Web OS 10.0 Application Guide
Chapter 1: Basic IP Routing 29
212777-A, February 2002
For example, consider the following topology migration:
Figure 1-1 The Router Legacy Network
In this example, a corporate campus has migrated from a router-centric topology to a faster,
more powerful, switch-based topology. As is often the case, the legacy of network growth and
redesign has left the system with a mix of illogically distributed subnets.
This is a situation that switching alone cannot cure. Instead, the router is flooded with cross-
subnet communication. This compromises efficiency in two ways:
nRouters can be slower than switches. The cross-subnet side trip from the switch to the
router and back again adds two hops for the data, slowing throughput considerably.
nTraffic to the router increases, increasing congestion.
Even if every end-station could be moved to better logical subnets (a daunting task), competi-
tion for access to common server pools on different subnets still burdens the routers.
This problem is solved by using Alteon Web switches with built-in IP routing capabilities.
Cross-subnet LAN traffic can now be routed within the W eb swi t ches wi t h wire s peed Layer 2
switching performance. This not only eases the load on the router but saves the network
administrators from reconfiguring each and every end-station with new IP addresses.
Admin/Sales
Server
Subnet
Router
Switch
Staff/Eng2
Switch
Eng/Staff2/Sales
Switch
FDDI
Internet
Web Switch
Admin. Subnet
Server
Subnet
Hub
Staff Subnet
Hub
Eng. Subnet
Hub
Internet
FDDI Router