[c-nsp] Local switching on 12000

[Per Carlson]

Hi.

Does someone know if there are any plans for supporting local
switching of Ethernet VLAN to Ethernet VLAN on *different* ports
on the GSR (Eng3 LC)?

According to the RN (http://tinyurl.com/sxaqz) only Ethernet (Port
mode) to Ethernet VLAN is supported on different ports.

We have separate Ethernet domains (one with MST and one with
PVST+) that are terminated on different ports on a GSR.  This
works fine for L3-services because the Vlans never cross the
domain boundaries. But when trying to stich two Vlan's from the
two domains together, you need something that transports the
Ethernet-frames transparently between the two ports on the GSR.
The only way to do it (as I'm aware of) is using an EoMPLS tunnel.
But that requires two routers...

The Local Switching feature would suit nicely in this case.

Yes, I know that forwarding of BPDU's between the domains will
cause interesting behaviours (mildly). STP will be disbled on the
interfaces towards the GSR.

Merging the two domains and only run MST is of course the prefered
way (in the long run), but the path to get there is scattered with
a lot of obstacles... (If someone have a good recipy for doing
this transition, please let me know). 

-- Per Carlson, Sr. Network Developer