« The Cisco Catalyst 2940, 2950, 2900XL, and 3500XL Series switches are Layer 2 (L2) switches that can support only one Switch Virtual Interface (SVI) in the UP state at any one time. If additional VLANs are created, they can pass traffic without any issues. However, the SVI for new VLANs will not be UP. This is simply a hardware limitation. »

Donc pas possible d'avoir, sur un même switch, deux IP dans deux VLAN / préfixes d'interco différents.