Protocol is a set of rules and restrictions that determine how data is transmitted over a network medium
Please do Not Throw Sausage Pizza Away
Application 7
Presentation 6
Session 5
Transport 4
Network 3
Data 2
Physical 1
encapsulation occurs as data moves down through OSI Model Layers from Application to Physical. It is the addition of a header and possibly a footer to the data received by each layer from the layer above before it is handed to the layer below
De-encapsulation occurs when data moves up through OSI model layers from Physical to Application
The presentation layer encapsulates the message by adding information to it, information is added at the beginning of the message i.e. a header.
D3SPFB
Application Data Stream
Presentation Data Stream
Session Data Stream
Transport Segment (TCP)/Datagram (UDP)
Network Packet
Data Frame (Link)
Physical Bits
accepts frame from the data link layer and converts frame into bits for transmission over the physical connection medium. It also receives bits from the physical connection medium and converts them into frame to be used by the data link layer.
Throughput rates
It handles synchronisation
Manages line noise and medium access
Determines whether to use analogue or digital signals
(NHRCA) Network Interface Cards (NICs), hubs, repeaters, concentrators and amplifiers.
Data Layer is responsible for formatting the packet from the Network layer into the proper format for transmission. data link layer includes adding the hardware source and destination addresses to the frame. The hardware address is the Media Access Control Address (MAC)
SPALLPI
Serial Line Internet Protocol (SLIP)
Point to Point Protocol (PPP)
Address Resolution Protocol (ARP)
Layer 2 Forwarding (L2F)
Layer 2 Tunnelling Protocol (L2TP)
Point to Point Tunnelling Protocol (PPTP)
Integrated Services Digital Network (ISDN)
Address Resolution Protocol (ARP) is a protocol the datalink Layer. It can be viewed as operating in layer 2 or 3 of the OSI model. It depends on the ethernet’s source and destination MAC addresses. ARP is used to resolve IP addresses into MAC addresses.
Payload, the Ethernet Frame
Tricky question! some think it operates on Layer 2,anyway choose 2. Layer 2
Layer 3 – Network layer but it does not operate as a true layer 3 protocol as it does not use a source destination addressing scheme to direct communications. It depends on the Ethernet source and the destination MAC addresses.
Ethernet (IEEE802.3), Token Ring (IEEE 802.5), Asynchronous Transfer Mode (ATM), Fibre Distributed Data Interface (FDDI), Copper Distributed Data Interface (CDDI)
Logical Link Control and Media Access Control (MAC) Sublayer
at datalink layer… switches and bridges
Network layer is responsible for adding routing and addressing information to data. Packet includes source and destination addresses. The Network layer is responsible for providing routing or delivery information, but it is not responsible for verifying guaranteed delivery
BORI5NS
Internet Control Message Protocol (ICMP)
Routing Information Protocol (RIP)
Open Shortest Path First (OSPF)
Border Gateway Protocol (BGP)
Internet Group Management Protocol (IGMP)
Internet Protocol (IP)
Internet Protocol Security (IPSec)
Internetwork Packet Exchange (IPX)
Network Address Translation (NAT)
Simple Key Management for Internet Protocols (SKIP)
routers determine the best logical paths for the transmission of packets based on speed, hops, preference and so on.
routers use destination IP addresses to guide the transmission of packets.
Routers and bridge routers (brouters)
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Bridge routers (brouters) works primarily in layer 3 but in layer 2 when necessary.
. Transport layer is responsible for managing the integrity of a connection and controlling the session. A PDU Payload Data Unit from the session layer is converted into segment. This layer includes mechanisms for segmentation, sequencing, error checking, controlling the flow of data, error correction, multiplexing and network service optimisation.