Core layer

  • Cisco 6509.
  • Static routing used to ISP ( or basic BGP ).
  • FWSM or ACE module used as initial filter.
  • Static route down to VIP of aggregation layer FHRP.

Aggregation Layer

  • Cisco 6506 ( MSFC ).
  • Traffic received from core routed to CSM
  • CSM load balances to VLANs at the access layer
  • Simple Design allows inter-vlan routering ( web, app, db )
    • Inter-vlan routing without a FWSM can lead to access from the VLANs.

Access Layer

  • Cisco 6509
  • Servers typically devided into web, app, and database VLANS.
  • Server gateways set to CSM, FWSM, or VIP of the FHRP on L3.
  • Firewall restrictions between layers common.