IST 228Ch 1Internetworking CollisionBroadcast Domain The term collision

IST 228Ch 1Internetworking Collision/Broadcast Domain • The term collision domain defines the set of devices for which their frames could collide • A broadcast domain is a set of NICs for which a broadcast frame sent by one NIC will be received by all other NICs in the broadcast domain. • Hub? • Bridge? • Switches? • Routers? 1

IST 228Ch 1Internetworking Identify collision and broadcast domains for each case 2

IST 228Ch 1Internetworking 10 -Mbps Ethernet • No hub, switch, or wiring panel. The series of cables creates an electrical bus • the carrier sense multiple access collision detect (CSMA/CD) • 10 Base 2: 10 Mbps, baseband technology, almost 200 meters • 10 Base 5: 10 Mbps, baseband technology, almost 5 00 meters 3

IST 228Ch 1Internetworking Ethernet Networking with a Hub Half-Duplex 10 Base. T 1. The network interface card (NIC) sends a frame. 2. The NIC loops the sent frame onto its receive pair. 3. The hub receives the frame. 4. The hub sends the frame across an internal bus so that all other NICs can receive the electrical signal. 5. The hub repeats the signal to each receive pair to all other devices. 4

IST 228Ch 1Internetworking Ethernet Networking with a Switch Full Duplex Ethernet • Full-duplex means that an Ethernet card can send and receive concurrently. • Use a switch or direct connection from host to using a crossover cable. • The switch interprets the electrical signal as an Ethernet frame and processes the frame to make a decision. • Hub – Layer 1 • Switch – Layer 2 5

IST 228Ch 1Internetworking 6 Basic Ethernet Features 10 Base 2, 10 Base 5 Single bus cabled serially between devices using coaxial cable. 10 Base. T with a Hub One electrical bus shared among all devices creating a single collision domain, cabled in a star topology using twisted-pair cabling 10 Base. T with a Switch One electrical bus per switch port creating multiple collision domains, cabled in a star topology using twisted-pair cabling Half Duplex Logic that requires a card to only send or receive at a single point in time. Used to avoid collisions Full Duplex Logic that enables concurrent sending and receiving, allowed when one device is attached to a switch port, ensuring that no collisions can occur.

IST 228Ch 1Internetworking Ethernet Addressing • Ethernet uses MAC address burned into each NIC. • 48 bits (6 bytes) • First 3 bytes assigned by IEEE • Unicast MAC Address • Broadcast MAC Address (FFFF) • Multicast Address 7

IST 228Ch 1Internetworking Ethernet Frames • Framing defines how a string of binary numbers is interpreted • • Preamble SD: Start frame eliminator Destination MAC address – Unicast – Broadcast – Multicast Source address Length of file DSAP SSAP, SNAP (Subnet Network Access Protocol) Control/Data Frame Check Sequence (FCS) 8

IST 228Ch 1Internetworking 9 Ethernet Cabling Straight-Through Cable • Host to Switch or hub • Router to Switch or hub Rolled Cable • Serial Port Crossover Cable • Switch to Switch • Hub to Hub • Host to Host

IST 228Ch 1Internetworking 10 Data Encapsulation &@$ Hello! • Step 1: Data Conversion Application hello Presentation PDU 1 101010011100100 PDU 2 PDU 1 101010011100100 Session PDU 3 PDU 2 PDU 1 101010011100100 Name: Data Stream • Step 2: Data segmentation Transport TCP PDU 3 PDU 2 PDU 1 0101010 TCP PDU 3 PDU 2 PDU 1 0100100 : : Name: Segment

IST 228Ch 1Internetworking 11 • Step 3: Packet creation for routing Network IP TCP PDU 3 PDU 2 PDU 1 0101010 IP TCP PDU 3 PDU 2 PDU 1 0100100 : : Name: Packet or Datagram • Step 4: Frame Header Data Link LLC 802. 2 MAC 802. 3 MAC LLC IP TCP PDU 3 PDU 2 PDU 1 0101010 Name: Frame • Step 5: Transmission Physical 10010100001 Layer FCS

IST 228Ch 1Internetworking LAN Design Models • Mesh design • Hierarchical design – Three-layer network model – Two-layer network model – One-layer network model 12

IST 228Ch 1Internetworking Three Layer Model • Core-layer • Distribution Layer – a backbone network connecting all LANs – no end user at this level – implementation of security and network policies • Access Layer 13

IST 228Ch 1Internetworking Two and One-Layer Model 14