Download Three-Layer Hierarchical Network Design

Three-Layer Hierarchical
Network Design
Cisco Layers
Core
Layer


Distribution Layer

Access Layer
Why Use This Network Model?
This model simplifies the task of building a
 Reliable


Scalable


Divide network into functional areas
High performance


Redundancy
Layer design to control congestion
Efficient Management and Troubleshooting

Easily isolate causes of network trouble
Access Layer
 Provides workgroup/user access to the network
 Also called
the desktop layer because it
focuses on connecting client nodes, such
as workstations to the network
 This layer ensure packets are delivered to end
users
Access Layer
The access layer serves a number of functions:
 Layer 2 switching
 Packets sent to switch port based on destination MAC
address
 QoS classification and marking and trust boundaries
 Address Resolution Protocol (ARP) inspection
 Virtual access control lists (VACLs)
 Spanning tree
 Power over Ethernet (PoE) and auxiliary VLANs for
VoIP
Access Layer
Access Layer Equipment
Distribution Layer




This layer is also called the workgroup layer
Combines the data received from the access layer
switches before it is transmitted to the core layer for
routing to its final destination
This layer ensures that packets are properly routed
between subnets and VLANs in your enterprise
Provides policy-based connectivity and controls the
boundary between the access and core layers
Distribution Layer
 Combination of
LAN or WAN links.
 Routing services between LANs and VLANs
and between routing domains
 Redundancy and load balancing.
 Broadcast domain control

Acts as the a dividing point between broadcast
domains
Distribution Layer
Distribution Layer Equipment

Cisco 4000, 4500 series router and switch





Layer 3 switching
Can upgrade without buying new router
Activate remotely with a license
Upgrade from 200Mbps to 400Mbps for example
Usually under 4 ports
Core Layer
 This
layer is considered the backbone of the
network
 This layer of the network does not route traffic
at the LAN
 No packet manipulation is done by devices in
this layer
 This layer is concerned with speed and ensures
reliable delivery of packets
Core Layer
 Combines the traffic from all
the distribution
layer devices, so it must be capable of
forwarding large amounts of data quickly
 Providing reliability and fault tolerance
 Scaling by using faster, but not more,
equipment
Core Layer
Core Layer Equipment

Cisco switches such as 7000, 7700, and 12000
 7000





7700





4, 9, 10, and 18 slots
550 Gbps bandwidth per slot
Up to 192 40 GE ports and 32 100 GE ports
Up to $20,000
6, 10, and 18 slots
1.3 Tbps bandwidth per slot
Up to 348 40 GE ports and 192 100 GE ports
Up to $50,000
12000


2.5 Tbps bandwidth per slot
Over $100,000
 Catalyst switches such as

6000, 5000, and 4000
6000
 Up to 384(10Gbps)
ports or 96(40Gbps) ports
 7.68 Tbps throughput switching performance
 Over $30,000
 T-1 and

E-1 lines
Used for voice applications
 Frame relay connections,
ATM networks,
Switched Multimegabit Data Service (SMDS)