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Layer 2 vs. Layer 3 to TOR



Hej,

Am 12.11.2009 21:04 Uhr schrieb Raj Singh:
> We are actually looking at going Layer 3 all the way to the top of rack and
> make each rack its own /24.

what a waste of IPs and unnecessary loss of flexibility!

> This provides us flexibility when doing maintenance (spanning-tree).

If you use a simple setup for aggregation, you do not need xSTP. Even including
redundancy, RTG (big C: flex-link) will be sufficient. Spanning the L2 over more
than one rack is dirty when you do L3 on the TORs, because you need to build a
Virtual Chassis or VPLS tunnels (not sure if EX4200 does that as of today).

> Also, troubleshooting during outages is much easier by using
> common tools like ping and trace routes.

Oh, c'mon. Yes, Layer 2 is a wild jungle compared to clean routing, but tracing
isn't that magic there. You have LLDP, mac-address-tables, arp-tables...

> I want to make sure this is something other people are doing out there and
> want to know if anyone ran into any issues with this setup.