Please enable JavaScript.
Coggle requires JavaScript to display documents.
DESIGNING A NETWORK TOPOLOGY, image, image, image - Coggle Diagram
DESIGNING A NETWORK TOPOLOGY
INTRODUCTION
What is Topology
A branch of mathematics concerned with those properties of geometric configurations that are unaltered by elastic deformations such as stretching or twisting.
It is a map of an internetwork that indicates network segments, interconnection points and user communities.
Purpose of Map
To show the geometry of the network, not the physical geography or technical implementation.
DESIGN THEMES
Hierarchy
Distribution layer of routers and switches
Implement policies and segment traffic
Demarcation point between the access and core layers of the network
Roles
Controlling access to resources for security reasons
Controlling network traffic
Allow core layer to connect sites that run different protocol while maintaining high performance
Redistribute between bandwidth-intensive access layer routing protocols and optimized core routine protocols
Improve routing-protocol performance
Summarize routes from access layer
Access layer
Connects user via lower-end switches and wireless access points
Provide access to the internetwork
Provide access into corporate internetwork
using wide-area technologies
ISDN
Frame Relay
Leased digital lines
Analog modem lines
Core layer of high-end routers and switches
Optimized for availability and performance
Provide optimal transport between sites
High-speed backbone of the internetwork
Reliable and adapt to changes quickly
Use routing features that optimize packet throughput
Optimize core for low latency and good manageability
Flat versus Hierarchy
Flat Loop Topology
Hierarchical Redundant Topology
Mesh design
Partial- Mesh Topology
Full-Mesh Topology
Partial-Mesh Hierarchical Design
Avoid Chains and Backdoors
Hub and Spoke Hierarchical Topology
Redundancy
The goal is to duplicate any required component whose failure could disable critical applications
Components
Router
Switch
Switches
Channel Service Unit (CSU)
Power supply
WAN trunk
Internet connectivity
Can be implemented
Inside individual campus networks
Helps to meet availability goals for users accessing local services
Between layers of the hierarchical model
On the edge of the enterprise network
Ensure high availability for Internet, extranet, and virtual private network (VPN) access
Disadvantage
Expensive to deploy and maintain, need to implement redundant topologies with care, select a level of redundancy that matches customer's requirements for availability and affordability
Modularity
Large network design projects and large networks in general consist of differents areas or modules
Should be designed using
Systematic
Top-down approach
Applying hierarchy and redundancy
Well-defined entries and exits
Network design should be organized
Protected perimeters
CHARACTERISTICS OF A GOOD NETWORK DESIGN
new additions cause only local change, to the directly-connected devices
your network can double or triple in size without major design changes
you already know how to add a new building, floor, WAN link, remote site, e-commerce service, and so on
troubleshooting is easy because there are no complex protocol interactions to wrap your brain around
CAMPUS TOPOLOGY DESIGN
Minimize size of bandwidth domains
Minimize size of broadcast domains
Use a hierarchical, modular approach
Provide redundancy
Mirrored servers
Multiple way for workstations
Reach a router
Off-net communications
Consists of
Campus access laye
Campus distribution layer
Campus core layer
SCALING SPANNING TREE PROTOCOL
Keep switched network small
Less and equal to seven switches
Use BPDU skew detection on cisco switches
Use IEEE 802.1w
Provide rapid reconfiguration of spanning tree
Known as RSTP
LANS
Virtual LANs
What is VLANs?
Belong to an administrative group
Used to constrain broadcast traffic
Emulation of standard LAN
Allows data transfer without traditional physical restraints placed on network
VLAN Designs
Two Switches with Stations Attached
Explanation
: Two switches that are not connected to each other. When either one station send broadcast, only the stations on the same network will received the broadcast.
Single Switch with Stations from Network A & B Attached
Explanation
: Instead of two separated physical LANs, both are implemented on a single switch. All broadcast, multicast, unknown-destination traffic from any station will be received by all stations
VLANs Span Switches
WLANs and VLANs
Facilitates roaming
Users remain in same VLANs and IP subnet as roaming, so there's no need to change addressing information
Make it easier to set up filters to protect wired network from wireless users
WLANs is often implemented as VLANs
WORKSTATION-TO-ROUTER COMMUNICATION
Listen for route advertisements (not a great idea)
ICMP router solicitations (not commonly used)
Proxy ARP (Not a good idea)
Default gateway provided by DHCP (better idea)
No redundancy (Use Hot Standby Router Protocol (HSRP) for redundancy)
