Static Routing Routing Protocols and Concepts – Chapter 2 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public ITE PC v4.0 Chapter 1 1 Objectives  D e fin e th e ge n e r a l r o l e a r ou t e r p l ays in n e tw o rk s . e e e ge e a o e a ou e p ays e o s  Describe the directly connected networks, different router interfaces router interfaces  Examine directly connected networks in the routing table and use the CDP protocol table and use the CDP protocol  Describe static routes with exit interfaces  Describe summary and default route  Examine how packets get forwarded when using static routes  Identify how to manage and troubleshoot static routes ITE PC v4.0 Chapter 1 2 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public General Role of the Router  F u n c ti o n s o f a R ou t er ucosoa oue Best Path Selections Forwarding packets to destination  Routers perform packet forwarding by learning about remote networks and maintainin g routin g information. gg – The routers primary forwarding decision is based on Layer 3 information, the destination IP address. – The router's routing table is used to find the best match between the destination IP of a packet and a network address in the routing table. – The routing table will ultimately determine the exit interface to forward the packet and the router will encapsulate that packet in the appropriated data link frame for that outgoing interface ITE PC v4.0 Chapter 1 3 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public the appropriated data link frame for that outgoing interface . General Role of the Router  Intr oduc in g th e T opo l ogy oduc g e opo ogy – The figure shows the topology used in this chapter. – 3 1800 series routers connected via WAN links – Each router connected to a LAN represented by a switch and a PC ITE PC v4.0 Chapter 1 4 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public General Role of the Router  Connections of a Router for WAN -A router has a DB-60 port that can support 5 different cabling standards – Newer routers su pp ort the smart serial pp interface that allows for more data to be forwarded across fewer cable pins.  Connections of a Router for Ethernet -2 types of connectors can be used: Straight through and Cross-over  Straight through used to connect: Straight through used to connect: -Switch-to-Router, Switch-to-PC, Hub-to- PC, Hub-to-Server  Cross - over used to connect (pin 1 connected Cross - over used to connect (pin 1 connected to pin 3, and pin 2 connected to pin 6): -Switch-to-Switch, PC-to-PC, Switch-to- Hub , Hub-to-Hub , Route r -to-Router , PC- ITE PC v4.0 Chapter 1 5 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public , , , Router General Role of the Router in COD  S m a rt Se ri a l cab l es : D C E a n d DTE S a Se a cab es C a d -Use straight cable to connect between the DTE and DCE DCE and DTE Adapter  Ethernet cables:  Cross-over cable: RED cable  Roll-over cable: flat cables  Straight cable: all other cables http://www.csdata.com/csdonline/customer/home.php ITE PC v4.0 Chapter 1 6 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public Serial Connectors DTE DCE DCE DTE DTE DCE DTE DTE DCE  In our labs we will use serial DTE/DCE cables (no CSU/DSU) with a DTE cable connected to one router and DCE bl t d t th th t ITE PC v4.0 Chapter 1 7 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public a DCE ca bl e connec t e d t o th e o th er rou t er. Interfaces  Ex a minin g R oute r In te rf aces a g oute te aces -Show IP router command – used to view routing table -Show Interfaces command – used to show status of an interface -Show IP Interface brief command – used to show a portion of the interface information on a condensed format Sh i fi d dt h fi ti - Sh ow runn i ng-con fi g comman d – use d t o s h ow con fi gura ti on file in RAM ITE PC v4.0 Chapter 1 8 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public Interfaces  Co nfi gu rin g a n E t h e rn et in te rf ace Co gu g a t e et te ace -By default all serial and Ethernet interfaces are down -To enable an interface use the No Shutdown command •The show ip route command is used to display the routing table. •Initially, the routing table is empty if no interfaces have bfid b een con fi gure d . •Static routes and dynamic routes will not be added to th ti t bl til th th e rou ti ng t a bl e un til th e appropriate local interfaces have been configured on the router ITE PC v4.0 Chapter 1 9 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public the router . Verifying Ethernet interface Verifying Ethernet interface - Show interfaces - command shows the status and gives a detailed descri p tion for all interfaces on the route r p – Show interfaces fastEthernet 0/0 – command used to show status of fast Ethernet port R1#show interfaces fastethernet 0/0 • R1#show interfaces fastethernet 0/0 •FastEthernet0/0 is administratively down, line protocol is down • Administratively down means that the interface is currently in the shutdown mode, or turned off. • Line protocol is down means in this case that the interface is not receiving a carrier signal from • Line protocol is down means , in this case , that the interface is not receiving a carrier signal from a switch or the hub. This condition may also be due to the fact that the interface is in shutdown mode • You will notice that the show interfaces command does not show any IP addresses on R1's interfaces The reason for this is because we have not yet configured IP addresses on any of the interfaces . The reason for this is because we have not yet configured IP addresses on any of the interfaces. ITE PC v4.0 Chapter 1 10 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public [...]... the 1 72 16 3 0 /24 R1 1 72. 16.3.0 /24 and 1 72. 16 .2. 0 /24 networks –R2 can communicate with any device on the 1 72. 16.1.0 /24 , 1 72. 16 .2. 0 /24 , and 1 92. 168.1.0 /24 networks –R3 can communicate with any device on the 1 92. 168.1.0 /24 / and 1 92. 168 .2. 0 /24 networks ITE PC v4.0 Chapter 1 © 20 07 Cisco Systems, Inc All rights reserved Cisco Public 28 Routing Table and CDP Protocol Checking each route in turn –The ping... address and subnet mask -Enter in the no shutdown command Example: -R1(config)#interface serial 0/0/0 ( g ) p -R1(config-if)#ip address 1 72. 16 .2. 1 25 5 .25 5 .25 5.0 -R1(config-if)#no shutdown ITE PC v4.0 Chapter 1 © 20 07 Cisco Systems, Inc All rights reserved Cisco Public 18 Interfaces R1(config)#interface serial 0/0/0 R1(config-if)#ip R1(config if)#ip address 1 72 16 2 1 25 5 25 5 25 5 0 1 72. 16 .2. 1 25 5 .25 5 .25 5.0... ITE PC v4.0 Chapter 1 © 20 07 Cisco Systems, Inc All rights reserved Cisco Public 22 Interfaces Once the cable is attached, the clock can now be set with the clock rate command command –The available clock rates, in bits per second, are 120 0, 24 00, 9600, 1 920 0, 38400, 56000, 64000, 720 00, 125 000, 148000, 500000, 800000, 1000000, 1300000, 20 00000, 1000000 1300000 20 00000 and 4000000 4000000 –Some bit rates... shutdown R2(config)#interface serial 0/0/0 R2(config-if)#ip address 1 72. 16 .2. 2 25 5 .25 5 .25 5.0 R2(config-if)#no shutdown –There is no requirement that both ends of the serial link use the same interface, (0/0/0, 0/0/1, 0/1/0, 0/1/1, ….) –in this case, Serial 0/0/0 However, because both interfaces are members of the same network, they both must have IP addresses that belong to the 1 72. 16 .2. 0 /24 network –If... route in turn –The ping command is used to check end to end connectivity –Ping 1 72. 16.3.1 failed •Route does not match any route in the routing table –Ping 1 92. 168.1.1 succeed •1 92. 168.1.0 /24 , matches the first 24 bits of the destination IP address ITE PC v4.0 Chapter 1 © 20 07 Cisco Systems, Inc All rights reserved Cisco Public 29 Routing Table and CDP Protocol Purpose of CDP –Cisco Discovery Protocol... connected physically and share the same data link »R1 and S1 are CDP neighbors »R1 and R2 are CDP neighbors »R2 and S2 are CDP neighbors »R2 and R3 are CDP neighbors R2 d i hb »R3 and S3 are CDP neighbors ITE PC v4.0 Chapter 1 Notice the difference between Layer 2 and Layer 3 neighbors The switches are not neighbors to the routers at Layer 3, because the switches are operating at Layer 2 only only However,... a routing t bl i t provide th router with paths t Th i f ti table is to id the t ith th to different destination networks The routing table consists of a list of "known" network addresses –directly connected, di tl t d –configured statically, –learned dynamically POP Quiz: – Can R1 ping R2? – Can PC1 ping PC2? p g ITE PC v4.0 Chapter 1 © 20 07 Cisco Systems, Inc All rights reserved Cisco Public 25 Routing. .. Layer 3, routing protocols consider neighbors to be devices th t share th same network address space d i that h the t k dd R1 and R2 are neighbors Both are members of the 1 72. 16.1.0 /24 network R2 and R3 are also neighbors because they both share the 1 92. 168.1.0 /24 network But R1 and R3 are not neighbors because they do not share any network address space Layer 2 neighbors CDP operates at Layer 2 only... Chapter 1 © 20 07 Cisco Systems, Inc All rights reserved Cisco Public 23 Testing ITE PC v4.0 Chapter 1 Verifying the Serial Interface Configuration R1#show interfaces R1#show ip interface brief R1#ping 1 72. 16 .2. 2 R1#show ip route © 20 07 Cisco Systems, Inc All rights reserved Cisco Public 24 Routing Table C R ti T bl Concepts t The show ip route command reveals the content of the routing table –The main... routingthe “undebug either Never use the debug all command on the production router ITE PC v4.0 Chapter 1 ip routing command or the “undebug all” command © 20 07 Cisco Systems, Inc All rights reserved Cisco Public 26 Routing Table and CDP Protocol When a router only has its interfaces configured & no other routing protocols are configured then: -The routing table contains only the directly connected networks . 1 72 16 2 1 25 5 25 5 25 5 0  R1(config - if)#ip address 1 72 . 16 . 2 . 1 25 5 . 25 5 . 25 5 . 0  R1(config-if)#no shutdown  R2(config)#interface serial 0/0/0  R2(config-if)#ip address 1 72. 16 .2. 2. Static Routing Routing Protocols and Concepts – Chapter 2 © 20 07 Cisco Systems, Inc. All rights reserved. Cisco Public ITE PC v4.0 Chapter 1 1 Objectives  D e fin e . address 1 72. 16 .2. 2 25 5 .25 5 .25 5.0  R2(config-if)#no shutdown – There is no requirement that both ends of the serial link use the same interface, (0/0/0, 0/0/1, 0/1/0, 0/1/1, ….) –in this case,