Terminology and basic structures for lab 1 ©2012 Prof. José María Foces Morán

 LAN : Local Area Network. 10 to 1000 m  University campus.  MAN : Metropolitan Area Network. 1 a 10 Km  A city  WAN : Wide Area Network. Más de 10 Km  A province, a country ©2010 Prof. José María Foces Morán

 Medios físicos de transmisión  Twisted pair cables  Inexpensive, entre 10 y 1000 Mbps (Mega bits per second) ▪ STP (Shielded Twisted Pair) ▪ UTP (Unshielded) ▪ Cat 3 (30 Mbps) ▪ Cat 5 (100 Mbps) ▪ Cat 6 (1 Gbps) ©2010 Prof. José María Foces Morán

 Coaxial cables  Single, inner conductor ▪ Thick (2Km max length, 20Mbps max. frequency) ▪ Thin (RG-58/U)  Noise sensitive  T Connector, BNC type  Termination resistors ©2010 Prof. José María Foces Morán

 Fiber optics  Transmission of light ray in a light- transmitting material  Immune to electromagnetic radiation  In the order of Gbps, depending on grade  Monomode  Multimode  Laser and LED drivers ©2010 Prof. José María Foces Morán

 Network Interface Card (NIC)  Provides access to a LAN  By using a cable or optical fibers  Connected to a computer by using a PCI-X bus  Associated to a unique level-2 address ▪ MAC (Media Access Control address) o LLA ( Link Level Address ) ▪ A 48-bit number assigned by the IEEE ©2010 Prof. José María Foces Morán

 Concentrator (HUB)  Creates a unique collision and broadcast domain  All nodes share the physical medium  As though it were a single cable shared by all nodes  Virtually not used today  Operates at the physical level (OSI level 1) ©2010 Prof. José María Foces Morán

 Conmutador (SWITCH)  Supports several “ communications” at the same time  Several two-node pairs may opt to the full bandwidth  Most common case today  These devices learn the MAC addresses of the nodes as they initiate communication  Operates at the level 2 ©2010 Prof. José María Foces Morán

 Switch, basic functions:  MAC Address learning ▪ Keeps a table that associates port number and MAC: Content Addressable Memory  Filtering  Forwarding ©2010 Prof. José María Foces Morán

 A switched LAN with two segments  Uplink :  A special port that aggregates traffic  Higher bandwidth than the other ports ▪ 1000-BASE-T over CAT6 twisted-pair cables ▪ Gigabit Ethernet over MM (Multi Mode) fiber optics ©2010 Prof. José María Foces Morán

 IP Router:  Works at the internetwork level (OSI no. 3)  PDU: Forwards IP packets  Used to create internetworks  Functions  IP forwarding  DHCP server  NAT/PAT  Firewall ©2010 Prof. José María Foces Morán

 Each IP address is 32 bits in length  Four bytes a.b.c.d: ▪ Decimal ▪ Hex 0x0 – 0xff  Hierarchical, two parts: ▪ Network number ▪ Example/24: 24 bits ▪ Node number: ▪ 32 – 24 = 8  Two special cases ▪ Broadcast: ▪ Loopback: ©2010 Prof. José María Foces Morán

▪ IP address types: ▪ Classful  A, B y C, etc. ▪ CLASSLESS  CIDR/VLSM ▪ Private ranges  For use within an organization ▪ Public  For addressing in the general Internet ▪ We will explain how to calculate the network number, etc ©2010 Prof. José María Foces Morán

▪ Each node has two addresses: ▪ MAC (Its network interface card, NIC) ▪ IP address ▪ How are these addresses related? ▪ Address Resolution Protocol ▪ ARP keeps the relation between the two up-to-date ▪ Play with the arp –a command in your system ©2010 Prof. José María Foces Morán

 Discover the network configuration of your system  Operating system name  IP address  This system’s NICs MAC addresses  The network mask  Our access router (Default router)  Arp table  Name server ©2010 Prof. José María Foces Morán

 Boot your system to Linux  Login into your system:  The instructor will provide user/passwd  Request a shell (A terminal or command processor)  Which system is this? Type the following command after the shell prompt:  $ uname –a Linux llull #1 SMP Thu Aug 19 03:44:10 UTC 2010 i686 GNU/Linux  The name of this node  $ hostname llull ©2010 Prof. José María Foces Morán

 The man command offers you the manual page of the indicated command:  $ man uname  Other Unix useful commands:  $ ls –l  $ pwd  $ cat /etc/services  $ more /etc/hosts  $ exit  $ netstat –a | grep SOCK | more ©2010 Prof. José María Foces Morán

 Your system may have more than one installed  $ man ifconfig  $ ifconfig eth0 Link encap:Ethernet HWaddr 90:e6:ba:cd:96:d9 inet addr: Bcast: Mask: inet6 addr: fe80::92e6:baff:fecd:96d9/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:498 errors:0 dropped:0 overruns:0 frame:0 TX packets:418 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:47523 (46.4 KiB) TX bytes:54582 (53.3 KiB) Interrupt:220 Base address:0x2000  What do the different fields mean? Consult the manual page, lookup the following fields:  Link encap: Ethernet  Hwaddr:  inet addr:  Bcast:  Mask: ©2010 Prof. José María Foces Morán

 $ netstat –a Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 *:nfs *:* LISTEN tcp 0 0 *:afpovertcp *:* LISTEN tcp 0 0 *:swat *:* LISTEN tcp 0 0 *:36938 *:* LISTEN tcp 0 0 *:sunrpc *:* LISTEN tcp 0 0 *:56501 *:* LISTEN tcp 0 0 localhost:ipp *:* LISTEN tcp 0 0 localhost:smtp *:* LISTEN tcp 0 0 *:59514 *:* LISTEN tcp 0 0 *:26 *:* LISTEN tcp 0 0 llull.local: :49699 ESTABLISHED tcp6 0 0 [::]:netbios-ssn [::]:* LISTEN tcp6 0 0 [::]:www [::]:* LISTEN ©2010 Prof. José María Foces Morán

Ejecutad este comando antes de continuar: $ PATH=$PATH:/usr/sbin:/sbin arp -v Address HWtype HWaddress Flags Mask Iface Time-Capsule-Augustus-A ether 00:24:36:a2:e4:50 C eth0 Entries: 1Skipped: 0Found: 1 arp -vn Address HWtype HWaddress Flags Mask Iface ether 00:24:36:a2:e4:50 C eth0 Entries: 1Skipped: 0Found: 1 ©2010 Prof. José María Foces Morán

$ man ping Packet Internet Groper test IP connectivity (OSI level 3) ping paloalto.unileon.es PING paloalto.unileon.es ( ) 56(84) bytes of data. 64 bytes from paloalto.unileon.es ( ): icmp_seq=1 ttl=255 time=0.266 ms 64 bytes from paloalto.unileon.es ( ): icmp_seq=2 ttl=255 time=0.121 ms ©2010 Prof. José María Foces Morán

llull:/home/chema# traceroute paloalto.unileon.es traceroute to paloalto.unileon.es ( ), 30 hops max, 40 byte packets 1 paloalto.unileon.es ( ) ms ms ms llull:/home/chema# traceroute traceroute to ( ), 30 hops max, 40 byte packets 1 Time-Capsule-Augustus-Aurelius.local ( ) ms ms ms 2 n unileon.es ( ) ms ms ms 3 n unileon.es ( ) ms ms ms 4 GE EB-Valladolid0.red.rediris.es ( ) ms ms ms 5 CAL.SO6-1-1.EB-IRIS4.red.rediris.es ( ) ms ms ms ©2010 Prof. José María Foces Morán

 $ route –a route -v Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface * U eth0 default Time-Capsule-Au UG eth0 route -vn Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface U eth UG eth0 ©2010 Prof. José María Foces Morán

 What’s the purpose of the following files?  ( See $ man hosts for example)  /etc/hosts  /etc/services  /etc/networks ©2010 Prof. José María Foces Morán

 Determine the following network configuration parameters of your system: ① Your network access NIC’s MAC address ② Your local net’s default router ip address ③ Your NIC’s network mask ④ Which type if your IP address, A, B or C? ▪ Determine the first high order bits of the IP address ▪ Class A: MSb is a 0 ▪ Bit 31 is a 1 and bit 30 is a 0 ▪ Bit 31 is a 1, bit 30 is a 1 and bit 29 is a 0 ©2010 Prof. José María Foces Morán

 Use your browser to access then, discover how this new connection appears in the output of the following command:  $ netstat –a | more  Which local and remote ports make up this connection? ©2010 Prof. José María Foces Morán

 Required/recommended computing infrastructure for completing the CN Labs  A standard Windows-XP or Windows-7 installation ▪ Test basic IP configuration commands ▪ Install OpNet Simulator, student version  Ubuntu Linux ▪ Basic IP configuration, routing, DNS client ▪ Java Compiler and Runtime + IDE ▪ Wireshark Network Analyzer ©2010 Prof. José María Foces Morán