I am on the switch through a console cable. I have set up ip on
each vlan interface why can I ping interfaces on the same switch? I
thought this would be ideal for troubleshooting purposes. How does the
IOS actually use the VLAN interfaces if they are shutdown? I find this
a bit confusing to be honest.

Finally is there a way to trick or to force the IOS to bring up more
that one VLAN at once? I noted 2 or three other people had asked a
similar question on posts on the net but the question wasn't
satifactorily answered. I'm asking this cause on some cisco vlan
configs I came across the "no shutdown" command was issued on the vlan
interfaces. Is the problem I am facing just a Catalyst 2950 problem???

On 5/26/06, Mark Tinka <mtinka at africaonline.co.zw> wrote:
> On Friday 26 May 2006 10:29, Bruce Zamaere wrote:
>
> > interface FastEthernet0/24
> >
> >  switchport trunk allowed vlan 101-103
> >
> >  switchport mode trunk
> >
> >  no ip address
>
> As Patrick suggests, .1q is probably a good idea - we like (to
> be) "open" :-).
>
> conf t
>  int fa0/24
>   switchport trunk encapsulation dot1q
>
> > At the moment I have to host on ports 1 and 24 with IPs on
> > their respective subnets. I can only ping the switch when the
> > vlan in question is brought up! Also from the switch I can't
> > ping the host or the interface unless the vlan is brought up.
> > So if I can only have one vlan up at a time how should my
> > config / setup change?
>
> Well, assign an IP address to the switch that's in the same
> subnet as the router connected to trunk port 24. Then set a
> default route on your switch to the router. It's done the old
> way on this switch model:
>
> conf t
>  ip default-gateway n.n.n.n
>
> Be sure to have a corresponding management VLAN up/up on the
> switch.
>
> Just out of curiousity, why would you like direct Layer 3
> reachability switch from all VLANs, especially since you'll
> probably be working in only one of them most of the time?
>
> If, for some reason, you require Layer 3 reachability from the
> switch from any VLAN, you can do so through the router. The
> switch doesn't have to have all VLAN interfaces for that to
> happen.
>
> Cheers,
>
> Mark.
>
>
>