I believe the issue will become a moot point in the next 12 months when vendors begin to ship switches with TRILL. TRILL is basically a layer 2 routing protocol that will replace spanning tree. It will allow you to connect several uplinks, utilize all the bandwidth of the uplinks, prevent loops, and find the best path to the destination through the switch fabric. Think of it like OSPF for layer 2. It should be shipping within the next 6 to 9 months. -----Original Message----- From: Raj Singh [mailto:raj.singh@demandmedia.com] Sent: Thursday, November 12, 2009 11:49 AM To: 'nanog@nanog.org' Subject: Layer 2 vs. Layer 3 to TOR Guys, I am wondering how many of you are doing layer 3 to top of rack switches and what the pros and cons are. Also, if you are doing layer 3 to top of rack do you guys have any links to published white papers on it? Thanks, Raj Singh