MLS and L3 Switching

hclisschennai · ‎01-23-2009

Hi Everybody,

Can you anyone help me to understand what is the difference between L3 Switching & MLS (Multi Layer switching)

regards,

R.B.Kumar

Giuseppe Larosa · ‎01-23-2009

Hello R:B Kumar,

often the two terms are used.

MLS = multi layer switching refers to all the technologies that are used to perform forwarding at multiple levels of the OSI stack.

Traditional LAN switching is L2 switching.

To perform inter-vlan routing efficiently L3 switching has to be used that allow to build forwarding tables that provides efficiency.

But there are cases where the forwarding decision needs to be taken at an OSI layer above L3.

So we can say that L3 switching is the same as inter-vlan routing and that MLS is a more general framework.

Or also that L3 switching is a subset of MLS.

Actually in most scenarios the two can be seen as the same (if no server load-balancing is involved we are just doing L3 switching)

Hope to help

Giuseppe

Joseph W. Doherty · ‎01-23-2009

From http://www.cisco.com/en/US/tech/tk389/tk815/tk850/tsd_technology_support_sub-protocol_home.html, "MLS and Layer 3 switching are equivalent terms."

From http://www.networkdictionary.com/networking/ms.php, "Multilayer switching is simply the combination of traditional Layer 2 switching with Layer 3 routing in a single product. Multilayer switching is new, and there is no industry standard yet on nomenclature. Vendors, analysts, and editors don't agree about the specific meaning of terms such as multilayer switch, Layer 2 router, Layer 3 switch, IP switch, routing switch, switching router, and wirespeed router. The term multilayer switch seems to be the best and most widely used description of this class of product that performs both Layer 3 routing and Layer 2 switching functions."

Personally, I consider the terms more or less equivalent although I might consider a L3 switch has less features than a MLS without defination of what those features might be.

hclisschennai · ‎01-23-2009

Hi,

Thanks all. I appreciate your effort to make me to understand the concept.

The URLs provided is pretty good. Thanks again