L3 and routing differences

[thaar_altaiey]

hi everybody,

can any one tell me about the real differences in L3 and router software features only (i dont want the differences between switch L3 and router).

v. thanks

thaar

[scottmac]

Your question is a bit broad, but in a nutshell: There is no difference. L3 routing is L3 routing regardless of the device you are using to do it.

The term "L3 Switch" is a marketing thing - it's still just a router (albeit a very fast one where most of the action is happening in silicon).

The difference used to be the WAN interfaces (on the router, not available on the switch)..... not true these days ... you can get a variety of WAN interfaces for an "L3 Switch" these days.

Now it's all just a matter of speed and architecture.

FWIW

Scott

[thaar_altaiey]

thanks for reply.

offcourse, i know these differences. the difference also the number of ports. But i think, in software, there are differences such as bandwith management, configuring routing protocols (BGP, OSPF ...etc), antivirus checking ...etc . I mean these differences (CatOS and IOS).

best regards

thaar

[jaregalado]

Hi

there´s an excellent discussion on the differences between Layer 3 switching and routing on the

Cisco LAN Switching book by Clark/Hamilton

http://www.amazon.com/exec/obidos/tg/detail/-/1578700949/qid=1102620504/sr=8-2/ref=pd_csp_2/102-5740912-7016945?v=glance&s=books&n=507846

this is the book to read I you really want to understand Cisco LAN switching.

Regards.

[sushilk]

Layer 3 Routing:

Devices involved in Layer 3 routing perform the following functions:

Packets are forwarded between networks based on Layer 3 addresses.

An optimal path is determined for a packet to take through a network to the next router.

Switching Functionality 11

Packet forwarding involves a table lookup of the destination network, next-hop router address,

and the router’s own outbound interface.

An optimal path can be chosen from among many possibilities.

Routers communicate with each other using routing protocols.

Layer 3 Switching:

Devices involved in Layer 3 switching perform the following functions:

Packets are forwarded at Layer 3, just as a router would do.

Packets are switched using specialized hardware, application-specific integrated circuits

(ASICs) for high-speed and low latency.

Packets can be forwarded with security control and quality of service (QoS) using Layer 3

address information.

Layer 3 switches are designed to examine and forward packets in high-speed LAN environments.

Whereas, a router might impose a bottleneck to forwarding throughput, a Layer 3 switch can be

placed anywhere in the network with little or no performance penalty.

[forsudhaji]

I feel we can compare L3 Routing and L3 Switching to that of the activities performed in Control Plane and Data Plane respec.