Week 4 - The Network Layer Flashcards
What Two Functions Does The Logical Link Control Perform?
- Handles Communication Between The Upper And Lower Layers And Fills In The Networking Protocol (Sending)/Passes It On To The Correct Networking Protocol (Receiving)
- Takes The Network Protocol Data And Adds Control Information To Help Deliver The Packet To The Destination (Flow Control And Reliability Of Connection!).
- What Networking Hardware Implements The MAC Layer 2 Sublayer?
- What Are The Two Responsibilities Of The MAC Sublayer?
- The Network Interface Card (NIC)
- Data Encapsulation (Packet To Frame).
- Media Access Control (Allowing It Onto The
Transmission Media)
The MAC Layer Encapsulates Data Further From A Packet. What Is Added By The MAC Sublayer Upon A Packets Encapsulation Into A Frame.
A Header (Containing The Start Flag And The Data) And A Trailer (Containing The FCS (Frame Check Sequence) For The Cyclic Redundancy Check Are Added.
What Are The Two Primary Responsibilities Of The MAC Sublayer?
- Data Encapsulation (Frame Packets)
- Media Access Control (Interacting With The Physical Layer Processot (PYH) To Get The Frame Onto The Media.
In The MAC Sublayer, What Is Frame Delimiting?
Adding Groups Of Bits (Flags) To Indicate The Start And End Of A Frame.
In The MAC Sublayer, What Is Addressing?
Adding A MAC Address To Deliver To A Destination Node.
In The MAC Sublayer, What Is Error Dectection?
Using The Cyclic Redundancy Check To Perform A Polynomial Division And Verify The Integrity Of The Frame.
Each NIC Views Each Recieved Frame To See If The …………………………. in the frame matches the devices’s ……………………………. stored in RAM.
Each NIC Views Each Recieved Frame To See If The Destination MAC Address in the frame matches the devices’s Physical MAC Address stored in RAM.
If A Frame’s Destination MAC Address Does Not Match The MAC Address Of The Device Recieving The Frame, The Frame Is…….
Dropped.
If The MAC Address Of The Incoming Frame Matches The MAC Address Of The Receiving Device……….
The NIC Passes The Frame Up The OSI Layers Where It Is Decapsulated And Passed Back To The Application.
What is The:
- Minimum Possible Size A Frame Can Be (In Bytes)?
- Maxiumum Possible Size A Frame Can Be (In Bytes)?
- 64 Bytes
2. 1518 Bytes (Jumbo Frame)
How Many Bits Make Up A MAC Address?
48 Bits
What Is The OUI Section Of A MAC Address. How Many Bytes Does It Occupy?
- The Organizationally Unique Identifier, It Identifies The Manufacturer Of The Device! It Occupies The First 3 Bytes Of A MAC Address.
What Do The Last Three Bytes Of A MAC Address Represent? In Theory, What Should Property Should This Address Have?
- The Vendor Assigned Address. These Bytes Should Be Globally Unique! (No Other Device Should Share It!!!)
What Fields Are Used To Direct A Packet To It’s Destination?
The Destination MAC and IP Addresses.
What Are The First Three Bytes Used By A Frame’s Destination MAC When A Multicast Transmission Is Made?
01-00-5E
What Range Of IP Addresses Are Used To Identify A Multicast Transmission?
224.0.0.0 to 239.255.255.255
(MAC Address Is Mapped Onto The Multicast IP - Hosts Then Join The Group And ‘Listen’ For Broadcasts Made To The Group.
A MAC Address Does Not………. And Is Known As A ……………………. Address
A MAC Address Does Not Change And Is Known As A Physical Address
An IP Address Is Based On Where The Host…………………………………………… And Is Known As A ………………………… Address.
An IP Address Is Based On Where The Host Is Actually Located And Is Known As A Logical Address.
A Switch Examines…………………….
MAC Addresses
A Router Examines……………………
IP Addresses.
What Does ARP (Address Resoluton Protocol) Allow Nodes To Discover?
The MAC Address OF A Device Connected To A LAN
ARP Protocol Allows:
- The ……………………………. of IPv4 Addresses To ……………………………………….
- Devices To Maintain A Table Of……………………………….
The Resolution of IPv4 Addresses To MAC Addresses.
Devices TO Maintain A Table Of Mappings
What Does The ARP Table Do?
When A Node Recieves A Frame From The Media, It Records Which IP It Came From And Associates It With The MAC Address The Frame Was Sourced From.
What Is An ARP Request?
A Layer 2 Device Broadcasts To All Devices With The Destination IP Address Of An Incoming Frame. If A Device Matches The IP Address, It Responds. The Router Then Updates The IP Stored In It’s ARP Table With The MAC Address Of The Responding Device.
What Will The Destination MAC Address Of A Frame Be When Sent To A Device On The Same Network?
- The MAC Address Of The Recipient Host Device.
- What Will The Destination MAC Address Of A Frame Be When Sent To A Device That Is Not On The Same Network?
2.
- The MAC Address Of The Routing Interface Assigned As The Default Gateway.
