Broadband in data can refer to broadband networks or broadband Internet and may have the same meaning as above, so that data transmission over a fiber optic cable would be referred to as broadband as compared to a telephone modem operating at 56,000 bits per second. However, a worldwide standard for what level of bandwidth and network speeds actually constitute Broadband have not been determined.[1]However, broadband in data communications is frequently used in a more technical sense to refer to data transmission where multiple pieces of data are sent simultaneously to increase the effective rate of transmission, regardless of data signaling rate. In network engineering this term is used for methods where two or more signals share a medium.[2] Broadband Internet access, often shortened to just broadband, is a high data rate Internet accesstypically contrasted with dial-up access using a 56k modem.Dial-up modems are limited to a bitrate of less than 56 kbit/s (kilobits per second) and require the full use of a telephone linewhereas broadband technologies supply more than double this rate and generally without disrupting telephone use.

Specific OutcomesDifferentiate between open and proprietary protocolsProvide and overview of TCP/IP and its various componentsExplain how and why the different Classes of IP addresses are allocated / managedDemonstrate how a Class B IP address may be subnetted and explain why this may be desirableExplain how an IP packet is routed across several routersCompare and contrast IP routing to Ethernet switchingProtocols focusing on TCP/IP

Protocol Types

Protocols and Data Transmission NetBEUINetBEUIRouterNon-Routable

Types of Data Transmission

Common ProtocolsTransmission Control Protocol/Internet Protocol (TCP/IP)Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX)NetBIOS Enhanced User Interface (NetBEUI)AppleTalk

Routed Protocols (TCP/IP) Segment 1Segment 2TCP/IPTCP/IPWindows ClientWindows Client

Routed Protocols (IPX/SPX) Segment 1Segment 2IPX/SPXIPX/SPXNetWare ClientWindows 2000Server

NetBeui

Appletalk

TCP/IPThe Communication ProcessTCP/IP LayersIdentifying Applications

Communication Process

TCP/IP Layers

TCP/IP Protocol SuiteTransmission Control Protocol (TCP)User Datagram Protocol (UDP)Internet Protocol (IP)Internet Control Message Protocol (ICMP)Internet Group Management Protocol (IGMP)Address Resolution Protocol (ARP)TCP/IP Utilities

TCP

UDP

IP

ICMP

IGMP

ARP

Diagnostic UtilitiesConnectivity UtilitiesServer-basedSoftwareTCP/IP Printing ServiceInternet InformationServicesTCP/IP Utilities

Data Flow

IPRouting

Data Transfer Across Routers

wxyzClass ANetwork IDHost IDClass BNetwork IDHost IDClass CNetwork IDHost IDDifferent Classes of Addresses

Decimal to Binary Representation

Different Class of AddressClass A Net.Node.Node.Node Leading bit = 0, Max: 126 Networks and 16777214 NodesClass B Net.Net.Node.Node Leading bit = 10 Max 16384 Networks and 65534 Nodes (Note network decimal range from 128 191)Class C Net.Net.Net.Node Leading bit = 110 Max 2097152 Networks and 254 Nodes (Note network decimal from 192 223)127 is reserved for loopback test: 127.0.0.1

Different Class of Address

Address ClassNetwork BitsHosts BitsDecimal Address RangeClass A8 bits24 bits1-126Class B16 bits16 bits128-191Class C24 bits8 bits192-223

Leading bits of network addressClass A NetworkClass C NetworkClass B NetworkLeading bit is always zero (0)Leading bit is always one and zero (10)Leading bit is always one, one zero (110)RouterIncoming packet destined for network 01010111 (87), the router only has to read the first bit to know which of its three routes to forward it on

SubnetsSubnet Masks Determining Local and Remote HostsSubnet Masks

Subnetting and Routers

Determining Local and Remote Hosts

Subdividing a Network

Step 1:Determine how many network IDs are required?How many subnets will I need?Unique network ID is required for:Each subnetEvery wide area network (WAN) connection

Subnetting Process

Subdividing a Network

Step 2:What are the maximum number of host IDs youll need on each subnet?Each TCP/IP computer interface cardEach TCP/IP printer network interfaceEach router interface on each subnet. If router connected to two subnets; the router requires two host IDs two IP addresses (see next diagram)Sub-netting Process

Subdividing a Network

Decimal to BinaryQuick class exercise: (3 minutes)Take 167.20.16.1 and work out the binary equivalent

Decimal to BinaryAnswer in progress: 2 2 2 2 2 2 2 2 1 0 1 0 0 1 1 1 __________________________________________________ 128 + 0 + 32 + 0 + 0 + 4 + 2 + 1 = 167IP Address: 10100111

76543210

Decimal to BinaryAnswer:16720 16 1IP Address: 10100111 00010100 00010000 00000001

Decimal to BinaryNow add Subnet Mask: 255.255.0.0 (or class B) 16720 16 1IP Address: 10100111 00010100 00010000 00000001Subnet Mask:11111111 11111111 (00000000 00000000)AND the two numbers:10100111 00010100

Decimal to BinaryNow add Subnet Mask: 255.255.0.0 (or class B) 16720 16 1IP Address: 10100111 00010100 00010000 00000001Subnet Mask:11111111 11111111 (00000000 00000000)AND the two numbers:10100111 00010100Interested in this part:Network PortionNot concerned with this part

Step 3:Consider host 167.20.16.1 with subnet mask 255.255.0.0 (class B) such as Rhodes UniversityIP Address: 10100111 00010100 00010000 00000001Subnet mask: 11111111 11111111 00000000 00000000Network ID: 10100111 00010100Remember that subnet mask 1 bits correspond to network ID bit in the IP address.

Subnetting Process

Step 3: (contd)We decide to add some bits to the subnet mask, increasing the bits available for the network ID and thus create a few more network combinationsNote new subnet mask is:11111111 11111111 11100000 00000000Note because of the 3 extra bits, we have 8 different network IDs.Network IDs10100111 00010100 000(167.20.0) 10100111 00010100 001 (167.20.32)10100111 00010100 010(167.20.64) 10100111 00010100 011 (167.20.96)10100111 00010100 100(167.20.128) 10100111 00010100 101 (167.20.160)10100111 00010100 110(167.20.192) 10100111 00010100 111 (167.20.224)

Subnetting Process

To summarize the preceding example using decimal notation:By applying the subnet mask of 255.255.224.0 to network ID 167.20, you create 8 new network Ids: (167.20.0, 167.20.32, 167.20.64, 167.20.96, 167.20.128, 167.20.160, 167.20.192, 167.20.224)Note: If you used only two instead of three additional bits in the subnet mask,We would only have four subnetsIn the case of two additional bits, the network IDs would be10100111 00010100 00 (167.20.0)10100111 00010100 01 (167.20.64)10100111 00010100 10 (167.20.128)10100111 00010100 11 (167.20.192)Therefore we must always use enough additional bits in the subnet mask to create the desired numbers of subnets, though still allow for enough hosts on each subnet.

Lets look at Rhodes UniversityRhodes has a scarce Class B Internet Address (privilege)Rhodes Unique IP address is:146.231 therefore all IP addresses at Rhodes will have the network component of 146.231The default Class B subnet mask is:255.255 or in binary 11111111 . 11111111Rhodes can have up to 65,534 hosts if they do not divide or steal some of these host bits, to divide the network up into subnets.Rhodes definitely does not need to cater for 65,534 hosts therefore the decision to divide up the network into different subnets, for all the previously discussed reasons.

Rhodes continuedRhodes administrators decide to allocate 5 host bits to divide up the University network into subnets.11111111 . 11111111 . 11111000 . 00000000How many subnets does this give the University?2 to the power of 5 = 32 therefore Rhodes can have up to 32 subnets.How many hosts can Rhodes have on each subnet?2 to the power of 11 (-2) = 2,046What is the Rhodes Subnet Mask255 . 255 . 248 . 0

Rhodes continuedWhat are the subnets that are created?Calculated manually, list all the combos of the additional bits0000000100 etcetc 00001.3200100etcetc00010.6400101etcetc00011.9600101etcetc00100.128xxxxxetcetc00101.160xxxxxetcetc00110.192xxxxxetc(Very tedious)00111 etcxxxxxetc

Rhodes continuedWhat are the subnets that are created?A shorter, less tedious methodList the additional octet added to the default subnet mask in decimal notation.Convert the rightmost 1 bit of this value to decimal notation, which is the incremental value of each subnet value known as DeltaAppend Delta to the original ID to give the first subnet network IDRepeat previous step for each subnet network ID, incrementing each successive value by Delta

Rhodes continuedRhodes was assigned a class B network of :146.231.0.0We created 32 subnets by taking 5 bits from the host portion (11111000) and the rightmost bit converted to decimal is 8, thus the incremental value is 8There are 2 to the power of 5 subnets created or 32 subnets.The subnets created are:146.231.0146.231.8146.231.56146.231.104146.231.152146.231.200146.231.16146.231.64146.231.112146.231.160146.231.208146.231.24146.231.72146.231.120146.231.168146.231.216146.231.32146.231.80146.231.128146.231.176146.231.224146.231.40146.231.88146.231.136146.231.184146.231.232146.231.48146.231.96146.231.144146.231.192146.231.240146.231.248

Rhodes continuedWhat are the host IDs that we can use?

SubnetFirst IP AddressLast IP Address146.231.0.0146.231.0.1146.231.7.254146.231.8.0146.231.8.1146.231.15.254146.231.16.0146.231.16.1146.231.23.254146.231.24.0146.231.24.1146.231.31.254146.231.32.0146.231.32.1146.231.39.254146.231.40.0146.231.40.1146.231.47.254146.231.48.0146.231.48.1146.231.55.254146.231.56.0146.231.56.1146.231.63.254UP to 248

RoutingSubnet172.30.20.xSubnet172.30.21.xEthernetSwitch 2Server Y172.30.21.86D1-Router E172.30.21.2E1-Router F172.30.21.1F1-Router D172.30.20.1C1-Client PC R172.30.20.47A1-Server X172.30.20.19B1-EthernetSwitch 1Router B connects to 4 subnets via its 4 interfaces (ports)Router ARouter CRouter B

RoutingRouter ARouter CRouter BInterface 1Subnet 172.30.19.x802.11Interface 4172.30.19.111-Subnet172.30.20.xSubnet172.30.21.xRouter BEthernetSwitch 2Server Y172.30.21.86D1-Router E172.30.21.2E1-Router F172.30.21.1F1-Router D172.30.20.1C1-Client PC R172.30.20.47A1-Server X172.30.20.19B1-EthernetSwitch 1Router Bs Interface 1is connected to a point-to-point 802.11 subnet,172.30.19.x

This subnet goes to Router As Interface 4,which has IP address 172.30.19.1and MAC address 11-

Each interface on a router has a differentIP address and data link layer address.

Router ARouter CRouter BInterface 4Subnet 172.30.22.x802.11Subnet172.30.20.xSubnet172.30.21.xRouter BInterface 1172.30.22.921-EthernetSwitch 2Server Y172.30.21.86D1-Router E172.30.21.2E1-Router F172.30.21.1F1-Router D172.30.20.1C1-Client PC R172.30.20.47A1-Server X172.30.20.19B1-EthernetSwitch 1Router Bs interface 4 also connectsTo an 802.11 point-to-point subnet,172.30.22.x.

This reaches Interface 1 on Router C.This interface hasIP address 172.30.22.9and MAC address 21- Routing

Router ARouter CSubnet172.30.20.xSubnet172.30.21.xRouter BRouter BInterface 2EthernetEthernetSwitch 2Server Y172.30.21.86D1-Router E172.30.21.2E1-Router F172.30.21.1F1-Router D172.30.20.1C1-Client PC R172.30.20.47A1-Server X172.30.20.19B1-EthernetSwitch 1Router Bs Interface 2connects to Ethernet subnet172.30.20.x.

This subnet has a single switch.

Other devices on the subnetinclude a single router (D),a single Client PC (R),and a single server (X).Routing

Router ARouter CSubnet172.30.20.xSubnet172.30.21.xRouter BRouter B Interface 3EthernetEthernetSwitch 2Server Y172.30.21.86D1-Router E172.30.21.2E1-Router F172.30.21.1F1-Router D172.30.20.1C1-Client PC R172.30.20.47A1-Server X172.30.20.19B1-EthernetSwitch 1Router Bs Interface 3connects to Ethernet Subnet130.30.21.x

This subnet hasone server (Y)and two routers (E and F)Routing

Router ARouter CArrivingPacketSubnet172.30.20.xSubnet172.30.21.xRouter BEthernetSwitch 2Server Y172.30.21.86D1-Router E172.30.21.2E1-Router F172.30.21.1F1-Router D172.30.20.1C1-Client PC R172.30.20.47A1-Server X172.30.20.19B1-EthernetSwitch 1A packet arrives in Interface 1 of Router B.The router will forward the packet out a different interface.Routing

Router ARouter CSubnet172.30.20.xSubnet172.30.21.xRouter BRouter B Interface 3EthernetInterface 1172.30.22.921-EthernetSwitch 2Server Y172.30.21.86D1-Router E172.30.21.2E1-Router F172.30.21.1F1-Router D172.30.20.1C1-Client PC R172.30.20.47A1-Server X172.30.20.19B1-EthernetSwitch 1Here the packet issent out Interface 3,which connects toSubnet 172.30.21.x

It must be sent toServer Y,Router E, orRouter F.Routing

Router ARouter CSubnet172.30.20.xSubnet172.30.21.xRouter BRouter B Interface 3EthernetInterface 1172.30.22.921-EthernetSwitch 2Server Y172.30.21.86D1-Router E172.30.21.2E1-Router F172.30.21.1F1-Router D172.30.20.1C1-Client PC R172.30.20.47A1-Server X172.30.20.19B1-EthernetSwitch 1For a packet going toServer Y,

The destination IP addressis 172.30.21.86(Server Y, the destination host)

The packet is put in a frame withDestination MAC address D1-(Server Y)Routing

Router ARouter CSubnet172.30.20.xSubnet172.30.21.xRouter BRouter B Interface 3EthernetInterface 1172.30.22.921-EthernetSwitch 2Server Y172.30.21.86D1-Router E172.30.21.2E1-Router F172.30.21.1F1-Router D172.30.20.1C1-Client PC R172.30.20.47A1-Server X172.30.20.19B1-EthernetSwitch 1For a packet going toRouter E, which willtake responsibility for the packet.

The destination IP addressis the IP address ofthe destination host.

The packet is put in a frame withdestination MAC address E1-(Router E).Routing

EthernetLAN 2Site AUnixServerOld NetWareServerInternalRouter YSite BMultiprotocolRouter XEdgeRouter ZTheInternetWWWServerEthernetLAN 3TCP/IPSNATCP/IPIPX/SPXMainframeEthernetLAN 1Most firms have a mix of internetworkingarchitectures (TCP/IP, IPX/SPX, SNA, etc.).

Consequently, most routers are multiprotocolrouters that route the packets ofmultiple architectures.Routing

Ethernet Switching Versus IP RoutingSwitching Table Switch 1PortStation2A1-44-D5-1F-AA-4C7B2-CD-13-5B-E4-655C3-2D-55-3B-A9-4F5D4-47-55-C4-B6-9F5E5-BB-47-21-D3-56

EthernetSwitchingSwitch 2Switch 1Port 5 on Switch 1to Port 3 on Switch 2A1-44-D5-1F-AA-4CSwitch 1, Port 2B2-CD-13-5B-E4-65Switch 1, Port 7Port 7 on Switch 2to Port 4 on Switch 3Ethernet switching is fast and therefore inexpensive.For a destination MAC address,there is only one match in the table.This can be found quickly.The frame is sent out the port listed in that row.

Ethernet Switching Versus IP Routing, ContinuedIP Routing Table Router AInterfaceNetwork160.x.x.x2128.171.x.x1123.x.x.x260.x.x.x2123.x.x.xIP RoutingNetwork60.x.x.xRouter CRouter BRouter AInterface1Interface2Router topologies are meshes.This gives alternative routes.A destination IP address willMatch multiple rows.

Ethernet Switching Versus IP Routing, ContinuedIP Routing Table Router AInterfaceNetwork160.x.x.x2128.171.x.x1123.x.x.x260.x.x.x2123.x.x.xIP RoutingNetwork60.x.x.xRouter CRouter BRouter AInterface1Interface2All matching rows must be found.Then, the best match must be found.This is slow and therefore expensive.

Ethernet Switching Versus IP Routing, ContinuedEthernet (and most other) switching is inexpensive for a given traffic volumeRouter routing is expensive for a given traffic volumeNetwork administrators say Switch where you can; route where you must.

Routing TableRowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface1128.171.0.0255.255.0.0 (/16)47G22172.30.33.0255.255.255.0 (/24)0Local13192.168.6.0255.255.255.0 (/24)12G2Routers Base Routing Decisions on Their Routing Tables.Each Row Represents a Route to a Network or SubnetFor Each Arriving Packet, The Packets Destination IP Address Is Matched Against the Destination Network or Subnet Field in Every Row

Routing Table, ContinuedRowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface1128.171.0.0255.255.0.0 (/16)47G22172.30.33.0255.255.255.0 (/24)0Local13192.168.6.0255.255.255.0 (/24)12G2Each Row Represents a Route to a Network or Subnet.All packets to that network or subnet are governed by that one row.So there is one rule for a range of IP addresses. This reduces the number of rows that must be considered.

Masking1. Basic ProcessInformation bit 1 0 1 0Mask bit 1 1 0 0Result 1 0 0 0

3. Example 1IP Address172. 30. 22. 7Mask255. 0. 0. 0 Result172. 0. 0. 02. Common PatternsBinaryDecimal00000000011111111255

4. Example 2IP Address172. 30. 22. 7Mask255. 255. 0. 0 Result172. 30. 0. 0

Routing Table, ContinuedRow 1If Destination IP Address = 172. 30.33.6Mask = 255.255. 0.0Result = 172. 30. 0.0Destination Network or Subnet = 128.171. 0.0No match!RowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface1128.171.0.0255.255.0.0 (/16)47G22172.30.33.0255.255.255.0 (/24)0Local13192.168.6.0255.255.255.0 (/24)12G2

Routing Table, ContinuedRowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface1128.171.0.0255.255.0.0 (/16)47G22172.30.33.0255.255.255.0 (/24)0Local13192.168.6.0255.255.255.0 (/24)12G2Row 2If Destination IP Address = 172. 30. 33.6Mask = 255.255.255.0Result = 172. 30. 33.0Destination Network or Subnet = 172. 30. 33.0This row is a match!

Routing Table, ContinuedRowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface1128.171.0.0255.255.0.0 (/16)47G22172.30.33.0255.255.255.0 (/24)0Local13192.168.6.0255.255.255.0 (/24)12G2Row 3If Destination IP Address = 172. 30. 33.6Mask = Result = Destination Network or Subnet = Is this row is a match?

RoutingFor Each Incoming IP PacketDestination IP address is matched against every row in the routing table.If the routing table has 10,000 rows, 10,000 comparisons will be made for each packet.There can be multiple matching rows for a destination IP address, corresponding to multiple alternative routes.After all matches are found, the best match must be selected.

Routing Table, ContinuedIf only one row matches, it will be selected as the best row match.Destination IP address = 192.168.6.7RowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface3192.168.0.0255.255.0.0 (/16)12G2

Routing Table, ContinuedThe default row always matchesMask 0.0.0.0 applied to anything results in 0.0.0.0This always matches the Network/Subnet value 0.0.0.0The router specified for this row (H) is the default router

RowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface130.0.0.00.0.0.0 (/0)5H3

Routing Table, ContinuedIf there are multiple matches, the row with the longest length of match is selectedThis is Row 7 for 128.171.17.56 (24 bit match)Row 1s length of match is only 16 bitsLonger matches often are routes to a particular subnet within a network

Routing Table, ContinuedIf there are multiple rows with the same lengths of match, the metric column compares alternative routes.If the metric is cost, the smallest metric wins (20)If the metric is speed, the largest metric wins (34)

RowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface5172.29.8.0255.255.255.0 (/24)34F18172.29.8.0255.255.255.0 (/24)20H3

The SituationThe router first evaluated the IP destination address of the arriving packet against all rows and noted the matching rows.The router then selected the best-match row.Now, the router examines the interface and next-hop router fields in the best-match row to determine what to do with the packet.

Interface and Next-Hop RouterRouterForwardingPacketPossibleNext-HopRouterPossibleNext-HopRouterPossibleDestinationHostPacket to Router Bon Interface 5Router ARouter BRouter CIP Subnet onInterface (Port 5)Packet must be sent toa particular host orrouter on the subnetout a particularinterface (port).

Routing Table, ContinuedThe Interface specifies the out port on the router.A subnet is attached to this interface.Next Hop Router (NHR) column specifies a specific NHR on that subnet.For Row 5, send packet to NHR F on the subnet out Interface 1.RowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface5172.29.8.0255.255.255.0 (/24)34F1

Routing Table, ContinuedIf Next-Hop Router Field says Local, Then the destination host in on the subnet attached to the interface (1).Instead of sending the packet to a next-hop router on the subnet, the router will send the packet to its destination address.

RowDestinationNetwork orSubnetMask (/Prefix)Metric(Cost)Next-HopRouterInterface2172.30.33.0255.255.255.0 (/24)0Local1

Routing RecapThe router looks at the destination IP address in the packet.First, the router finds all matching rows.Second, selects the best matching row.Third, sends packet back out the rows specified interface, to the rows specified next-hop router.Begins to process the next packet.

References:

Napier, A., Judd, P., Rivers, O., and Adams, A., (2003)E-Business TechnologiesThomson Course TechnologiesISBN: 0-619-06319-xPanko, R (2005)Business Data Networks and Communications, 5th edition, Prentice HallISBN: 0-13-127315-9SchneiderE-Business, Eighth EditionISBN-13: 978-0-324-78807-5Hogan, F., (2005)Internet Presentation

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