[c-nsp] L2 or L3 Core using 3550-12G

[Volodymyr Yakovenko]

On Wed, Feb 16, 2005 at 09:04:38AM -0600, Church, Chuck wrote:
>Kevin,
>
>	If I'm reading this right, your 'current L2 cores with L3
>interfaces at the
>distribution switches' refers to the old devices, right?  If so, I think
>with some careful planning you can get this to work.  The 3550FX and 12G
>will support uplink fast/backbone fast, in addition to Rapid STP.  I've
>played with RSTP, and seen convergence times around 2 seconds (about the
>time it takes to determine an interface is down).  That's pretty close
>to OSPF (I don't believe the 3550s support sub-second OSPF hellos yet).
>Keep in mind that the 12G has a limit of 16 (I believe) VLAN interfaces.

There is hardware limit of 16 HSRP groups, but actual number of VLANs, 
which you can safely L3 terminate on 3550 is much higher. The 16 HSRP groups 
limit can be easily overcomed by HSRP group id reuse for different VLANs.

-- 
Regards,
Volodymyr.