1 1 OSI 7 Layer Basic PeertoPeer Communication

1. 1 OSI 7 Layer Basic Peer-to-Peer Communication Application Presentation Session Transport Router Transport Network Data Link Physical

1. 2 LAN Overview LAN 이란? 서버 LAN 터미널 : Local Area Network

1. 3 LAN Technology IEEE 802 LAN 표준 Application Presentation Session Transport Network Data Link LLC MAC Physical < OSI > < IEEE >

1. 3 LAN Technology IEEE 802 LAN 표준 Data Link L L C 10 Base 5 10 Base 2 10 Base. T 토큰 버스 1, 5, 10 Mbps IEEE 802. 5 CSMA /CD IEEE 802. 4 Physical IEEE 802. 3 M A C IEEE 802. 2 토큰링 4, 16 Mbps

1. 3 LAN Technology 10 Base 5 최대500 M MAU(Tranceiver) COAX(thick) AUI Cable (Tranceiver cable) 최소2. 5 M

1. 3 LAN Technology 10 Base. T HUB(REPEATER) 100 M UTP

1. 3 LAN Technology 10 Base. T UTP Cabling(EIA 568 B규격) PIN NO. 케이블 제작 실습 1 2 3 4 5 6 7 8 COLOR white/orange white/green blue white/blue green white/brown 기 능 TD+ TDRD+ RD-

1. 3 LAN Technology 고속 이더넷 Gigabit Etherner Media Options and Standards IEEE 802. 3 Z IEEE 802. 3 ab

1. 3 LAN Technology Ethernet Frame Ethernet frame(Ethernet _II) Preamble 8 bytes Destination 6 bytes Source 6 bytes Ethertype 2 bytes - FCS의 범위 : DA, SA, Ethertype, Data - DATA 길이 : 46 - 1500 옥텟 Data 46 - 1500 FCS 4 bytes

1. 3 LAN Technology 802. 3 Frame Preamble 7 bytes SFD Destination 6 bytes 1 byte Source 6 bytes Length 2 bytes Data FCS 46 -1500 4 bytes

1. 3 LAN Technology 802. 2 LLC Frame DSAP 1 byte SSAP 1 byte Control 1 -2 bytes Network layer data

1. 3 LAN Technology SNAP Frame DSAP SSAP Control 1 byte OUI Ethertype Network layer data 3 byte 2 byte SNAP header (5 byte) -DSAP, SSAP : 0 x. AA - Control : 0 x 03 - OUI (Organizational Unit Identifier) : TCP/IP 일 경우 0

1. 3 LAN Technology 각 Frame에 대한 비교 Preamble Destination Source Ethertype Data 8 bytes 6 bytes 2 bytes 46 - 1500 Ethernet Frame FCS 4 Destination Source Length 802. 2헤더와 FCS 6 bytes 2 bytes 46 -1500 4 IEEE 802. 3 + LLC 802. 2 Frame Preamble SFD 7 bytes 1 DSAP SSAP Control 1 byte 1 -2 bytes Network layer data LLC 802. 2 Frame

1. 4 Internetworking Technology Bridging LAN 1 A 3 3 LAN 2 LAN 3 1 브리지1 2 1 브리지2 2 B

1. 4 Internetworking Technology Switching Shared High Speed Line Bridge Dedicated Line Internal Architecture • Multi-port Bridge Switch

1. 4 Internetworking Technology Redundant Topology Server/host X Router Y Segment 1 Segment 2 q Redundant topology eliminates single points of failure q Redundant topology causes broadcast storms, multiple frame copies, and MAC address table instability problems

1. 4 Internetworking Technology Broadcast Storm Server/host X Router Y Segment 1 Switch A Broadcast Switch B Segment 2 q Switches continue to propagate broadcast traffic over and over

1. 4 Internetworking Technology Spanning Tree Protocol 100 base. T Designated port (F) Root bridge Nonroot bridge SW X SW Y Designated port (F) Nondesignated port (B) x 10 base. T q One root bridge per network q One root port per nonroot bridge q One designated port per segment

1. 4 Internetworking Technology Root Bridge 결정 Switch X Default priority 32768 (8000 hex) MAC 0 c 001111 BPDU Switch Y Default priority 32768 (8000 hex) MAC 0 c 002222 BPDU = Bridge protocol data unit Root bridge = Bridge with the lowest bridge ID Bridge ID = Bridge priority + bridge MAC address

1. 4 Internetworking Technology Spanning Tree Port States Spanning-tree transitions each port through several different state: Blocking Listening Learning Forwarding

1. 4 Internetworking Technology VLAN • Segmentation 3 rd floor • Flexibility 2 nd floor 1 st floor • Security SALES HR ENG 1 VLAN = 1 broadcast domain = Logical network (subnet)

1. 4 Internetworking Technology VLAN 동작 Switch B Switch A Trunk Fast Ethernet Red VLAN Black VLAN Green VLAN q Each logical VLAN is like a separate physical bridge q VLANs can span across multiple switches q Trunks carries traffic for multiple VLANs

1. 4 Internetworking Technology VLAN Tagging ISL trunks enable VLANs across a backbone VLAN Tag added by incoming port VLAN Tag stripped by forwarding port § Performed with ASIC Inter-Switch Link carries VLAN identifier § Not intrusive to client stations, client does not see the ISL header § Effective between switches, routers and switches, switches and servers with ISL network interface cards

1. 5 WAN Overview WAN이란? q WANs connect remote sites. q Connection requirements vary depending on user requirements, cost, and availability.

1. 6 WAN Technology WAN connections

1. 6 WAN Technology WAN Protocols HDLC PPP X. 25 Frame Relay. . .

1. 6 WAN Technology HDLC frame format • Uses a proprietary data field to support multiprotocol environments • Supports only single-protocol environments

1. 6 WAN Technology PPP Overview • PPP can carry packets from several protocol suites using NCP. • PPP controls the setup of several link options using LCP.

1. 6 WAN Technology Layering PPP elements • PPP: A data link with network layer services

1. 6 WAN Technology PPP session establishment • Two PPP authentication protocols: PAP and CHAP

1. 6 WAN Technology Frame Relay Topology • Frame Relay default: nonbroadcast, multiaccess (NBMA)

1. 6 WAN Technology Frame Relay 일반

1. 6 WAN Technology Frame Relay Address mapping – Use LMI to get locally significant DLCI from the Frame Relay switch. – Use Inverse ARP to map the local DLCI to the remote router’s network layer address.