Chapter 1 -Internetworking Basics Flashcards
What is a MAC address
Also known as a hardware address, it is burned right into the NIC.
Network Segmentation
Breaking up a really big network into a number of smaller ones.
Done by using bridges, switches and routers.
What are some common causes of LAN traffic congestion?
- Too many hosts in a broadcast or collision domain.
- Broadcast storms.
- Too much multicast traffic.
- Low bandwidth.
- Adding hubs for connectivity to the network.
Hubs
Connect network segments together.
Inexpensive way to connect a couple of PC’s together.
Can contribute to congestion on Ethernet network.
Routers
- Connect networks together.
- Route packets of data from one network to another.
- Breakup broadcast domains by default.
Broadcast Domain
The set of all devices on a network segment that hear all the broadcasts sent on that segment.
What are the two advantages of routers in a network?
- They don’t forward broadcasts by default.
2. They can filter the network based on Layer 3 (Network Layer) information such as IP address.
What are the four router functions in a network?
- Packet switching
- Packet filtering
- Internetworking communication
- Path selection
Internetworking
When routers connect two or more networks and use logical IP addressing.
Routing Table Map
Used by routers to make path selections and to forward packets to remote networks.
Switches
Used to add functionality to a network LAN.
Make LANs work better - to optimize it performance - providing more bandwidth for the LAN users.
Breakup collision domains by default.
Collision Domain
An Ethernet term used to describe a network scenario wherein one particular device sends a packet on a network segment at the same time another device on a network sends one. at his results in a collision forcing both devices to retransmit at different times.
Bridging
Reduces collisions within a broadcast domain.
Increases number of collision domains on a network.
Provides more bandwidth for users.
What are some advantages of using the OSI model?
- It divides the network communication process into smaller and simpler components, this aids in component development, design and troubleshooting.
- It allows multiple-vendor development through standardization of network components.
- It encourages industry standardization by defining what functions occur at each layer of the model.
- It allows various types of network hardware and software to communicate.
- It prevents changes in one layer from affecting other layers so development is not hampered.
What is the purpose of the upper layers of the OSI?
The top three layers define how the applications within the end stations will communicate with each other and with the end user.
What is the purpose of the bottom four layers of the OSI?
They define how data is transmitted end to end.
What network devices operate at ALL seven layers of the OSI?
Network Management Stations (NMSs)
Web and Application Servers
Gateways (not default gateways)
Network hosts
Application Layer
Layer 7
File, print, message, database, and application services.
Presentation Layer
Layer 6
Data encryption, compression, and translation services.
Session Layer
Layer 5
Dialog control
Transport Layer
Layer 4
End-to-end connection
Network Layer
Layer 3
Routing
Manages device addressing
Tracks the location of devices on the network
Determines the best way to move data
Transports traffic between devices that aren’t locally attached.
Data Link Layer
Layer 2
Framing
1. Provides the physical transmission of the data and handles error notification, network topology, and flow control.
- Ensures that messages are delivered to the proper device on a LAN using hardware addresses and will translate messages from the Network layer into bits for the Physical layer to transmit.
- Responsible for the actual unique identification of each device that resides on a local network.
Physical Layer
Layer 1
Physical Topology
Six Things to Know About Routers
- By default they will not forward broadcast or multicast packets
- They use the logical address in a Network layer header to determine the next hop router to forward the packet to
- Can use access lists, created by an administrator, to control security on the types of packets that are allowed to enter or exit an interface.
- Provide Layer 2 bridging functions if needed and can simultaneously route through the same interface.
- Layer 3 devices provide connections between virtual LANs(VLANs)
- Can provide quality of service (QoS) for specific types of network traffic.
