OV 8 - 1 Copyright © 2013 Logical Operations, Inc. All rights reserved. LAN Infrastructure ...
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Transcript of OV 8 - 1 Copyright © 2013 Logical Operations, Inc. All rights reserved. LAN Infrastructure ...
OV 8 - 1Copyright © 2013 Logical Operations, Inc. All rights reserved.
LAN Infrastructure
Switching Static IP Routing Dynamic IP Routing Virtual LANs Plan a SOHO Network
OV 8 - 2Copyright © 2013 Logical Operations, Inc. All rights reserved.
Switches and Network Performance
Client 1 Server 1
Server 2 Client 2
Eight-port switch
OV 8 - 3Copyright © 2013 Logical Operations, Inc. All rights reserved.
Types of Switches
Switch Type Description
Cut-through
A switch that forwards a data packet as soon as it receives it; no error checking or processing of the packet is performed. This switch performs the address table lookup immediately upon receiving the destination address field in the packet header.
Fragment-freeA switch that scans the first 64 bytes of each packet for evidence of damage by a collision. If no damage is found, it forwards the packet; otherwise, discards it.
Store-and-forwardA switch that calculates the CRC value for the packet’s data and compares it to the value included in the packet. If they match, the packet is forwarded.
MultilayerA multilayer switch that performs both routing and switching functions. This type of switch is relatively new, and there is no industry standard to define what qualifies as a multilayer switch.
Content
A switch that is used for load balancing among server groups and firewalls, and web cache and application redirection. Content switches are often referred to as 4-7 switches as they primarily work on Layers 4 and 7 of the OSI model.
OV 8 - 4Copyright © 2013 Logical Operations, Inc. All rights reserved.
Circuit Switching Networks
Modem Modem
Path built when circuit is establishedPath built when circuit is established
OV 8 - 5Copyright © 2013 Logical Operations, Inc. All rights reserved.
Packet Switching Networks
Each packet finds its own route
Each packet finds its own route
OV 8 - 6Copyright © 2013 Logical Operations, Inc. All rights reserved.
Virtual Circuit Switching
Each packet carries a VCI on
a virtual path
Each packet carries a VCI on
a virtual path
OV 8 - 7Copyright © 2013 Logical Operations, Inc. All rights reserved.
Cell Switching Networks
Blank data fills the celluntil it reaches its fixed size
Blank data fills the celluntil it reaches its fixed size
OV 8 - 8Copyright © 2013 Logical Operations, Inc. All rights reserved.
Routing
Source DestinationBest path for sending the packetBest path for sending the packet
OV 8 - 9Copyright © 2013 Logical Operations, Inc. All rights reserved.
Static Routing
Source
Destination
209.16.88.4
200.200.200.200
R2
R1
Static route used to forward packets
Static route used to forward packets
209.16.88.0
DestinationRouter
200.200.200.0
R2
R1
IP Routing Table
OV 8 - 10Copyright © 2013 Logical Operations, Inc. All rights reserved.
Types of Routers
Router Type Description
Access routersRouters used in SOHO networks. They are located at customer sites and are inexpensive.
Distribution routers
Routers that collect data from multiple access routers and redistributes them to a enterprise location such as a company’s headquarters. The routing capabilities of a distribution router is higher than that of access routers.
Core routersCore routers are located at the center of the network backbones. They are used to connect multiple distribution routers located in different buildings to the backbone.
OV 8 - 11Copyright © 2013 Logical Operations, Inc. All rights reserved.
Routers vs. Switches
Switches: Use MAC addresses, which limits communication to adjacent networks Cannot determine data type
Routers: Use network maps, which enables communication with distant networks Can read port numbers and determine data type
OV 8 - 12Copyright © 2013 Logical Operations, Inc. All rights reserved.
Routing Tables
OV 8 - 13Copyright © 2013 Logical Operations, Inc. All rights reserved.
Routing Table Entries
UnicastUnicast
Default gateway forlocal loopback
Default gateway forlocal loopback
Network interface card
Network interface card
Local broadcastLocal broadcast
Local subnetLocal subnet
MulticastMulticast
Internetwork broadcast
Internetwork broadcast
OV 8 - 14Copyright © 2013 Logical Operations, Inc. All rights reserved.
Routing Entry Components
Network ID of destinationNetwork ID
of destinationMask for this entryMask for this entry
Address offirst hop
Address offirst hop
Local portaddress
Local portaddress
Route cost(in host)
Route cost(in host)
OV 8 - 15Copyright © 2013 Logical Operations, Inc. All rights reserved.
The route Command
Command Function
Route print Display the routing table entries.
Route add Add static entries.
Route delete Remove static entries.
Route change Modify an existing route.
Route –pMakes the specified route persistent across reboots, when used in conjunction with the add command.
Route -f Clears a routing table of all entries.
OV 8 - 16Copyright © 2013 Logical Operations, Inc. All rights reserved.
The Routing Process
Destination IP address does not change
Destination IP address does not change
MAC address changes on each hop
MAC address changes on each hop
Source 100.1.10.19
Destination 200.6.42.7
Subnet 1 Subnet 2 Subnet 3
OV 8 - 17Copyright © 2013 Logical Operations, Inc. All rights reserved.
Autonomous Systems
Leader of the autonomous system
Leader of the autonomous system
A2 A3
A4
A5
A1
AS1
B2
AS2
C1
C2 C3
AS3
Dest Path
B1 AS2B2 AS2B3 AS2B4 AS2
Dest Path
C1 AS3
C2 AS3
C3 AS3
B1 Table
C1 Table
Dest Path
A1 AS1A2 AS1
A3 AS1
A4 AS1
A1 Table
A5 AS1
Inter-domain RoutingInter-domain Routing
Intra-domain RoutingIntra-domain Routing
OV 8 - 18Copyright © 2013 Logical Operations, Inc. All rights reserved.
Router Roles in Autonomous Systems
Interior routers on AS1
Interior routers on AS1
Routers on AS3 are exterior to AS1Routers on AS3 are exterior to AS1
Border routersbetween AS1
and AS3
Border routersbetween AS1
and AS3
Autonomous System 1
Autonomous System 2
Autonomous System 3
OV 8 - 19Copyright © 2013 Logical Operations, Inc. All rights reserved.
Routing Methods in Autonomous Systems
Routing Method Description
Inside an autonomous system
When routing inside an autonomous network, data transmission begins at a workstation and does not leave the AS. That means that when any node sends data, it can send it only to a node on the same local network. Nodes use ARP to obtain the local destination’s MAC address.
Between adjacent networks
Adjacent networks share border routers, and because any router inside an AS knows a direct path to the adjacent network, it knows how to deliver data to the correct border router.
Between distant networks
Distant networks are not directly aware of the location of a destination network. You have accessed a distant network if you have sent a request to the Internet for a web page.
OV 8 - 20Copyright © 2013 Logical Operations, Inc. All rights reserved.
Dynamic Routing
Routers perform route discovery operations. Routers transmit data to adjacent routers. Routing entries are dynamically created. Dynamically built routing tables show an accurate picture of a network as it is
updated more often.
OV 8 - 21Copyright © 2013 Logical Operations, Inc. All rights reserved.
Distance-Vector Routing
Distance denoted by hop countDistance denoted by hop countRouting information shared
among neighborsRouting information shared
among neighbors
To Cost
A 0B 5C 2D 3E 6
Next
---CC
Routing Table A
To Cost
A 3B 8C 5D 0E 9
Next
-AA-A
Routing Table D
To Cost
A 5B 0C 4D 8E 3
Next
---A-
Routing Table B
To Cost
A 6B 3C 4D 9E 0
Next
C--C-
Routing Table E
To Cost
A 2B 4C 0D 5E 4
Next
---A-
Routing Table C
A B
D E
C
3
2 4
5
3
4
OV 8 - 22Copyright © 2013 Logical Operations, Inc. All rights reserved.
Link-State Routing
Floods routing information to all routers within a network. Attempts to build and maintain a more complex route database. Broadcasts small updates and converge quickly. More expensive to implement. OSPF implements link-state routing.
OV 8 - 23Copyright © 2013 Logical Operations, Inc. All rights reserved.
Path-Vector Routing
Leader of the autonomous system
Leader of the autonomous system
A2 A3
A4
A5
A1
AS1
B2
AS2
C1
C2 C3
AS3
Dest Path
B1 AS1B2 AS1B3 AS1B4 AS1
Dest Path
C1 AS3
C2 AS3
C3 AS3
B1 Table
C1 Table
Dest Path
A1 AS1A2 AS1
A3 AS1
A4 AS1
A1 Table
A5 AS1
OV 8 - 24Copyright © 2013 Logical Operations, Inc. All rights reserved.
Route Convergence
Network becomesunreachable
Network becomesunreachable
Still thinks routeis good
Still thinks routeis good
Convergence
Change
OV 8 - 25Copyright © 2013 Logical Operations, Inc. All rights reserved.
Routing Loops
Updates the routingtable of the link
being down
Updates the routingtable of the link
being downAssumes that Router Bhas an alternate path
Assumes that Router Bhas an alternate path
A B C
OV 8 - 26Copyright © 2013 Logical Operations, Inc. All rights reserved.
Count-to-Infinity Loops
Occur when a router or network goes down and one of the other routers does not realize that it can no longer reach the route
Cause incorrect information broadcast
OV 8 - 27Copyright © 2013 Logical Operations, Inc. All rights reserved.
Router Discovery Protocols
Protocol Description
RIPA distance-vector routing protocol that is easy to configure, works well inside simple autonomous systems, and is best deployed in small networks with a fewer numbers of routers and in a non-dynamic environment.
RIP v2 RIP v2 enhances RIP by supporting next hop addressing, authentication, subnet mask, and multicast addressing.
BGPA path-vector routing protocol used to establish routing between ISPs. BGP is the routing protocol used to connect Internet backbones. BGP maintains a table of IP networks among autonomous systems.
IGRP A distance-vector routing protocol developed by Cisco® as an improvement over RIP and RIP v2.
EIGRPA proprietary routing protocol by Cisco and considered a hybrid type protocol. It includes features that support VLSM and classful and classless subnet masks.
OSPFA protocol that is used to accomplish link-state routing. Each OSPF router uses the information in its database to build the shortest possible path to destinations on the internetwork.
IS-IS
A link-state routing protocol that is natively an ISO network layer protocol. IS-IS is similar to OSPF (they both use Dijkstra’s algorithm) but IS-IS is able to support more routers than OSPF and does not support only a specific type of network address.
OV 8 - 28Copyright © 2013 Logical Operations, Inc. All rights reserved.
STP
STP establishes a cross-linked structure between branches
OV 8 - 29Copyright © 2013 Logical Operations, Inc. All rights reserved.
VLANs
Point-to-point connectionsPoint-to-point connections
LAN 1 LAN 2
LAN 3
VLAN
OV 8 - 30Copyright © 2013 Logical Operations, Inc. All rights reserved.
Types of VLANs
Type Computers are Configured to a VLAN Based on
Port-based VLANsThe ports that are a part of the VLAN. For example, in a switch with five ports, ports 1, 2, and 3 can be configured to belong to VLAN A and ports 4 and 5 belong to VLAN B.
MAC address-based VLANs
The MAC address of the computers. Switches are configured to identify the MAC addresses of individual computers connected to it. These MAC addresses are grouped to form the VLAN.
Subnet-based VLANs
The IP subnets that they belong to. The IP addresses are used only as references to identify computers that are to be configured to the VLAN.
OV 8 - 31Copyright © 2013 Logical Operations, Inc. All rights reserved.
VLAN Switch Functions
Subnet 1 Subnet 2 Subnet 3
OV 8 - 32Copyright © 2013 Logical Operations, Inc. All rights reserved.
VTP
VTP advertises switching information to all switches on a network
VTP advertises switching information to all switches on a network
D E
F
A B
C
A B
C
D E
F
OV 8 - 33Copyright © 2013 Logical Operations, Inc. All rights reserved.
SOHO Networks
Devices in SOHO networks
Devices in SOHO networks
OV 8 - 34Copyright © 2013 Logical Operations, Inc. All rights reserved.
SOHO Network Hardware
The list of requirements to implement a SOHO network are: 1 to 10 computers that are to be connected.Specialized connectivity devices.Printers, fax machines, access points, and biometric devices.An ADSL modem to connect to the Internet.For a wired SOHO, you need connecting cables of a length of 100 to 200 meters.
OV 8 - 35Copyright © 2013 Logical Operations, Inc. All rights reserved.
Reflective Questions
1. Of the LAN infrastructure technologies discussed in this lesson (bridges, switches, static routing, dynamic routing, filtering, and VLANs), which ones do you expect to work with the most? Why?
2. What do you see as the pros and cons of implementing static routing versus dynamic routing?