Performance of layer 3 switches when they are acting like a router

[Alireza Karimi]

Hi everybody

I want to know what are the performance differences of layer 3 switches when they are acting just like a router with lots of route entries in their routing table in compare to when they are acting in layer 2?

The layer 3 switch in our case is “WS-C3750X-24T-S”

I guess there is a difference between these two situations:

1. when the switch is acting in layer 3 and just routes packet between different VLAN (in routing table we just have entries for connected interfaces and nothing else)
2. when the switch is acting in layer 3 and also has to do routing based on static routes or routes learned via a routing protocol

I think in situation 1 the switch performance is just like when it is acting in layer 2 but I don’t know about situation 2. Does anyone know about this?

Thanks a lot

[Vasilii Mikhailovskii]

Hello.

Actually there is no difference unless you reach a capacity limit of routing table and other TCAM entries.

Also you need to note that some IOSs do not support full (but stub only) EIGRP functionality.

PS: see details regarding routing capacity.

[Alireza Karimi]

Hi

Thank you so much Vasili. It was very useful.

Do you know the throughput of switch in terms of bits per second in routing template mode if we do not pass the limits that is mentioned in that link? Is it above 5 Gbps or not?

Best Regards