Network Sales and Services Handbook (Cisco Press Networking Technology)
Figure 19-11 illustrates a redundant LAN and WAN infrastructure.
Figure 19-11. Redundant Network #1
The redundant components in this configuration are as follows:
Dual and diverse Ethernet network segments are used.
Dual NICs are used, with each card attaching to one of the diverse Ethernet network segments.
Each Ethernet network segment is attached to a Cisco Catalyst Switch; such as the 6000 Series.
Each Catalyst switch is served by two WAN routers.
Each WAN router is attached to the network service provider:
- Cisco's HSRP creates a single (virtual) address to which the LAN devices connect, enabling two or more Cisco routers to be viewed as a single router interface to the LAN.
- The same network service provider can be used for the redundant WAN link, or a second (diverse) network service provider can be used to provide this redundant link.
- Both the primary and redundant WAN link can be connected to the same WAN router, but this configuration makes the WAN router a single point of failure and therefore should be carefully considered.