Lenovo Flex System Fabric CN4093 Application Manual page 394

394
CN4093 Application Guide for N/OS 8.4
Take a closer look at the CN4093 in the following configuration example:
Figure 40. Switch‐Based Routing Topology
First Floor
10/100 Client Subnet
100.20.10.2-254
Primary Default
Router: 205.21.17.1
10 Gbps
Secondary Default
Router: 205.21.17.2
The CN4093 connects the Gigabit Ethernet and Fast Ethernet LAGs from various
switched subnets throughout one building. Common servers are placed on another
subnet attached to the switch. A primary and backup router are attached to the
switch on yet another subnet.
Without Layer 3 IP routing on the switch, cross‐subnet communication is relayed
to the default gateway (in this case, the router) for the next level of routing
intelligence. The router fills in the necessary address information and sends the
data back to the switch, which then relays the packet to the proper destination
subnet using Layer 2 switching.
With Layer 3 IP routing in place on the CN4093, routing between different IP
subnets can be accomplished entirely within the switch. This leaves the routers free
to handle inbound and outbound traffic for this group of subnets.
10/100 Client Subnet
10 Gbps
IF#2 IF#3
IF#1
Second Floor
131.15.15.2-254
Server Subnet:
206.30.15.2-254
IF#4