Information Technology Reference
In-Depth Information
Other chapters of this topic cover the other functions in the list.
For small office/home office (SOHO) env ironments, the entire hierarchy collapses to inter-
faces on a single device. Remote access to the central corporate net work is through tradi-
tional WAN technologies such as ISDN, Frame Relay, and leased lines. You can implement
feat ure s s uch as dial-on- demand rout ing (DDR) and stat ic rout ing to cont rol co sts. Remote
access can include virtual private network (VPN) technology.
Ta ble 2 - 2 summarizes the hierarchical layers.
Ta b l e 2 - 2
Cisco Enterprise Architecture Model
Hierarchical
Layer
Description
Core
Fast transport
High reliability
Redundancy
Fault tolerance
Low latency and good manageability
Avoidance of slow packet manipulation c aused by filters or other
processes
Limited and consistent diameter
QoS
Distribution
Policy-based connectivity
Redundancy and load balancing
Aggregation of LAN wiring closets
Aggregation of WAN connections
QoS
Security filtering
Address or area aggregation or summarization
Departmental or workgroup access
Broadcast or multicast domain definition
Routing between VLANs
Media translations (for example, between Ethernet and Token Ring)
Redistribution between routing domains (for example, between two differ-
ent routing protocols)
Demarcation between static and dynamic routing protocols
