Network Topologies and Types Flashcards
`Client-Server Network
- Some nodes act as clients
- Servers make resources and services available to clients
Peer-to-Peer Network
- Each end system acts as both client and server
- Services are distributed through a network
LAN
Local Area Network
- Confined to single geographical location
- Connected with cables or short-range wireless technologies
CAN
Campus Area Netowrk
- Large LAn that spans multiple nearby buildings
Datacenter
- Network that hosts only servers and storage, not end user client devices
WAN
Wide Area Network
- Network of network
- Connecteed with long-distance links
- Could be two or more large LANS or remote workers connecting over the internet
MAN
Metropolitan Area Network
- Smaller than WAN
- City-wide network encompassing multiple buildings
PAN
- Close range network links between variety of devices
- Internet of things
Network Topology
- Describes the flow of data through a network
Point to Point
- Single network link between two nodes
- Defined by the 1-1 relationship of the nodes
Star Topology
- Each endpoint is connected to central forwarding node, like a hub, switch or router
- Centrol node mediates communication between other nodes
- Most widely used
- Easy to configure because data flows through central node
Mesh Topology
- Full: every node having link to every other node
- Partial: Important devices interconnected to mesh with extra links for fault and redundancy.
Ring Topology
- Each node is wired to a neighbor in a close loop
- Each node passes information in one direction until it reaches its destination
- no longer used on LANs, but is still used on some WANs
- Double, counter-rotating rings can be used to provide fault tolerance
- Not used in many Lan’s anymore, but still used in many WANs
Physical Bus Topology
- more than two nodes share same bandwidth of the media.
- Only one node can be active at any time.
- All nodes attach to a single cable segment
Logical Bus Topology
- Nodes receive data transmitted all at the same time, regardless of wiring layout
- Only one node can transmit at same time
- All nodes in same collision domain
- When hub is deployed it is physical star-logical bus topology
Hybrid topology
- Mixture of, p2p, star, mesh, ring and bus.
Three Tiered Network Hierarchy
- Breaks down networks into smaller sections based on functions performed
- Access, Distribution, Core
Access/Edge Layer
- Allows end-user devices to connect to network
- Implemented with structured cabling and wireless access
- Connected to workgroup switches
- Connect in star topology
- No direct link between access switches
Distribution/Aggregation Layer
- Provides fault tolerant interconnctions between different access blocks and core
- Each Access Switch has full or partial mesh to each router or layer 3 switch in distribution block layer
- Often used to implement traffic policies like filtering and QoS
- Utilize layer 3 switches
Layer 3 Switch at distribution layer
- Usually have interfaces at 10 Gbps and backbone ports at 40 Gbps
- Uses ASIC(Application Specific integrated circuits)
- This makes layer 3 switches faster but less flexible.
- Do not perform WAN routing
- Only work with interior routing protocols.
- Often only support ethernet
Core Layer
- Provides highly available network backbone
- Provide redundant traffic paths for data to flow around other layers
- Routers and layer 3 switches in the core establish full mesh with switches in the distribution layer
STP
Spanning Tree Protocol
- Means for bridges or switches to organize themselves into hierarchy
- Switch at the top is the root (Switch with lowest ID, priority value and MAC address)
- Each switch then determines shortest path to root
Root Port
- Port that forwards up switch hierarchy to root switch
- Usually high bandwidth backbone or core switch
Designated Ports
- Ports that forward traffic down through network with least cost
Blocking Port
AKA non-designated port
- Port that would create a loop
Switching Loop
- Flooded frames circulate the network forever
- Will cause broadcast storm if uncorrected
Trunks
- Interconnections between switches
- VLAN IDs (VIDs) must be preserved for receiving switch to forward correctly
802.1Q
- VLAN traffic is identified with a tag inserted into the ethernet frame between Source Address and Ethertype fields.
Half Duplex
A node cannot transmit and receive at the same time
Full-duplex
Nodes can transmit and receive at the same time
Untagged Port
- If a port will only ever participate in a single VLAN, it can be configured as untagged
- Also know as access or host port
- Follows this logic:
No tag needs to be added to frame if it is addressed to same VLAN on same switch
If frame needs to transport over trunk line, apply 802.1Q tag and forward to trunk
If switch receives 802.1Q tagged frame on access port, strip stage before forwarding
Tagged Port
- Normally operating as trunk
- Capable of transporting traffic addressed to multiple VLANs
- Might connect switches or switch to router
- Possible that host attached port may need to be trunk, if it is hosting multiple virtual OSs which could be on multiple vlans
Voice or auxillary VLAN
- Distinguishes between PC and VoIP traffic without having to configure a port
VLAN
Virtual LAN
- Configuration of manages switches to isolate ports to separate broadcast domains
- Operates at layer 2