N10-009-Section_1 Flashcards
What does OSI stand for
Open Systems Interconnect model is a standard of the international organization for standardization (ISO) - General purpose framework that characterizes and standardizes how computers communication with
e another over a network. Each layer serves the layer above it and is served by the layer below it
What does ISO stand for
International Organization for Standardization
List the 7 layers of the OSI Model
Application, Presentation, Session (Upper layers), Transport, Network, Data-Link, Physical
Describe the Application Layer
- The Software
Describe the Presentation Layer
- How the Software packages the data to be sent out
Describe the Session Layer
- The connection session over which data is sent
Describe the Transport Layer
- Includes TCP/UDP, Port numbers
Describe the Network Layer
- IP Addresses, Routers
Describe the Data-Link Layer
- MAC Addresses, Switches
Describe the Physical Layer
- Ethernet Cables, Hubs
DLC
Data Link Control protocols. The category of layer 2 protocols that use MAC address to route info over a network. It defines how DLC organizes
What is TCP?
Transmission Control Protocol - A connection oriented protocol with a 3 way handshake
What is the TCP 3 way handshake
- Client will send a Syn packet to the server, 2. server will send back a SYN/ACK response,3. Client sends an ACK back to the server. The connection is established and will stay open until someone closes it
What is UDP?
User Datagram Protocol - Connectionless Protocol - Data is just sent, no verification
What is the IP Packet?
The IP part of an Ethernet Frame - Dest IP, Source IP, Dest Port, Source Port, Sequence, ACK, Data
What are PDUs?
Protocol Data Units - Parts of a Frame that are used in different protocols
Describe the Ethernet Frame
A chunk of data sent across an ethernet network - 1500 bytes - Dest MAC, Source MAC, Dest IP, Source IP, Dest Port, Source Port, Sequence, ACK, Data, FCS
What is the TCP segment?
Same as UDP Datagram, but used in TCP - Dest Port, Source Port, Sequence, ACK, Data
What is the UDP datagram?
Same as TCP segment, but used in UDP - Dest Port, Source Port, Sequence, ACK, Data
ASIC
An ASIC (Application-Specific Integrated Circuit) in networking is a specialized hardware chip designed to perform specific tasks efficiently, particularly related to network packet processing and forwarding. Unlike general-purpose processors, ASICs are purpose-built for high-speed and low-latency operations in networking equipment such as routers, switches, and firewalls.
NGFW
Next Generation Firewall. As opposed to a traditional firewall that only filters traffic based on port number an NGFW can filter traffic on the application level as well.
IDS
Intrusion Detection System - could be a computer or software - watches for suspicious activity on a network
IPS
Active IDS - Intrusion Prevention - The device/software will actually do something to stop/reject the intrusion
TCP Offload
Refers to the load balancing of TCP related tasks. A Load Balancer can distribute TCP tasks to a certain server allowing the other servers to handle the rest of the data
SSL Offload
Refers to the load balancing of SSL related tasks. A Load Balancer can distribute TCP tasks to a certain server allowing the other servers to handle the rest of the data
Load Balancer
A Load balancer can distribute traffic among several servers. It can also perform tasks like TCP and SSL offloading to take those tasks away from the servers themselves. Can also provide Caching so requests don�t always have to go to the servers, and traffic prioritization. Content Switching, application-centric balancing, certain requests always go to certain servers.
Proxy Server
Device or software that runs on a server that acts as an intermediary between 2 other parts of a network - provides caching, content filtering, access control, acts sort of like a firewall. Proxy Servers are application specific, Web Proxy, FTP proxy, VOIP proxy
Forward Proxy Server
Forward proxy will take requests or data from a client and forward it out - Clients are aware of the proxy. Clients will need to be configured to use the proxy - Hides the Client
Transparent Proxy
Is in-line between clients and the internet so there is no configuration, clients have to go through the proxy to get out
Reverse Proxy Server
Proxy server represents the web server and not the client - used to protect the server from malicious actors - Can balance the load for high volume sites - protect against DoS attacks - Hides the server
NAS
Network Attached Storage - file level storage
SAN
Storage Area Network - Block level storage - big brother of NAS
Wireless LAN Controller
A switch or some software that allows you to configure all of your Access Points at once
CDN
Content Delivery Network. A server that can cache large amounts of data so that users don�t have to stream data from across the world, the just stream from the closest CDN
VPN
An Encrypted Tunnel to a proxy server. VPNs use a Concentrator or Head-end for clients to connect to.
VPN Concentrator / Head-end
A dedicated device that acts as an endpoint for the network. Performs high-speed encryption/decryption
QoS
Quality of Service. Traffic Shaping or Packet Shaping, can prioritize and control traffic
TTL
Time To Live. A way to stop a task if its taking too long or in danger of causing a loop. Could be applied to cached materials. TTL is measured in hops, each router the packet passes through will decrease the TTL by 1
Routing Loops
Can happen especially with static routes. TTL can help to prevent this.
Elasticity
Cloud. Can scale up or down as needed very quickly
Multitenancy
Cloud. Many different clients are using the same cloud infrastructure
NFV
Network Function Virtualization. The virtualization of network hardware
VPC
Virtual Private Cloud - Your own little cloud, router/firewall, switch that all connect to the internet. You can use a VPN to connect to a VPC for more security
Transit Gateway
VPCs are connected with a Transit Gateway. A “cloud router”
VPC Gateway
A VPC gateway will connect your VPC to external networks or can facilitate communication between components inside the VPC. Two common Types of VPC Gateways are Internet Gatway (IGW, connects your VPC to the public internet) and Virtual Private Gateway (VGW, connects your VPC to an external private network like an on-prem data center)
VPC NAT Gateway
Allows VPCs to connect to the internet without exposing them to inbound internet traffic. Outbound traffic only.
VPC Endpoint
Direct connected between cloud provider networks. AWS to some other cloud provider.
NSL
VPC. Network Security List. Rules that can control access to VPCs based on protocols and ports. Lists are applied to all VPCs on all subnets. They are very broad and can become difficult to manage.
NSG
VPC. Network Security Group. Gives more granularity than a Network Security List. You can apply access control rules to a specific VNIC.
Private Cloud
Just within my organization. Apps or resources just in your org
Public Cloud
Azure - anyone who wants to join can. An app that you want other people outside of your org to access and use
Hybrid Cloud
Little bit of public and private - some of the cloud is segregated as private and other parts are public. Often times a large org with a lot of resources can sell out unused resources of their org