N10-009-Section_2 Flashcards
Static Route
A static route is a fixed route that is manually configured and persistent. Can use less CPU/Memory resources cause there is no math being done to generate the routing table. Can also be more secure cause there are no routing protocols to analyze. Can be difficult to manage on larger networks.
Routers�
Filter and forward based on IP addresses. Interconnect network IDs. Routers don�t care where a packet came from, just where its going. Routers arent tied to Ethernet, they can have Dosis, Optical, all sorts of other connections
Routing Table
Table of info of connected network IDs and how to get to them
Default Route
If your router doesn�t know where to route data, it will send it up to its upstream router
Upstream Router
ISP’s router is called the upstream router
Metric (Routing)
Value that gives your router a route priority when there are equal options. Example: you have 2 uplinks from different ISPs, how does your router know which one will be the primary default route
Dynamic Routing
When routers automatically send routing tables to each other and converge on the best routs to different places
What is OSPF?
The main IGP - Open Shortest Path First - Uses Link State Protocols - Requires a single router to be the boss router (Elected Automatically, also elects a backup boss router). Uses Area IDs to designate the territory of each router (Area IDs are not IP address, although they look similar) OSPF can get to convergence faster than RIP. OSPF will choose the fastest link with the lowest cost. (For cost, see Link-State)
What is BGP?
Border Gateway Protocol - Hybrid protocol, has aspects of Distance Vector and Link State - Cornerstone of the Internet as it’s how ISPs talk with each other - BPG breaks the internet into ASes and routes data between them using the AS number.
EIGRP
EIGRP (Enhanced Interior Gateway Routing Protocol) is a dynamic routing protocol developed by Cisco, designed for use in IP networks to find the best path for data transmission. EIGRP is a hybrid routing protocol, combining aspects of both link-state and distance-vector protocols, and it is considered an advanced version of the older IGRP (Interior Gateway Routing Protocol).
What are the 2 kinds of routing methods Dynamic Routing Protocols use?
Distance Vector and Link State
What is Distance Vector?
One of the main types of Dynamic Routing Protocols Routing Methods, the grandfather. Where a router will send its entire routing table to all its neighbors for Convergence. Issues: Relies on hop count, sends routing table/info on an interval, so if something changes, it won’t update everyone else instantly. Example is RIP
What is Link State?
One of the main types of Dynamic Routing Protocols Routing Methods, the more modern one. Link state routers will check in with its neighboring routers every once in a while to see if anything has changed, it will also send updates as it detects changes (advertising). Example is OSPF. Each link has a “cost” that is based on the amount of throughput, reliability and round trip time and paths are chosen with this cost in mind.
What are the 2 kinds of routing scopes Dynamic Routing Protocols use?
IGP (Interior Gateway Protocols) and EGP (Exterior Gateway Protocols) - Protocols used to determine the most efficient path for data to travel between networks - This is a category of routing protocols, not a protocol itself
What is IGP?
IGP (Interior Gateway Protocol) - Used within a single AS - IGP Protocols can be Distance Vector or Link State - RIP, OSPF, EIGRP
What is EGP?
EGP (Exterior Gateway Protocol) - Used between different ASes - There is only 1 EGP and that is BGP (Border Gateway Protocol) Used by ISPs to talk with other ISPs
What is an AS?
Autonomous System - One organization that has control of their own routers - an ISP or a University
What is an ASN?
Autonomous System Number - Every AS is assigned a number (32-bit number) - this number is used in BGP to route information back and forth
What is RIP?
Routing Information Protocol - RIP is an IGP and a Distance Vector Protocol - RIP is where routers will exchange routing tables with each other to discover paths to other networks. RIP will use the hop count to determine the metric for each route. Max hops is 15. RIP can be slow cause there is a fixed interval for when it will exchange routing tables. RIP 2.0 can handle CIDR and has increased security
Convergence
Where all routing tables reflect all routes
Prefix Lenths in Routing
The most specific entry in the routing table “wins” as the best route. So the destination 192.168.1.6 is contained within the table entry of 192.168.0.0/16, but the entry 192.168.1.6/32 is more specific so that will be the entry chosen as the route. The higher the prefix (CIDR) the more specific the route.
Administrative Distances
What if you have two routing protocols and both know about a route to a subnet? Each routing protocol has a different metric calculation and you can’t compare metrics across routing protocols. Which one is do you trust the most? Each routing protocol within a router has an administrative distance and that determines which protocol has priority.
FHRP
FHRP stands for First Hop Redundancy Protocol. It’s a family of protocols used in networking to provide redundancy and high availability for the default gateway in a local network. FHRP ensures that if one gateway (usually a router) fails, another can take over immediately, minimizing downtime for connected devices. The backup router will detect that the main router is no longer online and will elect itself as the active router and take over the VIP.
Subinterfaces
Subinterfaces are virtual interfaces created on a physical network interface card (NIC) or port on network devices like routers or layer 3 switches. These subinterfaces allow a single physical interface to handle traffic for multiple VLANs (Virtual Local Area Networks) or different network segments, enabling inter-VLAN routing, IP address segmentation, and more efficient network management.
NAT Overload / PAT
PAT (Port Address Translation) is a form of Network Address Translation (NAT) that allows multiple devices on a private network to share a single public IP address when accessing external resources, such as the internet. PAT works by using different port numbers to distinguish between the different connections from devices on the internal network.
Trunking
A trunk port moves all VLAN traffic across switches. This is done by tagging the port
802.1Q
802.1Q is an IEEE standard that defines VLAN tagging for Ethernet frames, allowing multiple virtual LANs (VLANs) to coexist on a single physical network. It is commonly used in network switches to manage traffic across different segments of a network, isolating broadcast traffic and improving network security and efficiency.
Native vs Default VLAN
Default VLAN is the VLAN assigned to an interface by default, usually VLAN 1. a Native VLAN doesn�t add an 802.1Q header, can traverse a trunk.
Layer 3 Switch
A switch that is able to make forwarding decisions based on IP address, like a router. This kind of switch can route between VLANs.
SVI
An SVI (Switched Virtual Interface) is a logical interface on a layer 3 switch or router that allows the device to perform IP routing within a VLAN (Virtual Local Area Network). SVIs are typically used to enable communication between devices in different VLANs and allow a switch or router to act as the default gateway for devices within a VLAN.
LAG
Link Aggregation / Port Bonding. Multiple interfaces acting as one large interface. Usually used to increase throughput.
LACP
LACP (Link Aggregation Control Protocol) is a protocol used to combine multiple physical network links into a single logical link, known as a Link Aggregation Group (LAG), to increase bandwidth and provide redundancy. LACP is part of the IEEE 802.3ad standard and is commonly used in Ethernet networks.
MTU
Maximum Transmission Unit - Ethernet is 1500 bytes - but not all protocols are limited to this
Jumbo Frames
Jumbo Frames are Ethernet frames that are larger than the standard maximum transmission unit (MTU) size of 1500 bytes. The standard Ethernet frame size is typically up to 1500 bytes, but jumbo frames allow for much larger payloads, typically in the range of 9000 bytes to 9216 bytes, depending on the network equipment and configuration.
802.1D / STP
Spanning Tree Protocol. A technology to prevent layer 2 loops. STP port states can be Blocking=not forwarding to prevent a loop, Listening=not forwarding and cleaning the MAC table, Learning=not forwarding and adding to the MAC table, Forwarding=data passes through normally, Disabled=admin has turned off the port.
Root Port
An STP port that leads back to the root bridge/switch
802.1w / RSTP
Rapid STP. Latest standard of STP. Faster convergence, old STP might take 30-50 seconds. On RSTP it could take only 6 seconds. RSTP is backwards compatible with STP.
Band Steering
Band Steering is a feature used in wireless networks, particularly in dual-band Wi-Fi routers or access points (APs), to optimize the connection experience by automatically directing client devices to the most appropriate Wi-Fi frequency band (typically 2.4 GHz or 5 GHz). The goal of band steering is to improve network performance by balancing the load between the two bands, minimizing congestion, and improving overall throughput and reliability.
802.11h
802.11h is an extension to the IEEE 802.11 Wi-Fi standard, specifically designed to improve the operation of wireless networks in regions where Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) are required. It was introduced to comply with regulatory requirements for 5 GHz Wi-Fi operation, especially in Europe, where Wi-Fi networks must avoid interfering with radar systems (such as weather radar or military radar) operating in the same frequency range.
DFS
In wireless networking, DFS stands for Dynamic Frequency Selection. It is a mechanism used in Wi-Fi networks operating in the 5 GHz band to minimize interference with other systems, particularly radar systems that share the same frequency range.
TPC
In wireless networking, TPC stands for Transmit Power Control. It is a mechanism used to regulate the transmission power of a wireless device to optimize performance and reduce interference.
6GHz
GHz (Gigahertz) is a unit of frequency that represents billions of cycles per second. It is commonly used to measure the frequency of electromagnetic waves, including radio waves, and is especially relevant in fields like telecommunications, networking, and computing.
WPA2
WPA2 (Wi-Fi Protected Access 2) is the successor to WPA (Wi-Fi Protected Access) and was introduced in 2004 as part of the IEEE 802.11i standard. Utilizes CCMP Block Cipher mode which combines encryption with AES and CBC-MAC for its MIC (Message Integrity Check)
WPA3
WPA3 (Wi-Fi Protected Access 3) is the successor to WPA2, Utilizes GCMP Block Cipher mode (Galois/Counter Mode Protocol). Still uses AES for encryption but uses GMAC (Galois Message Authentication Code) for MIC (Message Integrity Check)
Ad hoc / IBSS
Ad Hoc Mode is a wireless network configuration where devices communicate directly with each other without the need for a central access point (AP). In Ad Hoc mode, devices establish a peer-to-peer network, allowing them to exchange data directly. Also called Independent Basic Service Set
SSID
Service Set ID
BSSID
Basic Service Set ID - the hardware address of an Access Point
ESSID
Extended Service Set ID - Multiple WAPs working together with the same SSID
Captive Portals (Wireless Security)
Captive Portals are a method used in network management to provide guest access to a wireless or wired network, often with the requirement for user authentication before accessing the internet or internal resources. They are commonly used in public spaces (like coffee shops, airports, hotels, etc.) or in enterprise networks to control and secure guest access.
WEP
Wired Equivalent Privacy - used 64 and 128 bit keys - crackable, old
802.11i (WiFi Security)
802.11 committee’s first answer to problems of WEP - took too long to come out
WPA
WiFi Protected Access - Created cause 802.11i was taking too long. Uses TKIP
TKIP
TKIP (Temporal Key Integrity Protocol) is a security protocol used to provide data integrity and encryption for wireless networks, particularly those based on the IEEE 802.11 standard (Wi-Fi). TKIP was designed as a replacement for WEP (Wired Equivalent Privacy), which had significant security vulnerabilities. It was introduced as part of WPA (Wi-Fi Protected Access) to enhance the security of wireless communication.
AES
AES (Advanced Encryption Standard) is a symmetric encryption algorithm widely used to secure data. It replaced the older DES (Data Encryption Standard) due to its stronger security and efficiency. AES is the encryption standard endorsed by the U.S. government and is used globally in various applications, including securing communications, financial transactions, and data storage.
Omni Antenna
Send out radiation pattern in the shape of a sphere
Dipole Antenna
Two antennas that go opposite of each other - donut shaped pattern, goes out wide but not up and down
Patch Antenna
Half of a sphere - mounted to a wall, but wont shoot through the wall
Directional/Yagi Antenna
Stretched football shape, high gain, looks like a tree pointed in a direction
Directional/Parabolic
Another directional antenna - used for outdoors to shoot a signal a long way, kind of dish with a pole in the middle
SMA Connector
SubMiniature Version A - Antenna connector
Normal Gain for 100-200’ - dipoles and patches
3-5 dBi
Normal Gain for directional antennas
20-30 dBi
Autonomous vs. Lightweight Access Points
In the context of wireless networking, Autonomous Access Points (APs) and Lightweight Access Points (APs) - Autonomous Aps don�t need additional software or hardware to work, this is like the Aps in your house. Lightweight, most of the intelligence is in the switch that would need to be attached. Lightweight APs are less expensive
Infrastructure Mode
Infrastructure Mode is a wireless network configuration where wireless devices (clients) communicate through an access point (AP) rather than directly with each other. It is the most common setup for Wi-Fi networks, especially in enterprise and home environments, and is used to connect devices like laptops, smartphones, and tablets to a network.
MDF
Main Distribution Frame. The Central point of the network. The room or area where all the runs are terminated/punchdown.
IDF
Intermediate Distribution Frame. A secondary Distribution Frame that is connected to the MDF.
Offline/Standby UPS
The APCs we use, least expensive, waits for power to go out, then it kicks in, there is a small gap when there is no power before the battery starts up
Line-Interactive UPS
Can regulate the amount of power and increase the throughput to smoothen out brownouts
On-line/Double-Conversion UPS
Always running on the battery power, and the batteries are always charging
PDU
Power distribution units. Sorta like the ADJ switches we use, but smarter, the interfaces can be managed via ethernet
Recommended Humidity for Datacenters and network equipment
40%-60%. Too much humidity can cause condensation, but too little can cause static discharge
Optimal temp for Datacenters and network equipment
64 to 81 degrees F (17.7-27.2 C)
