Intro. to Networks This lecture will consist Internet and Ethernet short history Layer model (ISO and IP) Routing and routers Linux routing table PPP short.
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Intro. to Networks
This lecture will consist• Internet and Ethernet short history• Layer model (ISO and IP)• Routing and routers• Linux routing table• PPP short history and purpose• PPP and Linux
Internet & Ethernet Brief history
Internet (http://www.isoc.org/internet/history/)
• 1969 – ARPANET (The Internet origin)
• 1969 – UNIX
• 1972 – Ethernet
• 1989 – WWW
• 1991 – Linux
• 1992 –Mosaic
Internet organization
• ISOC – http://www.isoc.org
• IETF – http://www.ietf.org
• IETF RFCs – http://www.ietf.org/rfc
• IANA – http://www.iana.org
• IAB – http://www.iab.org
• W3C – http://www.w3c.org
Other org. involve in Networks
• ISO – http://www.iso.ch
• ITU – http://www.itu.int
• IEEE – http://www.ieee.org
OSI layers via Internet layers
OSI
• Physical• Data link• Network• Transport• Session• Presentation• Application
IP
• Ethernet hardware• Ethernet• IP stack• TCP/UDP stack
• IP applications
LAN MAC Addresses
• Registration through the IEEE.
• XX-XX-XX-XX-XX-XX
• Vendor register leading XX-XX-XX.
• Example: 3Com register 00-05-1A
• Example: a NIC made by 3Com
• 00-05-1A-0C-01-93
Making LAN
We need 4 component to make LAN
• Cables
• NICs in the PCs or other (e.g. Printers)
• Hubs (Repeaters)
• Switches
Configure NIC
• Use hotplug.
• lspci , lspci -n
• PCI Vendor ID. (on the Internet)
• /lib/modules/<kid>/kernel/drivers/net/
• USB Cable, USB ADSL => USB NIC.
• lsmod
• ifconfig -a
IP v4 Address
• Class A 1.0.0.0-126.0.0.0 7/24
• Class B 128.1.0.0-191.254.0.0 14/16
• Class C 192.0.1.0-223.255.254.0 22/8
• Class D 224.0.0.0-239.255.255.255
• Class E 240.0.0.0-254.255.255.255
IP Network and subnets
• A name for IP based LAN.
• IP Network – mask according to class.
• IP sub network have a smaller mask.
• Example:
• 10.1.0.0, 255.255.0.0 is subnet class A.
Address Resolution Protocol
• RFC 826
• Map LAN MAC into the IP address.
• Dynamic ARP.
• Manual ARP
• Static ARP.
Linux LAN
• ifconfig -a – See your interfaces
• arp -n – See the ARP table
• arp -s ip mac – Set ARP
• route -n
• ip - iproute2 tool
IP routing.
RouterServer
00-05-1B-1A-3C-B4
10.1.14.12410.1.14.110.101.15.110.101.15.73
00-02-B3-1D-5E-87
00-02-BA-13-BC-11
00-02-BA-13-BC-13
Dst 10.101.15.73Src 10.1.14.124Dst MAC 00-02-BA-13-BC-11Src MAC 00-05-1B-1A-3C-B4
IP routing.
RouterServer
00-05-1B-1A-3C-B4
10.1.14.12410.1.14.110.101.15.110.101.15.73
00-02-B3-1D-5E-87
00-02-BA-13-BC-11
00-02-BA-13-BC-13
Dst 10.101.15.73Src 10.1.14.124Dst MAC 00-02-B3-1D-5E-87Src MAC 00-02-BA-13-BC-13
Routing table
• Default Gateway.• Simple example:• Destination Gateway Genmask Flags Metric Ref Use Iface
• 10.1.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
• 0.0.0.0 10.1.0.1 0.0.0.0 UG 0 0 0 eth0
A real route
• RIP – RFC 1058, 1388, 1723
• OSPF - RFC 2178 (v2)
• BGP - RFC 1771 (BGP-4)
• PIM – RFC 2362, 3973
• OSI IS-IS
• IGRP, EIGRP – Cisco.
• Real routers are not just routers!
PPP
• Point to Point Protocol
• IP protocol for connecting PC over phone line.
• Use tty char device for transferring IP packets.
• RFC 1661, RFC 1662 (STD 51)
• HDLC ISO 3309
Why PPP?
• Phone lines.
• Authentication.
• Bandwidth and QoS control
• Dynamic client to ISP mapping.
• Easy configuration VPN.
• Compression option.
• Packets concatenating.
PPP structure
• LCP – Create the PPP link.
• PAP or CHAP authentication.
• HDLC – Octet/Bit stuffed framing
PPP over IP
• L2TP – RFC 2661, RFC 3931 (v3)
• PPTP – RFC 2637
• Server IP instead of phone number.
• Two IP networks with one IP stack
• Need a more complicated routing.
• Possible to work L2TP over PPPoE.
PPP over IP routing
• Simple example:• Destination Gateway Genmask Flags Metric Ref Use Iface
• 132.64.140.2 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0
• 10.1.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
• 0.0.0.0 132.64.140.2 0.0.0.0 UG 0 0 0 ppp0
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