What is the advantage of Layer 3 switch over the Router ??
Best Answer
In general, layer-3 switches move packets faster (near line rate) because everything they do is in hardware. They tend to be cheaper and cheaper to operate (power, personnel, etc.) vs. a comparable router.
This does come with significant limitations, however...
reduced route table size
no NAT
no firewall and very limited security features
limited routing protocol support, if any.
possibly no IPv6 support at all (and that's not something that can be fixed with software) Granted that should be rare today. What I regularly see is IPv6 features substantially subtracting from IPv4 features.
Routers are predominantly designed to run routing protocols that regularly alter the path of traffic. They also handle numerous high-touch features such as NAT, QoS, security, VRF, etc. Outside the high-end market, routers are partially or totally software platforms.
For example, it's easy to take a commodity PC with a few NICs, load linux on it, and *poof* it's a router. No matter how much you hit it with the spice-weasel, it'll never be a switch.
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.
Best Answer
In general, layer-3 switches move packets faster (near line rate) because everything they do is in hardware. They tend to be cheaper and cheaper to operate (power, personnel, etc.) vs. a comparable router.
This does come with significant limitations, however...
Routers are predominantly designed to run routing protocols that regularly alter the path of traffic. They also handle numerous high-touch features such as NAT, QoS, security, VRF, etc. Outside the high-end market, routers are partially or totally software platforms.
For example, it's easy to take a commodity PC with a few NICs, load linux on it, and *poof* it's a router. No matter how much you hit it with the spice-weasel, it'll never be a switch.