Ccna Lab Manual

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(1)CCNA Lab Guide.

(2) Cisco IOS Introduction General Reading:System Architecture Like a computer, a router has a CPU that varies in performance and capabilities depending on the router platform. Two examples of processors that Cisco uses are the Motorola 68030 and the Orion/R4600. The Cisco IOS software running in the router requires the CPU or processor to make routing and bridging decisions, maintain routing tables, and other system management functions. The CPU must have access to data in memory to make decisions or to get instructions. There are usually four types of memory on a Cisco router: . . . . ROM—ROM is generally the memory on a chip or multiple chips. It is available on a router's processor board. It is read-only, which means that data cannot be written to it. The initial software that runs on a Cisco router is called the bootstrap software and is usually stored in ROM. The bootstrap software is invoked when the router boots up. Flash—Flash memory is located on a processor board SIMM but can be expanded using PCMCIA (removable) cards. Flash memory is most commonly used to store one or more Cisco IOS software images. Configuration files or system information can also be copied to Flash. On some high-end systems, Flash memory is also used to hold bootstrap software. RAM—RAM is very fast memory that loses its information when the system is restarted. It is used in PCs to store running applications and data. On a router, RAM is used to hold IOS system tables and buffers. RAM memory is basically used for all system operational storage requirements. NVRAM—On the router, NVRAM is used to store the startup configuration. This is the configuration file that IOS reads when the router boots up. It is extremely fast memory and is persistent across reboots. Although CPU and memory are required components to run IOS, a router must also have various interfaces to allow packet forwarding. Interfaces are input and output connections to the router that carries data that needs to be routed or switched. The most common types of interfaces are Ethernet and serial. Similar to the driver software on a computer with parallel ports and USB ports, IOS has device drivers to support these various interface types. All Cisco routers have a console port that provides an EIA/TIA-232 asynchronous serial connection. The console port can be connected to a computer's serial connection to gain terminal access to the router. Most routers also have an auxiliary port that is very similar to the console port, but is typically used for modem connection for remote router management. Following Output shows the console output of a new Cisco 3640 router that has just been started. Notice the processor, interface, and memory information that is listed. System Bootstrap, Version 11.1(20)AA2, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1) Copyright (c) 1999 by Cisco Systems, Inc. C3600 processor with 98304 Kbytes of main memory Main memory is configured to 64 bit mode with parity disabled program load complete, entry point: 0x80008000, size: 0xa8d168 Self decompressing the image : ################################################# #################################################################### [OK]. Restricted Rights Legend.

(3) Use, duplication, or disclosure by the Government is subject to restrictions as set forth in subparagraph (c) of the Commercial Computer Software - Restricted Rights clause at FAR sec. 52.227-19 and subparagraph (c) (1) (ii) of the Rights in Technical Data and Computer Software clause at DFARS sec. 252.227-7013.. Cisco Systems, Inc. 170 West Tasman Drive San Jose, California 95134-1706. Cisco Internetwork Operating System Software IOS (tm) 3600 Software (C3640-IS-M), Version 12.2(10), RELEASE SOFTWARE (fc2) Copyright (c) 1986-2002 by Cisco Systems, Inc. Compiled Mon 06-May-02 23:23 by pwade Image text-base: 0x60008930, data-base: 0x610D2000. cisco 3640 (R4700) processor (revision 0x00) with 94208K/4096K bytes of memory. Processor board ID 17746964 R4700 CPU at 100Mhz, Implementation 33, Rev 1.0 Bridging software. X.25 software, Version 3.0.0. SuperLAT software (copyright 1990 by Meridian Technology Corp). 5 Ethernet/IEEE 802.3 interface(s) 1 Serial network interface(s) DRAM configuration is 64 bits wide with parity disabled. 125K bytes of non-volatile configuration memory. 8192K bytes of processor board System flash (Read/Write) 16384K bytes of processor board PCMCIA Slot0 flash (Read/Write). --- System Configuration Dialog --Would you like to enter the initial configuration dialog? [yes/no]:. When a new router is first started, IOS runs an autoinstall process wherein the user is prompted to answer a few questions. IOS then configures the system based on the input provided. After initial setup, the configuration is most commonly modified using the command-line interface (CLI). Other ways of configuring the router include HTTP and network management applications Cisco IOS has three command modes, each with access to different command sets:.

(4) . User mode—This is the first mode a user has access to after logging into the router. The user mode can be identified by the > prompt following the router name. This mode allows the user to execute only the basic commands, such as those that show the system's status. The system cannot be configured or restarted from this mode. Router>. . Privileged mode—This mode allows users to view the system configuration, restart the system, and enter configuration mode. It also allows all the commands that are available in user mode. Privileged mode can be identified by the # prompt following the router name. The user mode enable command tells IOS that the user wants to enter privileged mode. If an enable password or enable secret password has been set, the user needs to enter the correct password or secret to be granted access to privileged mode. An enable secret password uses stronger encryption when it is stored in the configuration and, therefore, is safer. Privileged mode allows the user to do anything on the router, so it should be used with caution. To exit privileged mode, the user executes the disable command. Router#. . Configuration mode—This mode allows users to modify the running system configuration. To enter configuration mode, enter the command configure terminal from privileged mode. Configuration mode has various submodes, starting with global configuration mode, which can be identified by the (config)# prompt following the router name. As the configuration mode submodes change depending on what is being configured, the words inside the parentheses change. For example, when you enter interface configuration submode, the prompt changes to (config-if)# following the router name. To exit configuration mode, the user can enter end or press Ctrl-Z. Router(config)#. Terminal Server Now days it is very difficult to use console cable and access multiple devices as routers and switched which we configure are placed in datacenter, to overcome this problem we use terminal server. This is a single point of management device. A terminal or comm server commonly provides out-of-band access for multiple devices. A terminal server is a router with multiple, low speed, asynchronous ports that are connected to other serial devices, for example, modems or console ports on routers or switches. The terminal server allows you to use a single point to access the console ports of many devices. A terminal server eliminates the need to configure backup scenarios like modems on auxiliary ports for every device. You can also configure a single modem on the auxiliary port of the terminal server, to provide dial-up service to the other devices when network connectivity fails. Below is the pictorial scenario which shows the working of terminal server.

(5) Task 1 Telnet to CCNA Terminal Server at IP address 172.16.50.88 Solution: In Linux Base system such as Ubuntu go to applications then accessories and click on terminal and type “telnet 172.16.50.88” For Windows machine go to run and type “telnet 172.16.50.88”. Task 2 After you telnet into terminal server it will ask you for username and password, use username:student and password:student Solution: telnet 172.16.50.88. +--------------------------------------------------------------------+ | Following commands are available for use at privilege 0. |. | 1).Show Host. |. | 2).Show Sessions. |. | 3).Show Users. |. | 4).Clear Line. |. | 5).Disconnect. |. |. |. | Following CCNA Racks Can be Accessed From This Terminal :-. |. |. 1).CCNA-Rack1. |. |. 2).CCNA-Rack2. |.

(6) |. 3).CCNA-Rack3. |. |. 4).CCNA-Rack4. |. |. 5).CCNA-Rack5. |. |. 6).CCNA-Rack6. |. |. 7).CCNA-Rack7. |. |. 8).CCNA-Rack8. |. |. 9).CCNA-Rack9. |. |. 10).CCNA-Rack10. |. +--------------------------------------------------------------------+. ******************************************************************** *. WELCOME TO ACIT Bangalore. *. *. YOU ARE CONNECTED TO CCNA-TERMINAL 88. *. ******************************************************************** User Access Verification. Username: student Password: CCNA_Term#. Task 3 use show host commands to see the available racks. Solution: CCNA_Term#show host Default domain is not set Name/address lookup uses static mappings. Codes: UN - unknown, EX - expired, OK - OK, ?? - revalidate temp - temporary, perm - permanent NA - Not Applicable None - Not defined. Host. Port. Flags. Rack1-R1. 1026. (perm, OK) 64. IP. 128.0.0.2. Rack1-R3. 1028. (perm, OK) 84. IP. 128.0.0.2. Rack1-SW1. 1029. (perm, OK) 84. IP. 128.0.0.2. Rack1-SW2. 1030. (perm, OK) 84. IP. 128.0.0.2. ..<output omitted>. Task 4 Now access device rack1-r1 Solution:. Age Type. Address(es).

(7) CCNA_Term#rack1-r1 Translating "rack1-r1" Trying Rack1-R1 (128.0.0.2, 1026)... Open % Please answer 'yes' or 'no'. Would you like to enter the initial configuration dialog? [yes/no]:no Press RETURN to get started! Router>. (Note:- At this point we are in device R1 of rack1) Task 5 Lock the session of R1 and come back to terminal server by pressing CTRL+SHIFT+6 X Solution: Router> CCNA_Term#. Task 6 Now open rack1-r2, rack1-r3, rack1-sw1 and rack1-sw2 Solution: CCNA_Term#rack1-r2 Translating "rack1-r2" Trying Rack1-R2 (128.0.0.2, 1027)... Open Press RETURN to get started! Router> CCNA_Term#rack1-r3 Translating "rack1-r3" Trying Rack1-R3 (128.0.0.2, 1028)... Open Press RETURN to get started! Router> CCNA_Term#rack1-sw1 Translating "rack1-sw1" Trying Rack1-SW1 (128.0.0.2, 1029)... Open Press RETURN to get started! switch> CCNA_Term#rack1-sw2 Translating "rack1-sw2" Trying Rack1-SW2 (128.0.0.2, 1030)... Open Press RETURN to get started! switch>. Task 7 Go back to Terminal Server and check the sessions which you have opened by pressing CTRL+SHIFT+6 X.

(8) Solution: CCNA_Term#show sessions Conn Host. *. Address. Byte. Idle Conn Name. 1 rack3-r1. 128.0.0.2. 162. 8 rack3-r1. 2 rack3-r2. 128.0.0.2. 0. 0 rack3-r2. 3 rack3-r3. 128.0.0.2. 0. 0 rack3-r3. 4 rack3-sw1. 128.0.0.2. 39. 0 rack3-sw1. 5 rack3-sw2. 128.0.0.2. 0. 0 rack3-sw2. (Note:- In above output you can see that we have opened 5 session. Automatically connection numbers are assigned to every session. So next time if you want to access R1 then we don’t have to press rack1-r1 again it can be simply accessed by pressing it’s current connection number i.e. 1. The Star before 5 shows the current active connection). Task 8 on R1,R2,R3,SW1,SW2 Assign hostname R1,R2,R3,SW1,SW2 respectively Solution: CCNA_Term#1 [Resuming connection 1 to rack1-r1 ... ]. Router>enable Router#config t Enter configuration commands, one per line.. End with CNTL/Z.. Router(config)#hostname R1 R1(config)# CCNA_Term#2 [Resuming connection 2 to rack1-r2 ... ]. Router>enable Router#config t Enter configuration commands, one per line.. End with CNTL/Z.. Router(config)#hostname R2 R2(config)# CCNA_Term#3 [Resuming connection 3 to rack1-r3 ... ]. Router>enable Router#config t Enter configuration commands, one per line. Router(config)#hostname R3 R3(config)#. End with CNTL/Z..

(9) CCNA_Term#4 [Resuming connection 4 to rack1-SW1 ... ]. Switch>enable Switch#config t Enter configuration commands, one per line.. End with CNTL/Z.. Switch(config)#hostname SW1 SW1(config)# CCNA_Term#5 [Resuming connection 5 to rack1-SW2 ... ]. Switch>enable Switch#config t Enter configuration commands, one per line.. End with CNTL/Z.. Switch(config)#hostname SW2 SW2(config)#. Task 9 Go to R1 and Check the available interfaces Solution: On R1: R1#show ip interface brief Interface. IP-Address. OK? Method Status. Protocol. Ethernet0/0. unassigned. YES unset. administratively down down. Ethernet0/1. unassigned. YES unset. administratively down down. Ethernet0/2. unassigned. YES unset. administratively down down. Ethernet0/3. unassigned. YES unset. administratively down down. Serial1/0. unassigned. YES unset. administratively down down. Serial1/1. unassigned. YES unset. administratively down down. Serial1/2. unassigned. YES unset. administratively down down. Serial1/3. unassigned. YES unset. administratively down down. (Note:- Above are the list of interfaces available on router R1 but it may vary as device to device).

(10) Task 9 On R1 assign IP address 10.0.0.1 and use classful subnetmask to interface Ethernet 0/0 and verify your configuration. Solution: On R1: R1# R1#configure terminal Enter configuration commands, one per line.. End with CNTL/Z.. R1(config)#interface ethernet 0/0 R1(config-if)#ip address 10.0.0.1 255.0.0.0 R1(config-if)#no shutdown R1(config-if)#exit *Jul up. 1 00:37:53.867: %LINK-3-UPDOWN: Interface Ethernet0/0, changed state to. *Jul 1 00:37:54.871: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/0, changed state to up R1(config)#exit R1#. (Note:- We Can See that ―no shutdown‖ command has been issued to start the interface. After issuing the command we can see that 2 log massages are appeared on the console, stating that link and line-protocol changed to up.) Verification:. On R1: R1# R1#show ip interface brief Interface. IP-Address. OK? Method. Status. Protocol. Ethernet0/0. 10.0.0.1. YES manual up. Ethernet0/1. unassigned. YES unset. administratively down down. Ethernet0/2. unassigned. YES unset. administratively down down. Ethernet0/3. unassigned. YES unset. administratively down down. Serial1/0. unassigned. YES manual administratively down down. Serial1/1. unassigned. YES unset. up. administratively down down. ...<output omitted>. (Note:- In verification we can see that interface status and line protocol of interface Ethernet 0/0 is UP, also we can see that IP address which we assigned Is there, we should always consider a important note that every UP interface of router which has ip address is assigned defines one whole network, in this case interface Ethernet 0/0 defines the network 10.0.0.0 255.0.0.0, it can be verified with ―show ip route‖ command, therefore we cannot give any ip from this network to any other interface of the this router.).

(11) R1#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B – BGP ,. D - EIGRP, EX - EIGRP external, O – OSPF. IA - OSPF inter area , N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 , E1 - OSPF external type 1, E2 - OSPF external type 2 , i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 , ia - IS-IS inter area, * - candidate default, U - per-user static route ,. o - ODR,. P - periodic downloaded static route, + - replicated route. Gateway of last resort is not set. 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C. 10.0.0.0/8 is directly connected, Ethernet0/0. L. 10.0.0.1/32 is directly connected, Ethernet0/0. (Note:- above output is called routing table of the router. In this table router keeps the entries of networks know to him, We can see ―C‖ as legend before network entry of 10.0.0.0/8 it shows that it is directly connected on Ethernet 0/0, ―L‖ entry shows the local ip address of the network 10.0.0.0/8, which we assigned to the interface int this task.) Task 10 Check the current configuration of the router with “show running-config” command” and save the configuration. Verification: R1#show running-config Building configuration... Current configuration : 1161 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R1 ! boot-start-marker boot-end-marker ! !.

(12) no aaa new-model clock timezone IST 5 30 mmi polling-interval 60 no mmi auto-configure no mmi pvc mmi snmp-timeout 180 ip source-route ! ! ! ! ip cef no ipv6 traffic interface-statistics no ipv6 cef ! multilink bundle-name authenticated ! ! ! redundancy ! ! ! interface Ethernet0/0 ip address 10.0.0.1 255.0.0.0 ! interface Ethernet0/1 no ip address shutdown ! interface Ethernet0/2 no ip address shutdown ! interface Ethernet0/3 no ip address shutdown ! interface Serial1/0 no ip address shutdown serial restart-delay 0 ! interface Serial1/1.

(13) no ip address shutdown serial restart-delay 0 ! interface Serial1/2 no ip address shutdown serial restart-delay 0 ! interface Serial1/3 no ip address shutdown serial restart-delay 0 ! ip forward-protocol nd ! ! no ip http server no ip http secure-server ! ! control-plane ! ! line con 0 logging synchronous line aux 0 line vty 0 4 login ! exception data-corruption buffer truncate end R1# R1#write Building configuration... [OK] R1#. Task 11 Erase All the Devices and Reload Solution: R1#write erase Erasing the nvram filesystem will remove all configuration files! Continue? [confirm].

(14) [OK] Erase of nvram: complete R1# *Jul. 1 01:09:36.006: %SYS-7-NV_BLOCK_INIT: Initialized the geometry of nvram. R1#reload Proceed with reload? [confirm]. *Jul 1 01:09:39.958: %SYS-5-RELOAD: Reload requested Reason: Reload Command.. by console. Reload. R2#write erase Erasing the nvram filesystem will remove all configuration files! Continue? [confirm] [OK] Erase of nvram: complete R2# *Jul. 1 01:09:36.006: %SYS-7-NV_BLOCK_INIT: Initialized the geometry of nvram. R2#reload Proceed with reload? [confirm]. *Jul 1 01:09:39.958: %SYS-5-RELOAD: Reload requested Reason: Reload Command. ...<output omitted>. by console. Reload.

(15) IP Routing Need of Routing:Routing is the process of moving data from one network to another by forwarding packets via gateways. With IP based networks, the routing decision is based on the destination address in the IP packet's header. Routing is the process of moving a packet of data from one network to another network based on the destination IP address. The Internet uses routing to move data from your computer, across several networks, to reach a final destination, like a website. Specialized computer devices that perform this routing function are referred to as routers. Routers use the information contained in a route to make decisions about which network interface to forward a packet through in order to reach the destination address in the packet. Routers maintain a list of routes which is often referred to as a routing table. Routers look up routes in the routing table to figure out how to move data from one network to another network. Routes are simply the signposts that tell a router which network interface to forward a packet through in order to reach the packet's intended destination Types of Routing There are two basic kinds of routes: static or dynamic. 1. Static Routes Routes can be entered into a router by a person who administrates the network (the network administrator). Since these routes are entered by the administrator, and these routes don't change until the administrator changes them, they are referred to as static routes. 2. Default Routes A default route is also referred to as the 'route of last resort'. This is the route a router uses when all other routes have been examined and none seem to be the right route to use. 3.Dynamic Routes If the routes are learned on-the-fly from other routers, it is called a dynamically-learned route, or a dynamic route for short. Dynamic routes are learned from routing protocols. 4.Routing Protocol A routing protocol is a standardized process by which routers learn and communicate connectivity information, called routes, each of which which describes how to reach a destination host and network. Routers that wish to exchange routing information must use the same routing protocol to communicate routing information..

(16) Routing is the process of learning all the paths through the network (routes) and using routes to forward data from one network to another. A protocol is a standardized way to perform a task. So, a routing protocol would be a standardized way of learning routes and moving data from one network to another. Routing protocols are used by routers to dynamically learn all paths through a set of networks and forward data between the networks. Routers are specialized computer devices designed to perform routing. 5.Examples of Routing Protocols     . EIGRP OSPF RIP, RIP II IS-IS BGP.

(17) Static Routing Configuration. Task 1 Assign Hostnames to Router1, Router2, Router3 R1, R2, R3 respectively. Solution: On Router1 : Router>enable Router#config Router#configure terminal Router(config)#hostname R1 R1(config)#. On Router2 : Router>enable Router#config Router#configure terminal Router(config)#hostname R2 R2(config)#. On Router3 : Router>enable.

(18) Router#config Router#configure terminal Router(config)#hostname R3 R3(config)#. Task 2 Assign IP address 12.0.0.1 and subnet mask of 255.0.0.0 to interface Serial 1/0 and IP address 10.0.0.1 255.0.0.0 to interface Ethernet0/0 on R1. After you complete your configuration verify it. Solution: On R1 : R1(config)#interface serial 1/0 R1(config-if)#ip address 12.0.0.1 255.0.0.0 R1(config-if)#no shutdown R1(config-if)#exit R1(config-if)#int ethernet0/0 R1(config-if)#ip address 10.0.0.1 255.0.0.0 R1(config-if)#no shutdown R1(config-if)#exit R1(config)#exit Verification : R1#show ip interface brief Interface. IP-Address. OK? Method Status. Ethernet0/0. 10.0.0.1. YES manual up. Ethernet0/1. unassigned. YES unset. administratively down down. Ethernet0/2. unassigned. YES unset. administratively down down. Ethernet0/3. unassigned. YES unset. administratively down down. Serial1/0. 12.0.0.1. YES manual up. Serial1/1. unassigned. YES unset. administratively down down. Serial1/2. unassigned. YES unset. administratively down down. Serial1/3. unassigned. YES unset. administratively down down. Task 3 Similarly assign ip address to R2 and R3 as per the diagram.. Protocol up. up.

(19) Solution: On R2 : R2(config)#interface serial 1/0 R2(config-if)#ip address 12.0.0.2 255.0.0.0 R2(config-if)#clock rate 64000 R2(config-if)#no shutdown R2(config-if)#exit R2(config)#interface serial 1/1 R2(config-if)#ip address 23.0.0.2 255.0.0.0 R2(config-if)#clock rate 64000 R2(config-if)#no shutdown R2(config)#interface ethernet 0/0 R2(config-if)#ip address 20.0.0.2 255.0.0.0 R2(config-if)#no shutdown R2(config-if)#exit R2(config)#exit R2# Verification: R2#show ip int brief Interface. IP-Address. OK? Method Status. Protocol. Ethernet0/0. 20.0.0.2. YES manual up. up. Ethernet0/1. unassigned. YES unset. administratively down down. Ethernet0/2. unassigned. YES unset. administratively down down. Ethernet0/3. unassigned. YES unset. administratively down down. Serial1/0. 12.0.0.2. YES manual up. up. Serial1/1. 23.0.0.2. YES manual up. up. Serial1/2. unassigned. YES unset. administratively down down. Serial1/3. unassigned. YES unset. administratively down down. On R3 : R3(config)#interface serial 1/0 R3(config-if)#ip address 23.0.0.3 255.0.0.0.

(20) R3(config-if)#no shutdown R3(config-if)#exit R3(config)#interface ethernet 0/0 R3(config-if)#ip address 30.0.0.3 255.0.0.0 R3(config-if)#no shutdown R3(config-if)#exit R3(config)#exit R3#. Task 4 Check Connectivity Between Directly Connected Interfaces. Verification: On R1: R1#ping 12.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 12.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms. On R2 : R2# R2#ping 12.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 12.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/9/12 ms R2#ping 23.0.0.3. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 23.0.0.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms R2#. On R3 :.

(21) R3# R3#ping 23.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 23.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms R3#. Task 5 Save your configuration Solution: On R1: R1#write On R2: R2#write On R3: R3#write. Task 6 Configure a static route from R1 so that it can reach networks 23.0.0.0/8, 20.0.0.0/8 30.0.0.0/8 Solution: On R1: R1# R1#config terminal R1(config)#ip route 20.0.0.0 255.0.0.0 12.0.0.2 R1(config)#ip route 23.0.0.0 255.0.0.0 12.0.0.2 R1(config)#ip route 30.0.0.0 255.0.0.0 12.0.0.2 Verification: R1# R1#show ip route Codes: L – local, C – connected, S – static, R – RIP, M – mobile, B – BGP, D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area, N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2 E1 – OSPF external type 1,.

(22) E2 – OSPF external type 2, i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area * - candidate default, U – per-user static route. o – ODR,. P – periodic downloaded static route, + - replicated route. Gateway of last resort is not set. 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C. 10.0.0.0/8 is directly connected, Ethernet0/0. L. 10.0.0.1/32 is directly connected, Ethernet0/0 12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 12.0.0.0/8 is directly connected, Serial1/0. L. 12.0.0.1/32 is directly connected, Serial1/0. S. 20.0.0.0/8 [1/0] via 12.0.0.2. S. 23.0.0.0/8 [1/0] via 12.0.0.2. S. 30.0.0.0/8 [1/0] via 12.0.0.2. R1#. Task 7 Configure R2 so that it gets reach ability to networks 10.0.0.0/8, and 30.0.0.0/8 do not specify next hop address to achieve this task On R2 : R2# R2#configure terminal R2(config)#ip route 10.0.0.0 255.0.0.0 serial 1/0 R2(config)#ip route 30.0.0.0 255.0.0.0 serial 1/1 R2(config)#exit R2# Verification: R2# R2#show ip route Codes: L – local, C – connected, S – static, R – RIP, M – mobile, B – BGP, D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area, N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2, E1 – OSPF external type 1, E2 – OSPF external type 2, i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2,. ia – IS-IS inter area,.

(23) * - candidate default, U – per-user static route o – ODR, P – periodic downloaded static route, + - replicated route. Gateway of last resort is not set. S. 10.0.0.0/8 is directly connected, Serial1/0 12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 12.0.0.0/8 is directly connected, Serial1/0. L. 12.0.0.2/32 is directly connected, Serial1/0 20.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 20.0.0.0/8 is directly connected, Ethernet0/0. L. 20.0.0.2/32 is directly connected, Ethernet0/0 23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 23.0.0.0/8 is directly connected, Serial1/1. L. 23.0.0.2/32 is directly connected, Serial1/1. S. 30.0.0.0/8 is directly connected, Serial1/1. R2#. Task 8: Configure R3 in such a manner that it gets rechability to all other networks in single static route. Do not configure any more specific static routes to achieve this task. On R3 : R3# R3#configure terminal R3(config)#ip route 0.0.0.0 0.0.0.0 23.0.0.2 R3(config)#exit R3#. Verification : R3# R3#show ip route Codes: L – local, C – connected, S – static, R – RIP, M – mobile,.

(24) B – BGP,. D – EIGRP, EX – EIGRP external, O – OSPF,. IA – OSPF inter area. N1 – OSPF NSSA external type 1,. N2 – OSPF NSSA external type 2 E1 – OSPF external type 1, E2 – OSPF external type 2 i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2 ia – IS-IS inter area, * - candidate default, U – per-user static route o – ODR, P – periodic downloaded static route, + - replicated route. Gateway of last resort is 23.0.0.2 to network 0.0.0.0. S*. 0.0.0.0/0 [1/0] via 23.0.0.2 23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 23.0.0.0/8 is directly connected, Serial1/0. L. 23.0.0.3/32 is directly connected, Serial1/0. R3#. Task 9 : Ping 30.0.0.3 from R1, Ping 10.0.0.1 and 30.0.0.3 for R2 Ping 10.0.0.1 from R3 to test end to end reachability. R1# R1#ping 30.0.0.3. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 30.0.0.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/18/24ms R1# R2# R2#ping 10.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/8 ms R2# R2#ping 30.0.0.3. Type escape sequence to abort..

(25) Sending 5, 100-byte ICMP Echos to 30.0.0.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/37/80 ms R2# R3# R3#ping 10.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms R3#. Explanation:As we see from above output that we have got the full reachabltiy. On R1 we have give destination network i.e 20.0.0.0,23.0.0.0 and 30.0.0.0 and their respective subnet masks and in the last part we gave the next hop address that is router to whom packet should be routed. Here the ip route format is ―ip route <dest net> <dest subnet> <next hop address> ip route 20.0.0.0 255.0.0.0 12.0.0.2 ip route 23.0.0.0 255.0.0.0 12.0.0.2 ip route 30.0.0.0 255.0.0.0 12.0.0.2 on R2 we have been instructed not to give next hop address so we can here give outgoing interface ip route 10.0.0.0 255.0.0.0 serial1/0 ip route 30.0.0.0 255.0.0.0 serial1/1 On R3 we have instructed not to use any specific routes so here we are using special static route which is also called as default route. That is if router does not get any specific network in his routing table. It is going to use the default route to route the packet..

(26) ip route 0.0.0.0 0.0.0.0 23.0.0.2. RIPv2. RIPv2 was first described in RFC 1388 and RFC 1723 (1994); the current RFC is 2453, written in November 1998. Although current environments use advanced routing protocols such as OSPF and EIGRP, there still are networks using RIP. The need to use VLSMs and other requirements prompted the definition of RIPv2. RIPv2 improves upon RIPv1 with the ability to use VLSM, with support for route authentication, and with multicasting of route updates. RIPv2 supports CIDR. It still sends updates every 30 seconds and retains the 15-hop limit; it also uses triggered updates. RIPv2 still uses UDP port 520; the RIP process is responsible for checking the version number. It retains the loop-prevention strategies of poison reverse and counting to infinity. On Cisco routers, RIPv2 has the same administrative distance as RIPv1, which is 120. Finally, RIPv2 uses the IP address 224.0.0.9 when multicasting route updates to other RIP routers. As in RIPv1, RIPv2 will, by default, summarize IP networks at network boundaries. You can disable auto-summarization if required. You can use RIPv2 in small networks where VLSM is required. It also works at the edge of larger networks. RIPv2 Forwarding Information Base RIPv2 maintains a routing table database as in Version 1. The difference is that it also keeps the subnet mask information. The following list repeats the table information of RIPv1:.

(27)     . IP address—IP address of the destination host or network, with subnet mask Gateway—The first gateway along the path to the destination Interface—The physical network that must be used to reach the destination Metric—A number indicating the number of hops to the destination Timer—The amount of time since the route entry was last updated RIPv2 Design Things to remember in designing a network with RIPv2 include that it supports VLSM within networks and CIDR for network summarization across adjacent networks. RIPv2 allows for the summarization of routes in a hierarchical network. RIPv2 is still limited to 16 hops; therefore, the network diameter cannot exceed this limit. RIPv2 multicasts its routing table every 30 seconds to the multicast IP address 224.0.0.9. RIPv2 is usually limited to accessing networks where it can interoperate with servers running routed or with non-Cisco routers. RIPv2 also appears at the edge of larger internetworks. RIPv2 further provides for route authentication.. Split Horizon: In this example, network node A routes packets to node B in order to reach node C. The links between the nodes are distinct point-to-point links.. According to the split-horizon rule, node A does not advertise its route for C (namely A to B to C) back to B. On the surface, this seems redundant since B will never route via node A because the route costs more than the direct route from B to C. However, if the link between B and C goes down, and B had received a route from A, B could end up using that route via A. A would send the packet right back to B, creating a loop. With the split-horizon rule in place, this particular loop scenario cannot happen, improving convergence time in complex, highly-redundant environments Poison Reverse: Split-horizon routing with poison reverse is a variant of split-horizon route advertising in which a router actively advertises routes as unreachable over the interface over which they were learned. The effect of such an announcement is to immediately remove most looping routes before they can propagate through the network. The main disadvantage of poison reverse is that it can significantly increase the size of routing announcements in certain fairly common network topologies. RIPv2 Summary The characteristics of RIPv2 follow:   . Distance-vector protocol. Uses UDP port 520. Classless protocol (support for CIDR)..

(28)           . Supports VLSMs. Metric is router hop count. Maximum hop count is 15; infinite (unreachable) routes have a metric of 16. Periodic route updates sent every 30 seconds to multicast address 224.0.0.9. 25 routes per RIP message (24 if you use authentication). Supports authentication. Implements split horizon with poison reverse. Implements triggered updates. Subnet mask included in route entry. Administrative distance for RIPv2 is 120. Used in small, flat networks or at the edge of larger networks.. RIP Configuration Load IP Routing initials prior to starting. Task 1 Configure RIPv2 on R1 advertise it’s all network into RIP Solution: On R1: R1# R1#configure terminal R1(config)#router rip R1(config-router)#version 2 R1(config-router)#network 10.0.0.0.

(29) R1(config-router)#network 12.0.0.0 R1(config-router)#exit R1(config)#exit R1#. Verification: On R1: R1# R1#show ip protocols *** IP Routing is NSF aware ***. Routing Protocol is "rip" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Sending updates every 30 seconds, next due in 27 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Redistributing: rip Default version control: send version 2, receive version 2 Interface. Send. Recv. Ethernet0/0. 2. 2. Serial1/0. 2. 2. Triggered RIP. Key-chain. Automatic network summarization is in effect Maximum path: 4 Routing for Networks: 10.0.0.0 12.0.0.0 Routing Information Sources: Gateway. Distance. Last Update. Distance: (default is 120). R1#. Task 2 From above output we can see that R1 is doing auto-summarization so disable autosummarization on R1.

(30) Solution: On R1: R1# R1#configure terminal R1(config)#router rip R1(config-router)#no auto-summary R1(config-router)#exit R1(config)#exit R1# Verification: R1# R1#show ip protocols *** IP Routing is NSF aware ***. Routing Protocol is "rip" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Sending updates every 30 seconds, next due in 0 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Redistributing: rip Default version control: send version 2, receive version 2 Interface. Send. Recv. Ethernet0/0. 2. 2. Serial1/0. 2. 2. Triggered RIP. Key-chain. Automatic network summarization is not in effect Maximum path: 4 Routing for Networks: 10.0.0.0 12.0.0.0 Routing Information Sources: Gateway. Distance. Last Update. Distance: (default is 120) R1#. Task 3 configure RIP v2 on R2 and R3 advertise all the networks and disable autosummarization..

(31) Solution: On R2: R2# R2#config terminal R2(config)#router rip R2(config-router)#version 2 R2(config-router)#no auto-summary R2(config-router)#network 12.0.0.0 R2(config-router)#network 23.0.0.0 R2(config-router)#network 20.0.0.0 R2(config-router)#exit R2(config)#exit R2#. On R3: R3# R3#configure terminal R3(config)#router rip R3(config-router)#no auto-summary R3(config-router)#version 2 R3(config-router)#network 23.0.0.0 R3(config-router)#network 30.0.0.0 R3(config-router)#exit R3(config)#exit R3#. Task 4 Verify Routing tables of all 3 routers and test end-to-end connectivity. Verification: R1#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B – BGP. D - EIGRP, EX - EIGRP external, O - OSPF,. IA - OSPF inter area. N1 - OSPF NSSA external type 1,.

(32) N2 - OSPF NSSA external type 2, E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2. ia - IS-IS inter area,. * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route. Gateway of last resort is not set. 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C. 10.0.0.0/24 is directly connected, Ethernet0/0. L. 10.0.0.1/32 is directly connected, Ethernet0/0 12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 12.0.0.0/24 is directly connected, Serial1/0. L. 12.0.0.1/32 is directly connected, Serial1/0 20.0.0.0/24 is subnetted, 1 subnets. R. 20.0.0.0 [120/1] via 12.0.0.2, 00:00:24, Serial1/0 23.0.0.0/24 is subnetted, 1 subnets. R. 23.0.0.0 [120/1] via 12.0.0.2, 00:00:24, Serial1/0 30.0.0.0/24 is subnetted, 1 subnets. R. 30.0.0.0 [120/2] via 12.0.0.2, 00:00:24, Serial1/0. R1#. R1#ping 23.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 23.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/10/16 ms R1#ping 20.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 20.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/8 ms R1#ping 30.0.0.3. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 30.0.0.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 12/16/20 ms.

(33) R1#. On R2: R2# R2#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B -. BGP, D - EIGRP, EX - EIGRP external, O - OSPF,. IA - OSPF inter area , N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 , ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route. Gateway of last resort is not set. 10.0.0.0/24 is subnetted, 1 subnets R. 10.0.0.0 [120/1] via 12.0.0.1, 00:00:14, Serial1/0 12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 12.0.0.0/24 is directly connected, Serial1/0. L. 12.0.0.2/32 is directly connected, Serial1/0 20.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 20.0.0.0/24 is directly connected, Ethernet0/0. L. 20.0.0.2/32 is directly connected, Ethernet0/0 23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 23.0.0.0/24 is directly connected, Serial1/1. L. 23.0.0.2/32 is directly connected, Serial1/1 30.0.0.0/24 is subnetted, 1 subnets. R. 30.0.0.0 [120/1] via 23.0.0.3, 00:00:27, Serial1/1. R2# R2# R2#ping 10.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms R2#ping 30.0.0.3.

(34) Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 30.0.0.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms R2#. On R3: R3# R3#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B – BGP, D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area, N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2, E1 - OSPF external type 1, E2 - OSPF external type 2,. i - IS-IS, su - IS-IS summary,. L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area , * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route. Gateway of last resort is not set. 10.0.0.0/24 is subnetted, 1 subnets R. 10.0.0.0 [120/2] via 23.0.0.2, 00:00:06, Serial1/0 12.0.0.0/24 is subnetted, 1 subnets. R. 12.0.0.0 [120/1] via 23.0.0.2, 00:00:06, Serial1/0 20.0.0.0/24 is subnetted, 1 subnets. R. 20.0.0.0 [120/1] via 23.0.0.2, 00:00:06, Serial1/0 23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 23.0.0.0/24 is directly connected, Serial1/0. L. 23.0.0.3/32 is directly connected, Serial1/0 30.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 30.0.0.0/24 is directly connected, Ethernet0/0. L. 30.0.0.3/32 is directly connected, Ethernet0/0. R3# R3# R3#ping 12.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 12.0.0.1, timeout is 2 seconds: !!!!!.

(35) Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms R3#ping 20.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 20.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/8/12 ms R3#ping 10.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms R3#. Task 5 Configure all three routers in such way that they send updates through only required interfaces Solution: On R1: R1#config terminal R1(config)#router rip R1(config-router)#passive-interface ethernet 0/0 R1(config-router)#exit R1(config)#exit R1#. On R2: R2#config terminal R2(config)#router rip R2(config-router)#passive-interface ethernet 0/0 R2(config-router)#exit R2(config)#exit R2#. On R3:.

(36) R3#config terminal R3(config)#router rip R3(config-router)#passive-interface ethernet 0/0 R3(config-router)#exit R3(config)#exit R3 Verification: R1# R1#show ip protocols *** IP Routing is NSF aware ***. Routing Protocol is "rip" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Sending updates every 30 seconds, next due in 2 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Redistributing: rip Default version control: send version 2, receive version 2 Interface. Send. Recv. Serial1/0. 2. 2. Triggered RIP. Key-chain. Automatic network summarization is not in effect Maximum path: 4 Routing for Networks: 10.0.0.0 12.0.0.0 Passive Interface(s): Ethernet0/0 Routing Information Sources: Gateway 12.0.0.2. Distance 120. Last Update 00:00:01. Distance: (default is 120). Explanation: Task 1 is asking us to configure RIP version 2 on all the interfaces. In the router rip sub configuration we have to advertise our interfaces with network command. We can only declare networks in their classfull boundaries. Version 2 is to be specified as default behavior is send version 1 updates and receive both version 1 and version 2 updates. This configuration can be checked in show ip protocols.

(37) In configuration of task 2 we can see that by default RIP will always do auto-summarization. To disable the auto-summarization we can give no auto-summary under RIP routing process. Task 5 is asking us to send RIPv2 updates only out of required interface. Always remember that RIPv2 does support classless network advertisement but we can only publish classfull networks in RIPv2. By default all the routing protocols except BGP, Send hello packets and advertise the networks, which we have defined by network command. In RIPv2 if we make a passive interface then that interface is advertised but it does not send any updates. But the limitation in RIPv2 is this interface can still receive RIP updates.. EIGRP Implementing EIGRP EIGRP is an advanced distance vector routing protocol developed by Cisco. EIGRP is suited for many different topologies and media. In a well-designed network, EIGRP scales well and provides extremely quick convergence times with minimal overhead. EIGRP is a popular choice for a routing protocol on Cisco devices. Introducing EIGRP EIGRP is a Cisco-proprietary routing protocol that combines the advantages of link-state and distance vector routing protocols. EIGRP is an advanced distance vector or hybrid routing protocol that includes the following features: . Rapid Convergence.

(38) EIGRP uses the Diffusing Update Algorithm (DUAL) to achieve rapid convergence. A router that uses EIGRP stores all available backup routes for destinations so that it can quickly adapt to alternate routes. If no appropriate route or backup route exists in the local routing table, EIGRP queries its neighbors to discover an alternate route. . Reduced bandwidth usage EIGRP does not make periodic updates. Instead, it sends partial updates when the path or the metric changes for that route. When path information changes, DUAL sends an update about only that link rather than about the entire table.. . Multiple network layer support EIGRP supports AppleTalk, IP version 4 (IPv4), IP version 6 (IPv6), and Novell Internetwork Packet Exchange (IPX), which use protocol-dependent modules (PDM). PDMs are responsible for protocol requirements that are specific to the network layer.. . Classless routing Because EIGRP is a classless routing protocol, it advertises a routing mask for each destination network. The routing mask feature enables EIGRP to support discontiguous subnetworks and variable-length subnet masks (VLSM).. . Less overhead EIGRP uses multicast and unicast rather than broadcast. As a result, end stations are unaffected by routing updates and requests for topology information.. . Load balancing EIGRP supports unequal metric load balancing, which allows administrators to better distribute traffic flow in their networks.. . Easy summarization EIGRP enables administrators to create summary routes anywhere within the network rather than rely on the traditional distance vector approach of performing classful route summarization only at major network boundaries. Each EIGRP router maintains a neighbor table. This table includes a list of directly connected EIGRP routers that have an adjacency with this router. Each EIGRP router maintains a topology table for each routed protocol configuration. The topology table includes route entries for every destination that the router learns. EIGRP chooses the best routes to a destination from the topology table and places these routes in the routing table. In EIGRP, the best route is called a successor route while a backup route is called the feasible successor. To determine the best route (successor) and the backup route (feasible successor) to a destination, EIGRP uses the following two parameters:. . Advertised distance The EIGRP metric for an EIGRP neighbor to reach a particular network.

(39) . Feasible distance The advertised distance for a particular network learned from an EIGRP neighbor plus the EIGRP metric to reach that neighbor A router compares all feasible distances to reach a specific network and then selects the lowest feasible distance and places it in the routing table. The feasible distance for the chosen route becomes the EIGRP routing metric to reach that network in the routing table. The EIGRP topology database contains all the routes that are known to each EIGRP neighbor. Routers A and B send their routing tables to Router C, whose table is displayed in Both Routers A and B have pathways to network 10.1.1.0/24, as well as to other networks that are not shown. .. Configuring and Verifying EIGRP Use the router eigrp and network commands to create an EIGRP routing process. Note that EIGRP requires an autonomous system (AS) number. The AS number does not have to be registered as is the case when routing on the Internet with the Border Gateway Protocol (BGP) routing protocol. However, all routers within an AS must use the same AS number to exchange routing information with each other.. The network command defines a major network number to which the router is directly connected. The EIGRP routing process looks for interfaces that have an IP address that belongs to the networks that are specified with the network command and begins the EIGRP process on these interfaces..

(40) EIGRP Command Example Command router eigrp 100 network 172.16.0.0 network 10.0.0.0. Description Enables the EIGRP routing process for AS 100 Associates network 172.16.0.0 with the EIGRP routing process Associates network 10.0.0.0 with the EIGRP routing process. EIGRP sends updates out of the interfaces in networks 10.0.0.0 and 172.16.0.0. The updates include information about networks 10.0.0.0 and 172.16.0.0 and any other networks that EIGRP learns. EIGRP automatically summarizes routes at the classful boundary. In some cases, you might not want automatic summarization to occur. For example, if you have discontiguous networks, you need to disable automatic summarization to minimize router confusion. To disable automatic summarization, use the no auto-summary command in the EIGRP router configuration mode. The show ip protocols command displays the parameters and current state of the active routing protocol process. This command shows the EIGRP AS number. It also displays filtering and redistribution numbers and neighbor and distance information. This also shows the networks that are currently being advertised on the router by the protocol. Use the show ip eigrp interfaces [type number] [as-number] command to determine on which interfaces EIGRP is active, and to learn information about EIGRP that relates to those interfaces. If you specify an interface by using the type number option, only that interface is displayed. Otherwise, all interfaces on which EIGRP is running are displayed. If you specify an AS using the as-number option, only the routing process for the specified AS is displayed. Otherwise, all EIGRP processes are displayed. Exam shows the output of the show ip eigrp interfaces command. EIGRP Summary The characteristics of EIGRP follow:           . Hybrid routing protocol (distance vector that has link-state protocol characteristics). Uses IP protocol 88. Classless protocol (supports VLSMs). Default composite metric uses bandwidth and delay. You can factor load and reliability into the metric. Sends partial route updates only when there are changes. Support for authentication. Uses DUAL for loop prevention. By default, equal-cost load balancing. Unequal-cost load balancing with the variance command. Administrative distance is 90 for EIGRP internal routes, 170 for EIGRP external routes, and 5 for EIGRP summary routes. Potential routing protocol for the core of a network; used in large networks..

(41) EIGRP Configuration Load IP Routing Initials Prior to Starting. Task 1 Configure EIGRP AS 100 on R1 advertise it’s all networks into EIGRP Solution: On R1 : R1# R1#configure terminal.

(42) R1(config)#router eigrp 100 R1(config-router)#network 10.0.0.0 R1(config-router)#network 12.0.0.0 R1(config-router)#exit R1(config)#exit R1#. Verification: On R1: R1# *** IP Routing is NSF aware ***. Routing Protocol is "eigrp 100" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates Redistributing: eigrp 100 EIGRP-IPv4 Protocol for AS(100) Metric weight K1=1, K2=0, K3=1, K4=0, K5=0 NSF-aware route hold timer is 240 Router-ID: 12.0.0.1 Topology : 0 (base) Active Timer: 3 min Distance: internal 90 external 170 Maximum path: 4 Maximum hopcount 100 Maximum metric variance 1. Automatic Summarization: enabled Maximum path: 4 Routing for Networks: 10.0.0.0 12.0.0.0.

(43) Routing Information Sources: Gateway. Distance. Last Update. Distance: internal 90 external 170. R1#. Task 2 From above output we can see that R1 is doing auto-summarization so disable autosummarization on R1 Solution: On R1: R1# R1#configure terminal R1(config)#router eigrp 100 R1(config-router)#no auto-summary R1(config-router)#exit R1(config)#exit R1# Verification: R1# R1#show ip protocols *** IP Routing is NSF aware ***. Routing Protocol is "eigrp 100" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates Redistributing: eigrp 100 EIGRP-IPv4 Protocol for AS(100) Metric weight K1=1, K2=0, K3=1, K4=0, K5=0 NSF-aware route hold timer is 240 Router-ID: 12.0.0.1 Topology : 0 (base).

(44) Active Timer: 3 min Distance: internal 90 external 170 Maximum path: 4 Maximum hopcount 100 Maximum metric variance 1. Automatic Summarization: disabled Maximum path: 4 Routing for Networks: 10.0.0.0 12.0.0.0 Routing Information Sources: Gateway. Distance. Last Update. Distance: internal 90 external 170. R1#. Task 4 configure EIGRP AS 100 on R2 and R3 advertise all the networks and disable autosummarization. Solution: On R2: R2# R2#config terminal R2(config)#router eigrp 100 R2(config-router)#no auto-summary R2(config-router)#network 12.0.0.0 R2(config-router)#network 23.0.0.0 R2(config-router)#network 20.0.0.0 R2(config-router)#exit R2(config)#exit R2#. On R3: R3# R3#configure terminal.

(45) R3(config)#router eigrp 100 R3(config-router)#no auto-summary R3(config-router)#network 23.0.0.0 R3(config-router)#network 30.0.0.0 R3(config-router)#exit R3(config)#exit R3#. Task 5 Verify Routing tables of all 3 routers and test end-to-end connectivity. Verification: On R1: R1#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B – BGP. D - EIGRP, EX - EIGRP external, O - OSPF,. IA - OSPF inter area. N1 - OSPF NSSA external type 1,. N2 - OSPF NSSA external type 2, E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2. ia - IS-IS inter area,. * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route. Gateway of last resort is not set. 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks D. 10.0.0.0/24 is directly connected, Ethernet0/0. L. 10.0.0.1/32 is directly connected, Ethernet0/0 12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 12.0.0.0/24 is directly connected, Serial1/0. L. 12.0.0.1/32 is directly connected, Serial1/0 20.0.0.0/24 is subnetted, 1 subnets. D. 20.0.0.0 [120/1] via 12.0.0.2, 00:00:24, Serial1/0 23.0.0.0/24 is subnetted, 1 subnets. D. 23.0.0.0 [120/1] via 12.0.0.2, 00:00:24, Serial1/0 30.0.0.0/24 is subnetted, 1 subnets. D R1#. 30.0.0.0 [120/2] via 12.0.0.2, 00:00:24, Serial1/0.

(46) R1# R1#ping 23.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 23.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/10/16 ms R1#ping 20.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 20.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/8 ms R1#ping 30.0.0.3. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 30.0.0.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 12/16/20 ms. R1#. On R2: R2# R2#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B -. BGP, D - EIGRP, EX - EIGRP external, O - OSPF,. IA - OSPF inter area , N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 , ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route. Gateway of last resort is not set. 10.0.0.0/24 is subnetted, 1 subnets D. 10.0.0.0 [120/1] via 12.0.0.1, 00:00:14, Serial1/0.

(47) 12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C. 12.0.0.0/24 is directly connected, Serial1/0. L. 12.0.0.2/32 is directly connected, Serial1/0 20.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 20.0.0.0/24 is directly connected, Ethernet0/0. L. 20.0.0.2/32 is directly connected, Ethernet0/0 23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 23.0.0.0/24 is directly connected, Serial1/1. L. 23.0.0.2/32 is directly connected, Serial1/1 30.0.0.0/24 is subnetted, 1 subnets. D. 30.0.0.0 [120/1] via 23.0.0.3, 00:00:27, Serial1/1. R2# R2# R2#ping 10.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms R2#ping 30.0.0.3. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 30.0.0.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms R2#. On R3: R3# R3#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B – BGP, D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area, N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2, E1 - OSPF external type 1, E2 - OSPF external type 2,. i - IS-IS, su - IS-IS summary,. L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area , * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route. Gateway of last resort is not set.

(48) 10.0.0.0/24 is subnetted, 1 subnets D. 10.0.0.0 [120/2] via 23.0.0.2, 00:00:06, Serial1/0 12.0.0.0/24 is subnetted, 1 subnets. D. 12.0.0.0 [120/1] via 23.0.0.2, 00:00:06, Serial1/0 20.0.0.0/24 is subnetted, 1 subnets. D. 20.0.0.0 [120/1] via 23.0.0.2, 00:00:06, Serial1/0 23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 23.0.0.0/24 is directly connected, Serial1/0. L. 23.0.0.3/32 is directly connected, Serial1/0 30.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 30.0.0.0/24 is directly connected, Ethernet0/0. L. 30.0.0.3/32 is directly connected, Ethernet0/0. R3# R3# R3#ping 12.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 12.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms R3#ping 20.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 20.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/8/12 ms R3#ping 10.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms R3#. Task 5 Configure all three routers in such manner that they send updates through only required interfaces Solution: On R1.

(49) R1#config terminal R1(config)#router eigrp 100 R1(config-router)#passive-interface ethernet 0/0 R1(config-router)#exit R1(config)#exit R1#. On R2: R2#config terminal R2(config)#router eigrp 100 R2(config-router)#passive-interface ethernet 0/0 R2(config-router)#exit R2(config)#exit R2#. On R3: R3#config terminal R3(config)#router eigrp 100 R3(config-router)#passive-interface ethernet 0/0 R3(config-router)#exit R3(config)#exit R3#. Verification: On R1: R1# R1#show ip protocols R1#show ip protocols *** IP Routing is NSF aware ***.

(50) Routing Protocol is "eigrp 100" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates Redistributing: eigrp 100 EIGRP-IPv4 Protocol for AS(100) Metric weight K1=1, K2=0, K3=1, K4=0, K5=0 NSF-aware route hold timer is 240 Router-ID: 12.0.0.1 Topology : 0 (base) Active Timer: 3 min Distance: internal 90 external 170 Maximum path: 4 Maximum hopcount 100 Maximum metric variance 1. Automatic Summarization: disabled Maximum path: 4 Routing for Networks: 10.0.0.0 12.0.0.0 Passive Interface(s): Ethernet0/0 Routing Information Sources: Gateway. Distance. Last Update. Distance: internal 90 external 170. R1#. OSPF Background Information OSPF protocol was developed due to a need in the internet community to introduce a high functionality non-proprietary Internal Gateway Protocol (IGP) for the TCP/IP protocol family. The discussion of the creation of a common interoperable IGP for the Internet started in 1988 and did not get formalized until 1991. At that time the OSPF Working Group requested that OSPF be considered for advancement to Draft Internet Standard. The OSPF protocol is based on link-state technology, which is a departure from the Bellman-Ford vector based algorithms used in traditional Internet routing protocols such as RIP. OSPF has.

(51) introduced new concepts such as authentication of routing updates, Variable Length Subnet Masks (VLSM), route summarization, and so forth. These chapters discuss the OSPF terminology, algorithm and the pros and cons of the protocol in designing the large and complicated networks of today. OSPF versus RIP The rapid growth and expansion of today's networks has pushed RIP to its limits. RIP has certain limitations that can cause problems in large networks:  .  . . . RIP has a limit of 15 hops. A RIP network that spans more than 15 hops (15 routers) is considered unreachable. RIP cannot handle Variable Length Subnet Masks (VLSM). Given the shortage of IP addresses and the flexibility VLSM gives in the efficient assignment of IP addresses, this is considered a major flaw. Periodic broadcasts of the full routing table consume a large amount of bandwidth. This is a major problem with large networks especially on slow links and WAN clouds. RIP converges slower than OSPF. In large networks convergence gets to be in the order of minutes. RIP routers go through a period of a hold-down and garbage collection and slowly time-out information that has not been received recently. This is inappropriate in large environments and could cause routing inconsistencies. RIP has no concept of network delays and link costs. Routing decisions are based on hop counts. The path with the lowest hop count to the destination is always preferred even if the longer path has a better aggregate link bandwidth and less delays. RIP networks are flat networks. There is no concept of areas or boundaries. With the introduction of classless routing and the intelligent use of aggregation and summarization, RIP networks seem to have fallen behind. Some enhancements were introduced in a new version of RIP called RIP2. RIP2 addresses the issues of VLSM, authentication, and multicast routing updates. RIP2 is not a big improvement over RIP (now called RIP 1) because it still has the limitations of hop counts and slow convergence which are essential in today’s large networks. OSPF, on the other hand, addresses most of the issues previously presented:.   .   .  . With OSPF, there is no limitation on the hop count. The intelligent use of VLSM is very useful in IP address allocation. OSPF uses IP multicast to send link-state updates. This ensures less processing on routers that are not listening to OSPF packets. Also, updates are only sent in case routing changes occur instead of periodically. This ensures a better use of bandwidth. OSPF has better convergence than RIP. This is because routing changes are propagated instantaneously and not periodically. OSPF allows for better load balancing. OSPF allows for a logical definition of networks where routers can be divided into areas. This limits the explosion of link state updates over the whole network. This also provides a mechanism for aggregating routes and cutting down on the unnecessary propagation of subnet information. OSPF allows for routing authentication by using different methods of password authentication. OSPF allows for the transfer and tagging of external routes injected into an Autonomous System. This keeps track of external routes injected by exterior protocols such as BGP. This of course leads to more complexity in the configuration and troubleshooting of OSPF networks. Administrators that are used to the simplicity of RIP are challenged with the amount of new information they have to learn in order to keep up with OSPF networks. Also, this introduces more overhead in memory allocation and CPU utilization. Some of the routers running RIP might have to be upgraded in order to handle the overhead caused by OSPF..

(52) What Do We Mean by Link-States? OSPF is a link-state protocol. We could think of a link as being an interface on the router. The state of the link is a description of that interface and of its relationship to its neighboring routers. A description of the interface would include, for example, the IP address of the interface, the mask, the type of network it is connected to, the routers connected to that network and so on. The collection of all these link-states would form a link-state database. Shortest Path First Algorithm OSPF uses a shorted path first algorithm in order to build and calculate the shortest path to all known destinations. The shortest path is calculated with the use of the Dijkstra algorithm. The algorithm by itself is quite complicated. This is a very high level, simplified way of looking at the various steps of the algorithm: 1. Upon initialization or due to any change in routing information, a router generates a link-state advertisement. This advertisement represents the collection of all link-states on that router. 2. All routers exchange link-states by means of flooding. Each router that receives a link-state update should store a copy in its link-state database and then propagate the update to other routers. 3. After the database of each router is completed, the router calculates a Shortest Path Tree to all destinations. The router uses the Dijkstra algorithm in order to calculate the shortest path tree. The destinations, the associated cost and the next hop to reach those destinations form the IP routing table. 4. In case no changes in the OSPF network occur, such as cost of a link or a network being added or deleted, OSPF should be very quiet. Any changes that occur are communicated through link-state packets, and the Dijkstra algorithm is recalculated in order to find the shortest path. The algorithm places each router at the root of a tree and calculates the shortest path to each destination based on the cumulative cost required to reach that destination. Each router will have its own view of the topology even though all the routers will build a shortest path tree using the same link-state database. The following sections indicate what is involved in building a shortest path tree.. OSPF Cost The cost (also called metric) of an interface in OSPF is an indication of the overhead required to send packets across a certain interface. The cost of an interface is inversely proportional to the bandwidth of that interface. A higher bandwidth indicates a lower cost. There is more overhead (higher cost) and time delays involved in crossing a 56k serial line than crossing a 10M Ethernet line. The formula used to calculate the cost is: Cost = 100/Bandwidth in Mbps.

(53) OSPF Configuration Load IP Routing Intials Prior to Starting. Task 1 Configure OSPF area 0 on R1 advertise it’s all networks into OSPF use process id 100 Solution: On R1:.

(54) R1# R1#configure terminal R1(config)#router ospf 100 R1(config-router)#network 10.0.0.0 0.0.0.255 area 0 R1(config-router)#network 12.0.0.0 0.0.0.255 area 0 R1(config-router)#exit R1(config)#exit R1#. Verification: On R1: R1# R1#show ip protocols *** IP Routing is NSF aware ***. Routing Protocol is "ospf 100" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 12.0.0.1 Number of areas in this router is 1. 1 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: 10.0.0.0 0.0.0.255 area 0 12.0.0.0 0.0.0.255 area 0 Routing Information Sources: Gateway. Distance. Last Update. Distance: (default is 110). R1#. Task 2 configure OSPF area 0 on R2 and R3 advertise all the networks use process id 100 Solution:.

(55) On R2:. R2# R2#config terminal R2(config)#router ospf 100 R2(config-router)#network 12.0.0.0 0.0.0.255 area 0 R2(config-router)#network 23.0.0.0 0.0.0.255 area 0 R2(config-router)#network 20.0.0.0 0.0.0.255 area 0 R2(config-router)#exit R2(config)#exit R2#. On R3: R3# R3#configure terminal R3(config)#router ospf 100 R3(config-router)#network 23.0.0.0 0.0.0.255 area 0 R3(config-router)#network 30.0.0.0 0.0.0.255 area 0 R3(config-router)#exit R3(config)#exit R3#. Task 3 Verify Routing tables of all 3 routers and test end-to-end connectivity. Verification: R1#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B – BGP. D - EIGRP, EX - EIGRP external, O - OSPF,. IA - OSPF inter area. N1 - OSPF NSSA external type 1,. N2 - OSPF NSSA external type 2, E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2. ia - IS-IS inter area,. * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route.

(56) Gateway of last resort is not set. 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks O. 10.0.0.0/24 is directly connected, Ethernet0/0. L. 10.0.0.1/32 is directly connected, Ethernet0/0 12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 12.0.0.0/24 is directly connected, Serial1/0. L. 12.0.0.1/32 is directly connected, Serial1/0 20.0.0.0/24 is subnetted, 1 subnets. O. 20.0.0.0 [120/1] via 12.0.0.2, 00:00:24, Serial1/0 23.0.0.0/24 is subnetted, 1 subnets. O. 23.0.0.0 [120/1] via 12.0.0.2, 00:00:24, Serial1/0 30.0.0.0/24 is subnetted, 1 subnets. O. 30.0.0.0 [120/2] via 12.0.0.2, 00:00:24, Serial1/0. R1# R1# R1#ping 23.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 23.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/10/16 ms R1#ping 20.0.0.2. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 20.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/8 ms R1#ping 30.0.0.3. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 30.0.0.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 12/16/20 ms. R1#. On R2: R2# R2#show ip route.

(57) Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B -. BGP, D - EIGRP, EX - EIGRP external, O - OSPF,. IA - OSPF inter area , N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 , ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route. Gateway of last resort is not set. 10.0.0.0/24 is subnetted, 1 subnets O. 10.0.0.0 [120/1] via 12.0.0.1, 00:00:14, Serial1/0 12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 12.0.0.0/24 is directly connected, Serial1/0. L. 12.0.0.2/32 is directly connected, Serial1/0 20.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 20.0.0.0/24 is directly connected, Ethernet0/0. L. 20.0.0.2/32 is directly connected, Ethernet0/0 23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 23.0.0.0/24 is directly connected, Serial1/1. L. 23.0.0.2/32 is directly connected, Serial1/1 30.0.0.0/24 is subnetted, 1 subnets. O. 30.0.0.0 [120/1] via 23.0.0.3, 00:00:27, Serial1/1. R2# R2# R2#ping 10.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms R2#ping 30.0.0.3. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 30.0.0.3, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms R2#.

(58) On R3: R3# R3#show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B – BGP, D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area, N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2, E1 - OSPF external type 1, E2 - OSPF external type 2,. i - IS-IS, su - IS-IS summary,. L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area , * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route. Gateway of last resort is not set. 10.0.0.0/24 is subnetted, 1 subnets O. 10.0.0.0 [120/2] via 23.0.0.2, 00:00:06, Serial1/0 12.0.0.0/24 is subnetted, 1 subnets. O. 12.0.0.0 [120/1] via 23.0.0.2, 00:00:06, Serial1/0 20.0.0.0/24 is subnetted, 1 subnets. O. 20.0.0.0 [120/1] via 23.0.0.2, 00:00:06, Serial1/0 23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 23.0.0.0/24 is directly connected, Serial1/0. L. 23.0.0.3/32 is directly connected, Serial1/0 30.0.0.0/8 is variably subnetted, 2 subnets, 2 masks. C. 30.0.0.0/24 is directly connected, Ethernet0/0. L. 30.0.0.3/32 is directly connected, Ethernet0/0. R3# R3# R3#ping 12.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 12.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms R3#ping 20.0.0.2.

(59) Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 20.0.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/8/12 ms R3#ping 10.0.0.1. Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms R3#. Task 4 Configure all three routers in such manner that they send updates through only required interfaces On R1 R1#config terminal R1(config)#router ospf 100 R1(config-router)#passive-interface ethernet 0/0 R1(config-router)#exit R1(config)#exit R1#. On R2: R2#config terminal R2(config)#router ospf 100 R2(config-router)#passive-interface ethernet 0/0 R2(config-router)#exit R2(config)#exit R2#. On R3: R3#config terminal R3(config)#router ospf 100 R3(config-router)#passive-interface ethernet 0/0.

(60) R3(config-router)#exit R3(config)#exit R3# Verification: On R1: R1# R1#show ip protocols *** IP Routing is NSF aware ***. Routing Protocol is "ospf 100" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 12.0.0.1 Number of areas in this router is 1. 1 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: 10.0.0.0 0.0.0.255 area 0 12.0.0.0 0.0.0.255 area 0 Passive Interface(s): Ethernet0/0 Routing Information Sources: Gateway. Distance. Last Update. Distance: (default is 110). R1#. Task 5 check ospf neighbors on all the router with show ip ospf neighbor. Verification: On R1: R1# R1#show ip ospf neighbor. Neighbor ID 23.0.0.2 R1#. On R2:. Pri 0. State. Dead Time. Address. Interface. FULL/-. 00:00:36. 12.0.0.2. Serial1/0.

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