Switch – When is a layer 3 switch more appropriate than a router in a branch office

designlayer3routerswitch

It seems that as time passes, vendors have added almost all the features of a router to a layer 3 switch.

For branch office deployments, how do other people who design networks choose between deploying a router + a layer 2 switch vs deploying just a layer 3 switch?

Best Answer

Layer 3 switch doesn't provide the typical edge features used on a router:

  • NAT/PAT (along with IPv4->IPv6 transition technologies)
  • Stateful Firewall
  • HQoS for multiple classes of traffic at a rate Ethernet is shaped/policed on the ISP side (usually you'll get subrate service, not full bandwidth of the Ethernet port connected to the device)

That said, for the inter-vlan routing in most of the scenarios the L3 switch will perform better and cause less problems, as small/edge routers are still using CPU to route the traffic and performance may be not ideal.

So propably you'll want L3 switch and edge router.

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