Network Implementation (Chapter 2) Flashcards
Routing
Is the movement of packets between network based on Layer 3 headers, performed by routers. They pass the packet along (hop) until the packet reaches it’s destination.
Router golden rule
All routers must know what to do with packets, either by having the packets destination in it’s routing table or by having a default route to pass the packet to
Default Route
Is route that a router sends packets to when there are no other available routes
2nd Golden Rule of Routing
The router must be able to choose which interface to send the packet out of. Each router interface must belong to a different network
Static Routing
Is when routes are manually entered into the routing table. All route must be entered into all routing tables or packets will be lost. It allows a router to know which route to take to reach a network
Dynamic Routing
Routers use protocol that are used to inform routers of routes upstream.
Routing Protocols
Distance Vector
- routers on fixed intervals would broadcast their route tables which would be used by other routes to update their route tables
Link State
- would only broadcast route table updates when a link changes state
- Routing Information Protocol (RIP)
Hybrid
- uses the best of both link State and distance Vector
- Enhanced Interior Gateway Routing Protocol (EIGRP)
Path Vector
- determines the best path by maintaining route path information and policies
- Border Gateway Protocol (BGP)
Interior/Exterior Gateway Protocols
Interior Gateway Protocols
- are protocols used within a private network
- RIP, OSPF, EIGRP, iBGP
Exterior Gateway Protocols
- used between ISP on the internet
- BGP
Border Gateway Protocol
Is an exterior router protocol that allows a router to count an autonomous system as a single hop
- Exterior
- TCP 179
- unicast
- slow convergence
- administrative distance 20
- no load balancing
- complex to set up
Enhanced Interior Gateway Routing Protocol (EIGRP)
Is a protocol used by routers that ensures that each router on an interior networks maintains a topology table of the entire network
- interior
- Protocol ID 88
- administrative distance 90
- has loads balancing
- easy to set up
Autonomous System
An Identifiable number assigned to a network that is under a single administrative that controls 50000 routes within their network
EIGRG Successor/Feasible Successor
Successor
- is the best route to a destination
Feasible Successor
- is a backup route to the same destination
OSPF
Is a protocol for routers that divides a network into areas into a Hierarchical structure.
- Interior
- Protocol ID 89
- multicast
- fast convergence
- administrative distance 110
- No load balancing
- complex to setup
Router forwarding decisions
Routers make routing decision based on
- longest prefix match (route with the longest CIDR mask)
- administrative distance
- Routing Protocol Metric
Prefix Length
Prefix is the length of the subnet mask in the router (largest CIDR number).
A longer prefix is more specific to where the destination is.
Prefix Length
First criteria for route selection
Prefix is the length of the subnet mask in the router (largest CIDR number).
A longer prefix is more specific to where the destination is.
Administrative Distance
2 criteria for route selection
Is the believability of a route source which could be Directly connected, statically entered or a routing protocol. Each source has an administrative distance.
Routing Protocols Metric
Third criteria for route selection
Is the cost of a particular route compared with other routes with the same adminstrative distance
Network Address Translation
Performed by routers and firewalls that translates the internal private IP address into a public IP address to access the internet.
- Packets IP are temporarily changed to the public IP
Port Address Translation
Performed by routers when multiple devices are attempting to access the internet, it translates their private IP address into the same Public IP address but the router maintains the devices original source port.
First Hop Redundancy Protocol (FHRP)
Is when multiple routers act as a single default gateway for all host on a network.
- all routers will share a Virtual IP and Virtual MAC that all host will send their traffic to
Subinterfaces
Are logical interface created on a routers physical interface that allows multiple VLAN to use the logical interface as it’s default Gateway and subnet
Maximum Transmission Unit (MTU)
The maximum size (bytes) a frame can be on a network segment.
- default size for ethernet frames: 1500 bytes
Jumbo Frame
Allows for ethernet frames to be larger than the default ethernet MTU, upto 9000 bytes.
Used to increase performance and reduce the number of frames needed for large data transfers
Virtual Local Area Network (VLAN)
Is a logical grouping of physical ports on a switch. It groups ports into multiple separate networks.
- created on access Layer switch and can be extended over other switches via a trunk link
VLAN Database
- Old switches store their VLAN information in a vlan.bat file
- newer switches maintain VLAN information in the switch configuration file
Default VLAN
Is the VLAN that all switch ports are initially assigned to
- VLAN 1
Voice VLAN
Is the ability of a switch to create and additional VLAN on a port that already has a VLAN to support Voice. The switch will be connected to the phone and the phone will be connected to the PC
Uplink
Is a connection between switches in which an Ethernet cable is connected via their ports. It’s used to add more devices into a switch port (VLAN)
Trunk Link
Is an uplink connection in which both switch ports have been configured to carry traffic for all VLAN from one switch to the next. They are used to extend multiple VLANs across multiple switches
VLAN Trunking
The process of extending VLANs over multiple switches.
- a single VLAN can be spread out across multiple switches
Protocol: 802.1Q
VLAN Tagging
Are VLAN ID number that are encoded into an Ethernet frames header that is used to distinguish which VLAN that frame belongs to.
- The VLAN ID is encoded by the sending trunk port allowing the recieving switch to forward the frame to the appropriate VLAN.
- Default VLAN 1 frames are sent across without any tagged
Native VLAN
Is the default VLAN that a trunk port will revert to if the trunk port configuration has been changed to a normal access port
Native VLAN Mismatch
Is when the native VLAN (default VLAN) on multiple switches are not configured to the same VLAN
InterVLAN Connectivity
By default VLAN are unable to communicate with eachother, they are each on separate subnet. For VLANs to communicate to eachother they need to be routed, thus the traffic needs to go through router (layer 3).
- Router can have a physical connection to each VLAN
- Router-on-Stick (a router interface that has a trunk port to the switch)
- VLAN Interface (uses a multilayer switch that has a built in router)
Router-on-Stick
Is a trunk link between a switch and a router that allows the router to create a logical subinterfaces for all the VLANs that the switch is connected to. Thus allowing the router to route the VLAN traffic to the other VLANs.
Switch Virtual Interface (SVI)
Is a logical layer 3 interface created on a multilayer switch, with routing capabilities, that acts as a default gateway for a VLAN, this allows VLANs to use their logical interface as a default gateway to route across to other VLANs
Link Aggregation
Is the bundling if multiple physical ethernet links into a single logical link (channel), the channel provides bandwidth, redundancy and load balancing.
Protocols:
- Port Aggregation Protocol (PAgP)
- Link Aggregation Control Protocol (LACP)
Switching Loop
Is an issue that occurs when there are redundant links between switches and a broadcast, multicast, or unknown unicast is forwarded to all ports which will cause that packet to be sent back and forth between the switches and all it’s port creating a loop.
Spanning Tree Protocol (STP)
Prevents switching loops by enabling port blocking. It ensuring that there is only one active path between networks. If there is a redundant patch between network then the less desirable path will be temporarily blocked.
Wireless LAN Controller (WLC)
Is a centralizes controller used to configure and managed specialized Wireless Access points, as well as connecting the WAP the to rest of the network
802.11h
A new WiFi protocol that introduces Dynamic Frequency selections (DFS) and transmit power control (TPC)
Dynamic Frequency Selections
- will switch between channels if one channel experience high frequency
Transmit Power Control
- reduces the power consumption of access points this reducing the RF it gives off
Band steering
Is a technology if a WAP that attempts to connect devices to the best availability WiFi frequency
Ad Hoc
Is a wireless network type that is connected peer-to-peer without having to connected to a an access point
Infrastructure network
Is a network type in which all devices are connected to a centralised access point
Mesh WiFi network
Is a network type that interconnects multiple access points allowing them to communicate with eachother forming a mesh topology.
mesh component:
- Root Access Point
– is an access point that is connected to the rest of the network
- Meash Access Point
– all other access points that communicate to one another
-backhaul
– the connection between all the Access points
Backhaul
Is a connection between multiple access points that uses a less used frequency to communicate with one another
Guest wifi
Guest are able to connected to the WiFi via a separate VLAN isolating guest from the rest of the network
Captive portal
A convenient authentication mechanism for temporary WiFi access to an organisation’s network, allow management manage guest on network
Pre-shared Key (PSK)
The WiFi password used to access the network, aka WiFi password
WiFi Antenna
Is a critical component of a wireless network that allows the access point to radiat radio signals to devices
Omnidirectional Antenna
- radiates signals in all directions
Directional Antenna
- focus signals in on direction for long range or higher signal quality
Omnidirectional Antenna Patterns
High Gain OMNI
- has a radiation pattern similar to a flatter bagel
- allows signals to travel further horizontally
Lower Gain OMNI
- has a radiation pattern similar to a fat donut
- allows signals to travel further vertical
