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Wall-plug to World. The UW campus network, from wall-plug to world … Roger Watt Director, Network Services Information Systems and Technology http://retirees.uwaterloo.ca/~rwwatt/. wall plug to campus, campus to world ….
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Wall-plug to World The UW campus network, from wall-plug to world … Roger Watt Director, Network Services Information Systems and Technology http://retirees.uwaterloo.ca/~rwwatt/
wall plug to campus, campus to world … • Connecting your computer to the campus network requires that your computer has a wired or wireless Ethernet interface and IP-network software … • technologies that form the transmission systems on campus, and the devices that interconnect them to create the campus IP network • UW's external connection to the Internet and the ORION (provincial) and CA*net4 (national) "research and education" networks
thickwire Ethernet (early 1980s) … Ethernet thickwire coax cable segment (max: 500m, 100 devices, min spacing 2.5m) transceiver transceiver cable (max: 45m) Attachment Unit Interface (AUI) port computer Ethernet board
thinwire Ethernet (mid 1980s) … BNC connector Ethernet thinwire coax cable segment (max: 185m, 29 devices, min spacing 0.9m) computer Ethernet board with BNC port and built-in transceiver
anything from any device on one cable segment is re-transmitted (repeated) onto the other cable segment connecting Ethernet segments with a repeater … local repeater c3 c4 c1 c2
re-transmits anything from a device on one cable segment that is destined for a device on the other segment (or is a "broadcast" destined for all devices) eliminating unnecessary traffic with a bridge … local bridge c3 c4 c1 c2
function is same as local repeater or local bridge, used for between-building links because fibre is electrically inert "remote" Ethernet repeaters and bridges ... fibre pair
multiport/multimedia repeaters ... multiport repeater everything received on one segment is repeated on all others
the Ethernet switch (mid 1990s) … a box full of N two-port bridges, all connected to a shared-access bus that is fast enough to allow N/2 concurrent transmissions; what is sent from one port is repeated only to the destination port
unshielded twisted pair (UTP) cabling … floor-area wiring closet: Ethernet switch UTP wiring panel four pairs of twisted 24g solid copper wires (max: 100m, 1 device) computer two-port faceplate in office Ethernet board with RJ45 port and built-in transceiver
the network as a critical university resource … • Managing the network … the early days … • 1990-04 DCS formed "Campus Network" group • 1990-05 AP-CIS formed "Campus Network Advisory Group" (CNAG) http://ist.uwaterloo.ca/CNAG/ • 1990-06 CNAG "Campus Network Management Plan" http://ist.uwaterloo.ca/cn/#Admin • 1990-Q4 search for technology to implement the Plan • 1991-01 DCS ordered hardware and software for "phase 1" • 1991-Q2 began restructuring the cabling-system topology • 1991-Q3 started developing "future fibre" plan
physical layer (fibre, copper, or radio) data-transmission layer (Ethernet) network layer (IP) IP ... the network-layer protocol by which computers communicate over different kinds of transmission-layer protocols and "cabling" media multiple IP networks are interconnected by IP routers the network layer …IP, the "Internet Protocol" ... { {
the IP protocol stack … A P S T N D P remote logon network mgmt file system web mail SMTP HTTP SSH etc CIFS SNMP 22 821 80 3020 161 TCP UDP 793 768 IP 791 DHCP ARP data-transmission protocols (Ethernet, Token Ring, FDDI, ATM, etc) wired and wireless media
protocol layers ... mail headers and body SMTP TCP header SMTP header IP packet TCP header Ethernet frame IP packet
The router achieves total isolation between the transmission systems of its connected networks. For c1 in network A to send an IP packet to c4 in network B, c1 must send the Ethernet frame containing the IP packet to the router’s Ethernet address in network A. The router examines the IP destination address, consults its table of routes, and transmits the IP packet from its Ethernet address in network B to c4's Ethernet address. IP routers connect multiple networks … cabling system for IP network C c1 c4 cabling system for IP network A cabling system for IP network B IP router
a first-level "management" backbone network that interconnects routers that interconnect dozens of 2nd-level networks containing the computing systems and lower-level workgroup networks within each of the major organizational units Campus-network layered architecture ... Campus backbone router1 router2 routerN
name.net IN A 129.97.subnet.0 IN HINFO "parent_subnet router" "IP" IN TXT "ORGUNIT unit,subunit,group" IN TXT "ADMINuserid" IN TXT "CONTACTuserid" IN TXT "LOCATION list of buildings" IN TXT "DATE yyyy-mm-dd" hostname IN A 129.97.subnet.xxx IN HINFO "vendor model" "opsys" IN TXT "ADMINuserid" IN TXT "CONTACTuserid" IN TXT "LOCATION bldg,room" IN TXT "DATE yyyy-mm-dd" subnet and host registration, DNS database …
Dynamic Host Control Protocol (DHCP) ... When you turn on your computer, it transmits a DHCP Ethernet broadcast packet containing its Ethernet address. Every device on the local cabling system looks at the DHCP packet, but only the device that handles DHCP requests (the DHCP "server") responds ... it sends back an Ethernet packet containing the IP address to be used, plus a "lease time" for which it is valid for your computer to be using that IP address. Your computer will re-issue a DHCP request before the lease expires. (If an IP address isn’t permanently assigned to your computer, there is no guarantee that you will get the same IP address back again.) How your computer learns its IP address …
Mapping from Ethernet to IP … Address Resolution Protocol ... • originating host generates an Ethernet broadcast packet that contains the IP number for which it wants the Ethernet address • every device on this local cabling system looks at it, but only the device with that IP number responds ... it sends an Ethernet ARP-response packet containing its IP number, addressed to the Ethernet address of the device that originated the ARP request • originating host caches that IP number in its ARP table for future use
Ethernet frames are transmitted via radio instead of copper or fibre. The AP is the DHCP server for the clients, and uses an "authentication server" elsewhere in the campus network to verify the identify of the person using the client computer. IEEE 802.11b=11Mbps(5), 11g&a=54Mbps(20) There are about 100 APs in the network today, and another 200 will be acquired to complete the provision of wireless access in all on-campus buildings. wireless access points (APs) ... ))))) wired-medium Ethernet transmission system ))))) c1 antenna ))))) AP c2
Connections to external communities of interest ... • The world-wide Internet is the vehicle by which the university conducts a great many aspects of its business ... • researchers communicate with colleagues on collaborative research, • staff communicate with suppliers and the staffs of other institutions, • students fulfill their academic obligations and develop skills to the advantage of their future employers, and • all have access to information far in excess of what the institution can afford to maintain locally (the world-wide digital library).
ORION …Ontario's gigabit-speeds R&E network http://ist.uwaterloo.ca/cn/ORION/
Parting words … • The next-generation network ... • Architected for resilience, security, QoS, multicast • 10Gbps Ethernet (and 100Gbps after that) • Wave Division Multiplexing … multiple Ethernets per fibre strand, each with its own frequency • Voice and TV are "just another IP application” • Wireless is the final frontier