1. Antonio González Torres
Switches
Antonio González Torres

2. Hierarchical Network Design
The design of larger LANs includes identifying the following:
An access layer that connects end users into the LAN
A distribution layer that provides policy-based connectivity between end-user LANs
A core layer that provides the fastest connection between the distribution points

3. LAN design goals
Functionality
Scalability
Adaptability
Manageability

4. Functionality
The network must work. The network must allow users to meet their job requirements. The network must provide user-to-user and user-to-application connectivity with reasonable speed and reliability.

5. Scalability
The network must be able to grow. The initial design should grow without any major changes to the overall design.

6. Adaptability
The network must be designed with a vision toward future technologies. The network should include no element that would limit implementation of new technologies as they become available.

7. Manageability
The network should be designed to facilitate network monitoring and management to ensure ongoing stability of operation.

8. LAN design considerations
The function and placement of servers
Collision detection issues
Segmentation issues
Broadcast domain issues

9. Server Placement Enterprise servers Workgroup servers
support all the users
should be placed in the main distribution facility (MDF).
Workgroup servers
support a specific set of users
should be placed in the intermediate distribution facility (IDF).

10. Segmentation
the process of splitting a single collision domain into smaller collision domains
reduces the number of collisions
allows for greater utilization of bandwidth
Using Layer 2 devices such as bridges and switches
Routers reduce the size of the collision domain and the size of the broadcast domain at Layer 3

11. LAN design methodology
Gather requirements and expectations
Analyze requirements and data
Design the Layer 1, 2, and 3 LAN structure, or topology 
Document the logical and physical network implementation

12. Availability measures
Availability measures the usefulness of the network.
things that affect availability:
Throughput
Response time
Access to resources
Every customer has a different definition of availability.

13. Design LAN Structure
The most common LAN topologies are star and extended star
The topology structure can be broken into OSI layers to determine devices to use

14. LAN design documentation
OSI layer topology map
LAN logical map
LAN physical map
Cut sheets
VLAN logical map
Layer 3 logical map
Addressing maps

15. Document Logical Diagram
the flow of data in a network
A snapshot view of all LAN implementation

16. OSI layer topology map
This diagram shows how the devices and telecommunication closets are connected

17. Cut sheets
Cut sheets store detail information about the different connections in the network

18. VLAN logical map
VLAN logical maps show the inter VLAN and Intra VLAN interconnection using a router or trunking ports

19. Layer 3 logical map
These diagrams show the logical addresses different devices use to send and receive information

20. Addressing maps
Addressing maps show the logical addresses configured for each network device

21. Layers design

22. Layer 1 Design
One of the most important components to consider when designing a network is the physical cabling.

23. Layer 1 Design Issue: Type of Cabling
copper or fiber-optic?
the overall structure of the cabling

24. Some rules on Cabling
Fiber-optic cable should be used in the backbone and risers in all cable designs.
Category 5e UTP cable should be used in the horizontal runs.
The cable upgrade should take priority over any other necessary changes.
Enterprises should also make certain that these systems conform to well-defined industry standards, such as the TIA/EIA-568-A specifications.

25. Star Topology Using Cat. 5 UTP

26. Typical MDF in Star Topology
In a simple star topology with only one wiring closet, the MDF includes one or more horizontal cross-connect (HCC) patch panels.
HCC patch cables are used to connect the Layer 1 horizontal cabling with the Layer 2 LAN switch ports.
The uplink port of the LAN switch, depending on the model, is connected to the Ethernet port of the Layer 3 router using a patch cable. At this point, the end host has a complete physical connection to the router port.

27. Multi-Building Campus
When hosts in larger networks exceed the 100-meter limitation for Cat. 5e UTP, more than one wiring closet is required.
Multiple wiring closets mean multiple catchment areas.
The secondary wiring closets are referred to as IDFs.

28. Extended-Star Topology in a Multi-Building Campus
VCC is used to interconnect the various IDFs to the central MDF.
IDFs should be connected to the MDF by vertical cabling, also called backbone cabling.
Fiber-optic cable is normally used because the vertical cable lengths are typically longer than 100 meters

29. Logical Diagram
the locations and identification of the MDF and IDF wiring closets
the network topology model without all the details of the exact installation paths of the cables
the basic road map of the LAN
the number of spare cables
the type and quantity of cables used to interconnect the IDFs with the MDF

30. detailed documentation of all cable runs, the identification numbers, and the port the run is terminated on at the HCC or VCC.

31. Devices at Layer 2 determine the size of the collision domains.
Layer 2 Design
Devices at Layer 2 determine the size of the collision domains. 

32. Asymmetric Switching
provides more bandwidth to vertical cabling, uplinks, and servers

33. The desired capacity of a vertical cable run is greater than that of a horizontal cable run.

34. Determine the number of 10 Mbps and 100 Mbps ports
review of the user requirements for the number of horizontal cable drops per room and the number of total drops in any catchment area.
This includes the number of vertical cable runs.
E.g.: four horizontal cable runs per room; total 18 rooms; require 72 LAN switch ports

35. Collision Domain Size with Hubs

36. Layer 2 Switch Collision Domains

37. An Acceptable Solution Using Hubs
Must make sure bandwidth to the host is provided in accordance to the specifications gathered in the requirements phase of the network design process

38. Layer 3 Design

39. Layer 3 Router for Segmentation
All data traffic from Network 1 destined for Network 2 has to go through the router.
There are two broadcast domains

40. Logical Addressing Mapped to the Physical Network
A standard convention should be set for addresses of important hosts on the network.

41. Address Map and Logical Network Map
provides a snapshot of the network

42. helps to troubleshoot the network
Physical Network Map
helps to troubleshoot the network

43. VLAN Environment
combines Layer 2 switching and Layer 3 routing technologies
limits both collision domains and broadcast domains
provides security with the creation of VLAN groups

44. Hierarchical LAN Design
easier to make changes to the network as the organization grows

45. Access layer switches
the entry point for user workstations and servers to the network
provides services such as VLAN membership.
Access layer functions also include MAC layer filtering and microsegmentation

46. Distribution layer Networks are segmented into broadcast domains
Policies are applied and ACLs can filter packets.
Switches in this layer operate at Layer 2 and Layer 3
Distribution layer functions:
Aggregation of the wiring closet connections
Broadcast/multicast domain definition
Virtual LAN (VLAN) routing
Any media transitions that need to occur
Security

47. Distribution layer
The following Cisco switches are suitable for the distribution layer: 
Catalyst 2926G
Catalyst 5000 family
Catalyst 6000 family

48. Core layer The core layer is a high-speed switching backbone.
If the switch does not have a router module, an external router is used for the Layer 3 function.
This layer should not perform any packet manipulation.
A core infrastructure with redundant alternate paths gives stability to the network
Asynchronous Transfer Mode (ATM) or Ethernet switches can be used.

49. Core layer
The following Cisco switches are suitable for the core layer:
Catalyst 6500 series
Catalyst 8500 series
IGX 8400 series
Lightstream 1010