Topic2-Part I Modules6-7.pdf

Part I Module 6: TCP/IP Protocol Suite and IP Addressing 1 6.1 TCP/IP 2 2 Application Layer 3 Transport Layer The primary duty of the transport layer is to provide end-to-end control and reliability as data travels through this cloud. 4 Internet Layer 5 Network Access Layer 6 Internet Architecture U...

Part I Module 6: TCP/IP Protocol Suite and IP Addressing 1 6.1 TCP/IP 2 2 Application Layer 3 Transport Layer The primary duty of the transport layer is to provide end-to-end control and reliability as data travels through this cloud. 4 Internet Layer 5 Network Access Layer 6 Internet Architecture Users see TCP/IP Cloud Physical Details Hidden from Users 7 6.2 Internet Addresses 8 8 IP addressing Consecutive Decimal and Binary Values 9 Network and Host Addressing Network and Host Addressing 10 Network address – Used to identify the network itself The only time that the host numbers matter is when the data is on the local area network. IP address Network address 11 Classful addresses 65534 0 and 127 are reserved http://en.wikipedia.org/wiki/Classful_network http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Internet-Protocols.html 12 Address class prefixes 13 Classes D and E The Class D address class was created to enable multicasting. A multicast address is a unique network address that directs packets with that destination address to predefined groups of IP addresses. Therefore, a single station can simultaneously transmit a single stream of data to multiple recipients. A Class E address has been defined. However, the IETF reserves these addresses for its own research. No Class E addresses have been released for use in the Internet. The first four bits are 1111. The first octet range is 11110000 to 11111111, or 240 to 255. 14 IP address Range 15 Network and Broadcast addresses Network Address – Used to identify the network itself The only time that the host numbers matter is when the data is on the local area network. IP address Network address 16 Broadcast Address Broadcast address 17 Broadcast Transmission 176.10.16.255 Unicast Trasmission 176.10.16.1 18 Public and Private IP addresses Private IP addresses are another solution to the problem of the impending exhaustion of public IP addresses. However, private networks that are not connected to the Internet may use any host addresses, as long as each host within the private network is unique. Connecting a network using private addresses to the Internet requires translation of the private addresses to public addresses. This translation process is referred to as Network Address Translation (NAT). A router usually is the device that performs NAT. 19 Using private addresses in the WAN 20 Subnetting o Subnetting a network means to use the subnet mask to divide the network and break a large network up into smaller, more efficient and manageable segments, or subnets. o An example would be the U.S. telephone system which is broken into area codes, exchange codes, and local numbers. o Subnet addresses include the network portion, plus a subnet field and a host field. o The subnet field and the host field are created from the original host portion for the entire network. 21 22 Subnet Mask 23 Establishing the subnet mask address 24 Quick Reference Subnetting chart All-zeros subnet can be used. All-ones subnet are discourage. http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_not 25 e09186a0080093f18.shtml Applying the subnet mask Three bits to the subnet field = 8 subnets with 32 hosts per subnet. Start with zero (0) when numbering subnets. The first subnet is always referenced as the zero subnet. 192.168. 10.0 /24 00000000 /27 00100000 /27 01000000 /27 01100000 /27 10000000 /27 10100000 /27 11000000 /27 11100000 /27 26 6.3 Obtaining an IP address 27 27 Assigning IP addresses 28 Static assignment of an IP address 29 RARP IP address assignment （Reverse Address Resolution Protocol) A network device, such as a diskless workstation, might know its MAC address but not its IP address. RARP allows the device to make a request to learn its IP address. Devices using RARP require that a RARP server be present on the network to answer RARP requests. RARP Request 30 Read more about RARP: https://www.techtarget.com/searchnetworking/definition/Reverse-Address-Resolution-Protocol RARP packet format 31 BOOTP IP address assignment The bootstrap protocol (BOOTP) operates in a client-server environment and only requires a single packet exchange to obtain IP information. However, unlike RARP, BOOTP packets can include the IP address, as well as the address of a router, the address of a server, and vendor-specific information BOOTP Request 32 BOOTP Packet Format 33 DHCP IP address management Dynamic host configuration protocol (DHCP) is the successor to BOOTP. Unlike BOOTP, DHCP allows a host to obtain an IP address dynamically without the network administrator having to set up an individual profile for each device. What required when using DHCP is a defined range of IP addresses on a DHCP server. As hosts come online, they contact the DHCP server and request an address. The DHCP server chooses an address and leases it to that host. DHCP Request 34 Address Resolution Protocol (ARP) In TCP/IP communications, a datagram must contain both a destination MAC address and a destination IP address. These addresses must match the destination's MAC and IP addresses. How does a host know the destination's MAC address? Address Resolution Protocol (ARP), which can automatically obtain MAC addresses for local transmission. 35 Two ways that devices can gather MAC addresses: 1. One way is to monitor the traffic that occurs on the local network segment. So as data is transmitted on the network, the address pairs populate the ARP table. 2. Another way to broadcast an ARP request. ARP tables are stored in RAM memory. When a source determines the IP address for a destination, it then consults the ARP table in order to locate the MAC address for the destination. LAN Transmission Address Resolution 36 The ARP Process 37 Non-local Address Resolution 38 ARP VS RARP 39 Default Gateway The default gateway is a host option where the IP address of the router interface is stored in the network configuration of the host. The source host compares the destination IP address and its own IP address to determine if the two IP addresses are located on the same segment. If the receiving host is not on the same segment, the source host sends the data using the actual IP address of the destination and the MAC address of the router. The MAC address for the router can be learned by ARP. If the default gateway on the host or the proxy ARP feature on the router is not configured, no traffic can leave the local area network. 40 Part I Module 7: Routing Fundamentals 41 7.1 Routed Protocol 42 42 Routed protocols A routed protocol allows the router to forward data between nodes on different networks. Some protocols, such as IPX, require only a network number. These protocols use the MAC address of the host for the host number. Other protocols, such as IP, require an address with a network portion and a host portion. These protocols also require a network mask to differentiate the two numbers. 43 IP as a routed protocol IP is the most widely used implementation of a hierarchical network-addressing scheme Routed protocol 44 10.1.13 Packet propagation and switching within a router 45 Router Protocol Stripping See web site 46 7.2 IP Routing Protocols 47 47 Routing Overview 48 Routing Metrics 49 Routing vs. Switching 50 ARP Tables and Routing Tables 51 Routed versus routing Routing protocol Routed protocol A routed protocol is a protocol by which data can be routed. Routed protocol are IP, AppleTalk, and IPX. In this kind of protocols we require an addressing scheme and subnetting. A routing protocol is different and is only used between routers. It makes possible for routers to build and maintain routing tables 52 Interior and Exterior Gateway Protocols 53