Review - Chapter 2 Flashcards
Campus Network Structure
The portion of an enterprise infrastructure that interconnects end devices to services such as intranet resources or the Internet
Hierarchical Network Design
Addresses the sizing needs of most campus networks, and simplifies campus network design by allowing focus at different layers that build on each other
Hierarchical Network Layers
○ Core
○ Distribution
○ Access
Core
○ AKA backbone
○ Aggregates the campus networks and provides interconnectivity to the data center, the WAN, and other remote networks
Distribution
○ Aggregates the access layer switches, wiring closets, floors, or other physical domains by leveraging module/Layer 3 switches
○ May aggregate the WAN connection at the edge of the campus and provides policy-based connectivity
Important distribution considerations
□ Availability
□ Fast path recovery
□ Load balancing
□ QoS
Access
Used to grant user access to network applications and functions and generally incorporates switched LAN devices with ports that provide connectivity
Access Layer Capabilities
□ High availability
□ Convergence
□ Security
Enterprise Campus Architecture
The traditional hierarchical campus network applied to network design which divides the enterprise into physical, logical, and functional areas while leveraging the hierarchical design
Layer 2 Forwarding Table
○ AKA MAC table
○ Contains MAC addresses and destination ports
○ Destination MAC is referenced in the MAC table and frame is forwarded to the destination ports specified in the table
ACLs
Switches apply ACLs based on MAC and IP addresses
○ Generally only higher-end switches support both
○ Layer 2 support ACLs only with MAC addresses
Content-Addressable Memory (CAM)
○ MAC tables use CAM
○ Extremely fast access and allow for line-rate switching performance
○ Only supports 0 or 1 results
○ Useful for Layer 2 forwarding tables
Ternary Content-Addressable Memory (TCAM)
○ ACL and QoS tables are housed in TCAM
○ Extremely fast access and allow for line-rate switching performance
○ Provides 0, 1, and don’t care results
○ Useful for building tables for searching longest matches (i.e. IP routing tables organized by prefix)
○ Stores ACL, QoS, and other information generally associated with upper-layer processing
Three planes of operation in Distributed Hardware Forwarding
○ Management
○ Control
○ Forwarding
Cisco Switching Methods
○ Route caching
○ Topology-based switching
