ca ex s2m02 static routing.ppt [compatibility mode]

8/3/2019 CA Ex S2M02 Static Routing.ppt [Compatibility Mode]

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Chapter 2 - Static Routing

CCNA Ex loration 4.0

1


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Objectives

Define the general role a router plays in networks. Describe the directly connected networks, different router

interfaces Examine directly connected networks in the routing table

and use the CDP protocol

Hc vin mng Bach Khoa - Website: www.bkacad.com 2

Describe summary and default route Examine how packets get forwarded when using static

routes

Identify how to manage and troubleshoot static routes


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Routers and Network



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Role of the Router

The router is a special-purpose computer that plays a key role in theoperation of any data network.

Routers are primarily responsible for interconnecting networks by:1. Determining the best path to send packets

2. Forwarding packets toward their destination



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Introducing the topology

Topology Lab



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Introducing the topology

Topology Lab



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Reference: Cisco router 1841s Component

Product Description Quantity

CISCO1841Modular Router w/2xFE, 2 WAN slots, 32FL/128 DR 1

CAB-ACE Power Cord Europe 1

S184IPB-12406T Cisco 1841 IOS IP BASE W/O CRYPTO 1


WIC-2T 2-Port Serial WAN Interface Card 1

CAB-SS-V35FCV.35 Cable, DCE Female to Smart Serial, 10Feet 2

CAB-SS-V35MT V.35 Cable, DTE Male to Smart Serial, 10 Feet 2

MEM1800-32CF 32MB Cisco 1800 Compact Flash 1

ROUTER-SDM-CD CD for SDM software 1

CON-OSP-CISCO1841 ONSITE 24X7X4 Modular Router w/2xF 1


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Cable Standards



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Cable Standards



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Cable for LAN/WAN interfaces



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Examining the Connections of the Router


Serial Connectors DB-60 port and Smart port: five-in-one serial port:

EIA/TIA-232, EIA/TIA-449, V.35, X.21, and EIA/TIA-530standards


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Examining the Connections of the Router


Ethernet Connectors 2 types of connectors can be used: Straight through and Cross-over Straight through used to connect:

Switch-to-Router, Switch-to-PC, Router-to-Server, Hub-to-PC, Hub-to-Server Cross-over used to connect:

Switch-to-Switch, PC-to-PC, Switch-to-Hub, Hub-to-Hub, Router-to-Router


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Router Configuration Review



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Examining Router Interfaces

Examining Router Interfacesshow ip routecommand used to view routing

tableshow interfacescommand used to show

status of an interface


show ip interface briefcommand used toshow a portion of the interface information

show running-configcommand used to

show configuration file in RAM


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Configuring an Ethernet Interface

Configuring an Ethernet interface By default all serial and Ethernet interfaces are down

To enable an interface use the no shutdowncommand



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Configuring an Ethernet Interface

Verifying Ethernet interface Show interfaces for fastEthernet 0/0 command used to show

status of fast Ethernet port

show ip interface brief

show running-config

Ethernet interfaces participate in ARP



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Extra: Testing using the OSI Model



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Logging Synchronous Command

In order to keep the unsolicited output separate from your input,enter line configuration mode for the consoled port and add the

logging synchronous command.


Line console 0

Logging synchronous


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Configuring a Serial Interfaces

Configuring a Serial interface Enter interface configuration mode

Enter in the ip address and subnet mask

Enter in the no shut down command

Example: R1(config)#interface serial 0/0


con g- p a ress . . . . . .

R1(config-if)#no shutdown


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Activity 2.2.5.1 Examining Router Interfaces

Physically connecting a WAN Interface.

A WAN Physical Layer connection has sides:

-


This is the service provider. CSU/DSU is a DCEdevice.

Data Terminal Equipment (DTE) Typically the

router is the DTE device. Devices are responsible for converting the data from

the WAN service provider into a form acceptable bythe router: modem, CSU/DSU


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on gur ng ser a n s n a a env ronmen One side of a serial connection must be considered a DCE This requires placing a clocking signal use the clock rate

command. Example:

R1(config)#interface serial 0/0 R1(config-if)#clock rate 64000 Serial Interfaces require a clock signal to control the timing of

the communications. Note: WIC-2a/s support maximum clock rate is 128000 bps


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Extra: Clock Rate

RouterB(config)#inter serial 1

RouterB(config-if)#clock rate ?


pee s per secon

12002400

4800

9600

2000000

4000000

Choose clockrate from list above

RouterB(config-if)#clock rate 64000

RouterB(config-if)#


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Verifying the Serial Interface Configuration show interfaces

show ip interface brief show running-config

ping



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Verifying Changes to the Routing Table

The routing table consists of a list of "known" network addresses- that is, those addresses that are directly connected, configured

statically, and learned dynamically.



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Verifying Changes to the Routing Table

Observing Routes as They are Added to the Routing Table debug ip routingcommand will let us see any changes that

the router performs when adding or removing routes.



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11

Router# debug ip routingRouter# no debu i routin

Router#undebug all

(# u all)



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Devices on Directly Connected Networks

When a router only has its interfaces configured, and the routingtable contains the directly connected networks but no other

routes, only devices on those directly connected networks are

reachable.



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Devices on Directly Connected Networks



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Extra: Directly Connected Networks and the IP Routing Table

RTA# debug ip routing

RTA(config)#inter e 0

RTA(config-if)#shutdown

00:34:38: RT: interface Ethernet0 removed from routing table

00:34:38: RT: del 192.168.2.0 via 0.0.0.0, connected metric [0/0]

00:34:38: RT: delete network route to 192.168.2.0

RTA#show ip route

-


Viewing the Routing Table Process

Directly connected routes will also be removed if the link goes down. Directly connected routes will only be in the routing table if, it is not

administratively down, the line is up and protocol is up

For serial interfaces, dont forget the clock rate command on the routerwith the DCE cable neither interface will be up and up until both ends

are configured correctly.

,..

RTA# undebug all


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RTA#show ip routeCodes: C - connected,..

C 172.16.0.0/16 is directly connected, Serial0

C 192.168.2.0/24 is directly connected, Ethernet0

172.16.0.0/16 192.168.1.0/24

.1 .1.2 .2

RTA RTB RTC

192.168.2.0/24

.1 .1

10.0.0.0/8

s0 s0 s1s1e0 e0


RTB#show ip route

Codes: C - connected,..



RTC#show ip route

Codes: C - connected,.. C 10.0.0.0/8 is directly connected, Ethernet0


The Routing Tables Notice that the routers only know about their own directly connected networks.

They are not sharing routing information because we have not configured any static routes ordynamic routing protocols.


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RTA#show ip route



RTA#ping 172.16.0.1

!!!!!

172.16.0.0/16 192.168.1.0/24

.1 .1.2 .2

RTA RTB RTC

192.168.2.0/24

.1 .1

10.1.0.0/16

s0 s0 s1s1e0 e0


Routers can only reach networks known about in its own routing table.

RTA#ping 172.16.0.2

!!!!!

RTA#ping 192.168.1.1

.....

RTA#ping 192.168.1.2

.....

RTA#ping 10.1.0.1

.....


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Extra: Extended Ping Command

RTA#show ip route



172.16.0.0/16 192.168.1.0/24

.1 .1.2 .2

RTA RTB RTC

192.168.2.0/24

.1 .1

10.1.0.0/16

s0 s0 s1s1e0 e0


RTB#show ip route

Codes: C - connected,.. C 172.16.0.0/16 is directly connected, Serial0


RTA#ping

Protocol [ip]:

Target IP address: 172.16.0.2

Extended commands [n]: ySource address or interface: 192.168.2.1

Sending 5, 100-byte ICMP Echos to 172.16.0.2, timeout is 2 seconds:

.....

RTA#ping 172.16.0.2 source 192.168.2.1


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12- Extended PING

Ping A.B.C.D source A.B.C.DPing


E t Li t th ibl t t h t f th Pi


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Extra: Lists the possible output characters from the Pingfacility



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Extra: IP Traceroute Text Characters



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Cisco Discovery Protocol (CDP)

Network discovery with CDP

CDP is an information-gathering tool used by network administrators toget information about directly connected Cisco devices.

CDP is a proprietary tool that enables you to access a summary ofprotocol and address information about Cisco devices that are directlyconnected.

These advertisements contain information such as the types of devices


that are connected, the router interfaces they

are connected to, the interfaces used to

make the connections, and the model

numbers of the devices.

Concept of neighbors 2 types of neighbors

Layer 3 neighbors

Layer 2 neighbors


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Cisco Discovery Protocol (CDP)

CDP Operation

CDP runs at the Data Link layer connecting the physical media to theupper-layer protocols (ULPs).

Cisco network devices, such as routers that support different Networklayer protocols (for example, IP and Novell IPX), can learn about eachother


device:Device identifiers

Address list

Port identifier

Capabilities list

Platform


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Default Setting

Feature Default Setting

CDP global state Enabled


nter ace state na e

CDP holdtime (packet holdtime in seconds) 180

CDP timer (packets sent every x seconds) 60


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Using CDP for Network Discovery

The information gathered by the CDP protocol can beexamined with the show cdp neighbors command.


C


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Field Definition

Device ID The name of the neighbor device and either the

MAC address or the serial number of this

device.


Local Intrfce The protocol being used by the connectivitymedia.

Holdtme The remaining amount of time (in seconds) the

current device will hold the CDP advertisementfrom a sending router before discarding it.

U i CDP f N k Di


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Capability

(Capability

Codes)

Capability (type of routing device) of the listed

neighboring device.

The capability types that can be discovered are:

RRouterTTransparent bridge

BSource-routing bridge


SSwitch

HHost

I device is using IGMP

rRepeater

Platform The product number of the device.

Port ID The protocol and port number of the device.

U i CDP f N t k Di


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14

# show cdp neighbors


# show cdp neighbors detail

CDP C d


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CDP Commands


CDP Commands


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CDP Commands


CDP Commands


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CDP Commands


CDP Commands


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CDP Commands



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Static Routeswith Next Hop Addresses


Purpose and Command Syntax of ip route


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Static routes are commonly used when routing from a network toa stub network.

A stub network is a network accessed by a single route.




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R1(config)# ip route 192.168.3.0 255.255.255.0 f0/0

R1(config)# ip route 192.168.3.0 255.255.255.0 192.168.2.2


R1(config)# ip route 192.168.3.0 255.255.255.0 f0/0 192.168.2.2

Configuring Static Routes


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Configuring Static Routes

Installing a Static Route in the Routing Table


Verifying Static Route Commands


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Verifying Static Route Commands

Configuring Routes to Two More Remote Networks


Routing Table Principles and Static Routes


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g p

Applying the Principles


Resolving to an Exit Interface


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g


Resolving to an Exit Interface


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g

Exit Interface is down


Extra: Static Routing Recursive Lookups


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RTA(config)#ip route 192.168.1.0 255.255.255.0 172.16.0.2

RTA#show ip route

172.16.0.0/16 192.168.1.0/24

.1 .1.2 .2

RTA RTB RTC

192.168.2.0/24

.1 .1

10.1.0.0/16

s0 s0 s1s1e0 e0

g p


Co es: C - connecte , S - stat c,

C 172.16.0.0/16 is directly connected, Serial0S 192.168.1.0/24 [1/0] via 172.16.0.2


12


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RA(config)# ip route 192.168.1.0255.255.255.0 172.16.0.2

RA#ping 192.168.1.1

RA(config)# ip route 192.168.1.0255.255.255.0 s0/0


Extra: Static Routing Recursive Lookups


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RTA(config)#ip route 10.1.0.0 255.255.0.0 192.168.1.2

RTA#show ip route

Codes: C - connected, S - static,

172.16.0.0/16 192.168.1.0/24

.1 .1.2 .2

RTA RTB RTC

192.168.2.0/24

.1 .1

10.1.0.0/16

s0 s0 s1s1e0 e0



S 192.168.1.0/24 [1/0] via 172.16.0.2

S 10.1.0.0/16 [1/0] via 192.168.1.2


2

3


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RA(config)#ip route 10.1.0.0255.255.0.0 192.168.1.2

con g p rou e . . .255.255.0.0 192.168.1.2



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RA(config)#ip route 192.168.1.0255.255.0.0 s0/0

RA(config)#ip route 10.1.0.0 255.255.0.0s /

RB(config)#ip route 10.1.0.0 255.255.0.0

s0/0 RA(config)#ip route 172.16.0.0

255.255.0.0 s0/1Hc vin mng Bach Khoa - Website: www.bkacad.com 63

Extra: Static Routing Endless Recursion


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Route1: ip route 10.1.0.0 255.255.0.0 20.1.1.1


Route2: ip route 20.1.0.0 255.255.0.0 30.1.1.1 Route3: ip route 30.1.0.0 255.255.0.0 10.1.1.1


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Static Routes with Exit Interface


Configuring a Static Route with an Exit Interface


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Static routes can be configured with an exit interface, whichallows the routing table to resolve the exit interface in a single

search instead of two searches.


Configuring a Static Route with an Exit Interface


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Static Route and an Exit Interface


Modifying Static Routes


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There are times when a previously configured static route needs to bemodified:

The destination network no longer exists, and therefore the staticroute should be deleted.

There is a change in the topology, and either the intermediateaddress or the exit interface has to be changed.


Verifying the Static Route Configuration


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Use the following commands Step 1: show running-config

Step 2 verify static route has been entered correctly

Step 3: show ip route

Step 4 verify route was configured in routing table

Step 5 issue pingcommand to verify packets can reach destination


an a e urn pa s wor ng

Static Routes with Ethernet Interfaces


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Ethernet interfaces and ARP. If a static route is configured on an Ethernet link, if the packet is

sent to the next-hop router then

the destination MAC address will be the address of the nexthops Ethernet interface

This is found by the router consulting the ARP table


Static Routes with Ethernet Interfaces


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Static routes and Ethernet exit interfaces

With Ethernet networks, may be many different devices sharingthe same multi-access network so the router does not know the

next-hop IP address and it cannot determine the destinationMAC address for the Ethernet frame.



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RA(config)#ip route 192.168.1.0255.255.255.0 f0/1

RA(config)#ip route 10.1.0.055. 55. 55. f /1


Extra: Static Routing Ethernet interfaces


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172.16.0.0/16 192.168.1.0/24

.1 .1.2 .2

RTA RTB RTC

192.168.2.0/24

.1 .1

10.1.0.0/16

s0 s0 s1s1e0 e0

RTA(config)#ip route 192.168.1.0 255.255.255.0 eth1 172.16.0.2

RTA#show ip route

e1 e0


Static routes via point-to-point links

It is best to configure static routes with only the exit interface.

Static routes via broadcast networks such as Ethernet

It is best to configure static routes with both the next-hop addressand the exit-interface.

Codes: C - connected, S - static,

C 172.16.0.0/16 is directly connected, Ethernet1S 192.168.1.0/24 [1/0] via 172.16.0.2 Ethernet1



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Summary and Default Static Routes


Summary Static Routes


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Summarizing Routes to Reduce the Size of the Routing Table Route Summarization: Multiple static routes can be summarized into a

single static route if:

The destination networks can be summarized into a single networkaddress, and

The multiple static routes all use the same exit-interface or next-


Summary Static Routes


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Configuring a Summary Route:

Step 1: Delete the currentstatic route

Step 2: Configure thesummary static route


route

Host 1

172.16.1.0/24

Extra: Summarizing static routes


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Hub

S0S0

S0 S1

E0

172.16.2.0/24 192.168.1.0/24

SanJose2

SanJose1

Baypointe

.1

.1 .1

.2.2172.16.0.0/22


Baypointe(config)# ip route 172.16.1.0 255.255.255.0 192.168.1.2 Baypointe(config)# ip route 172.16.2.0 255.255.255.0 192.168.1.2 Baypointe(config)# ip route 172.16.3.0 255.255.255.0 192.168.1.2 Summarized route:Baypointe(config)#ip route 172.16.0.0 255.255.252.0 192.168.1.2

Host 2 Host 3

Hub Hub

172.16.3.0/24 192.168.2.0/24

..

Default Static Route


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A default static route is a route that will match all packets. Default staticroutes are used:

When no other routes in the routing table match the packet'sdestination IP address. In other words, when a more specific match

does not exist. A common use is when connecting a company'sedge router to the ISP network.

When a router has only one other router to which it is connected.


This condition is known as a stub router.

Default Static Route


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Verifying a Default Static Route


Extra: Common uses for Static Routes


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ISP

10.1.1.2/24

10.1.1.1/24

ip route 172.16.0.0 255.255.0.0 10.1.1.2

Default


172.16.0.0/16ip route 0.0.0.0 0.0.0.0 10.1.1.1

RTB#show ip route

Gateway of last resort is 10.1.1.1 to network 0.0.0.0


10.0.0.0/24 is subnetted, 1 subnets

C 10.1.1.0 is directly connected, Serial1

S* 0.0.0.0/0 [1/0] via 10.1.1.1


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Managing and


Static Routes and Packet Forwarding


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Troubleshooting a Missing Route

T l h b d i l i bl


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Tools that can be used to isolate routing problemsinclude:

ping tests end to end connectivity

traceroute used to discover all of the hops(routers) along the path between 2 points


show IP route used to display routing table &

ascertain forwarding process

show ip interface brief- used to show status ofrouter interfaces

show cdp neighbors detail used to gatherconfiguration information about directly connectedneighbors

Solving the Missing Route

Fi di i i i fi d t i th di ll i


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Finding a missing or miss-configured route requires methodically usingthe correct tools

Start with ping. If ping fails then use tracerouteto determinewhere packets are failing to arrive

Issue: show ip route to examine routing table. If there is a problem with a miss-configured static route remove the


Solving:

R2(config)#no ip route 172.16.3.0 255.255.255.0 serial0/0/1

R2(config)#ip route 172.16.3.0 255.255.255.0 serial 0/0/0

Q/A

Whi h t i ld i


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Which two scenarios would require anadministrator to alter the static routes that areconfigured on that router?

The destination network no longer exists.

A to olo chan e occurs where the existinnext-hop address or exit interface is notaccessible.


Basic Static Route Configuration Lab


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Challenge Static Route Configuration Lab


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Summary


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ca ex s2m02 static routing.ppt [compatibility mode]

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