WAN (Wide Area Network)

WAN Network

WAN is use to connect network of different geographical areas.

CSU/DSU is a device use in wan, CSU stand for channel service unit. DSU stand for data service unit.

CSU/DSU is use for avoiding local loop.

WAN Technologies: leased line, circuit switching, and packet switching.

1. Leased line technology: in this technology two routers can connect purchased a dedicated line. i.e. E1, T2, T3. E1 line provides 2.048 mbps speed. T2 line provides 1.544 mbps speed. T3 line provides 45 mbps speed. Advantage of leased line: always available. Disadvantage: it is very expensive.
2. Circuit switching technology: work on physical circuit same as telephone line. In circuit switching wireless modem and ISD are used. ISDN (integrated services digital network).
3. Packet switching technology: work on virtual circuit, in this logical bandwidth is build. Same as road/highway which are divided logically.

Types of virtual circuit:

• Permanent virtual circuit (PVC): same as leased line but it is not dedicated; frame relay is use in (PVC)
• Switch virtual circuit (SVC): same as ISDN, ATM is use in switch virtual circuit (SVC)

WAN Protocols: HDLC (high level data link control), PPP (Point to Point Protocol), Frame Relay.

HDLC: always use in leased line, data link layer protocol. HDLC is CISCO proprietary protocol; provide no security (authentication).

To change protocol: Router(config)# interface s0/0

Router(config-if)# encapsulation PPP

PPP: Support multi vendors (CISCO, Juniper etc), can work on lease line and circuit switching. PPP provide security (authentication) for authentication two protocols are used.

• PAP (password authentication protocol): send user name and password in plain text form.
• CHAP (challenge handshake authentication): send user name and password in encrypted form.

PPP consist of two ports: LCP (link control protocol), NCP (network control protocol).

LCP perform following task: connection establishment, compression, authentication, multi-link.

NCP allow multiple routed protocols to send data.

PPP configuration:

Router1(config)# hostname Branch

Branch(config)# enable secret CISCO

Branch(config)# username Head password icne@123

Branch(config)# interface serial 0/0

Branch(config-if)# encapsulation PPP

Branch(config-if)# ppp authentication pap/chap

Branch(config-if)# ip address 10.0.0.1 255.0.0.0

Branch(config-if)# no shutdown

Branch(config-if)# clock rate 64000

Router2(config)# hostname Head

Head(config)# enable secret Microsoft

Head(config)# user name Branch Password icne@123

Head(config)# interface serial 0/0

Head(config-if)# encapsulation ppp

Head(config-if)# ip address 10.0.0.2 255.0.0.0

Head(config-if)# no shutdown

Frame Relay: Frame relay is a packet switching technology, frame relay use a packet switching type called PVC. Frame relay use a number called DLCI (Data link connection identifier).

DLCI use to identify PVC connection, in frame relay leased line but not dedicated.

Encapsulation: Frame relay (only use on CISCO routers), IETF (Globally used).

LMI (local management interface): through LMI packets are share between frame relay routers and switches.

LMI Types: CISCO LMI (use only on CISCO routers)

ANSI LMI (Globally used).

Frame relay configuration

Router1(config)# interface s0/0/0

Router1(config-if)# no ip address

Router1(config-if)# no shutdown

Router1(config-if)# encapsulation frame-relay

Router1(config)# interface s0/0/0.102 point-to-point

Router1(config-router1)# ip address 1.1.1.100 255.255.255.0

Router1(config-router)# bandwith 64

Router1(config-router1)# frame-relay interface-dlci 102

Router1(config-router1)# frame-relay lmi-type cisco, ansi, q933a (optional)

Router1(config)# interface s0/0/0.103 point-to-point

Router1(config-router1)# ip address 2.2.2.100 255.255.255.0

Router1(config-router1)# bandwith 64

Router1(config-router1)# frame-relay interface-dlci 103

Router1# show frame-relay lmi or show frame-relay pvc or show frame-relay map

Router2(config)# interface s0/0/0

Router2(config-if)# encapsulation frame-relay

Router2(config-if)# no ip address

Router2(config-if)# no shutdown

Router2(config-if)# interface s0/0/0.201 point-to point

Router2(config-router2)# ip address 1.1.1.1 255.255.255.0

Router2(config-router2)# bandwith 64

Router2(config-router2)# frame-relay interface-dlci 201

Router3(config)# interface s0/0/0

Router3(config-if)# encapsulation frame-relay

Router3(config-if)# no ip address

Router3(config-if)# no shutdown

Router3(config-if)# interface s0/0/0.301 point-to-point

Router3(config-router3)# ip address 2.2.2.2 255.255.255.0

Router3(config-router3)# bandwith 64

Router3(config-router3)# frame-relay interface-dlci 301

Routing on frame-relay:

Router2(config)# router rip

Router2(config-router)# network 1.1.1.0

Router3(config)# router rip

Router3(config-router)# network 2.2.2.0

Router1(config)# router rip

Router1(config-router)# network 1.1.1.0

Router1(config-router)# network 2.2.2.0

Cloud configuration:

Config > serial1 > lmi (cisco) > dlci (201) > name (r2 to r1) > add.

Serial2 > lmi (cisco) > dlci (301) > name (r3 to r1) > add.

Serial3 > lmi (cisco) > dlci (102) > name (r1 to r3) > add.

Serial3 > lmi (cisco) > dlci (103) > name (r1 to r3) > add.

Frame-relay > select here their paths.

Using DNS to resolve names:

Router(config)# ip domain-lookup

Router(config)# ip name-server 192.168.1.50

Router(config)# ip domain-name corvit.com

Router# ping router2 or show processes

Backup and Restore IOS:

Backup:

Router# show version or show flash (remember the IOS name)

Router# copy flash tftp

Source file name []? Give name of the IOS

Address or name of remote host [] 10.0.0.100

Destination file name [] any

Restore:

Router# copy tftp flash

Router# copy tftp startup-config

Router and Switch configuration software: Hyper terminal, Teraterm (SSH), Secure CRT, Putty.

Switch(config)# interface VLAN 1

Switch(config-if)# ip address 1.1.1.1 255.0.0.0

Switch(config-if)# no shutdown

And give default gateway.

Banner motd: banner is message of the day.

Switch(config)# banner motd @don’t login to the router, if you are not authorized@ > enter

Description:

Switch(config)# interface f0/0

Switch(config-if)# description This is IT department line

SSH (Secure shell):

Switch(config)# aaa new-mode

Switch(config)# username ali password corvit

Switch(config)# ip domain-name Kabul.com

Switch(config)# crypto key generate rsa general-key modelus 1024

Switch(config)# ssh version 2

Switch(config)# line vty 0 4

Switch(config-line)# transport input ssh telnet

Router# show ip arp

Cmd: route print , cmd: tracert –d yahoo.com

To give privilege exec mode permission to users:

Router(config)# line vty 0 4

Router(config-line)# login local

Router(config-line)# transport input telnet

To give permission to one user:

Router(config)# username Ali privilege 15 password CISCO

Router# show run | include network

Router# dir all (shows all memories partitions and IOS).

IP OSPF Authentication key:

Router1(config)# interface s0/0/1

Router1(config-if)# ip ospf authentication

Router1(config-if)# ip ospf authentication-key icne@123

Router1(config)# service password-encryption

Router2(config)# interface s0/0/0

Router2(config-if)# ip ospf authentication

Router2(config-if)# ip ospf authentication-key icne@123

Router2(config-if)# service password-encryption

Note: we must configure the authentication-key command on each port of router, to authenticate. Now without authentication router can’t share its routing table with neighbors.

Internet and VPN (virtual private network):

Advantages: lower cost, security, scalability. Data sends in tunnel by encrypted form, using public network as private network.

Two types of VPN: Site to Site VPN, Remote access VPN.

Note: in remote access VPN, user will install a software by name (CISCO easy VPN) or secure socket layer (SSL) on his laptop.

Redundancy FHRP Technologies:

HSRP (Hot-standby redundancy protocol): CISCO introduced in 1994, hello timer 3 sec, hold timer 10 sec.

Virtual load balancing, Version1 mac(07:ac). Version2 mac(DC:9F).

If R1 wan link were down how R2 know to become active? We will give a command to R1 to decrement priority value. Ex: -20

The higher priority router will be active and second router will be standby.

If R2 3hello packets not received then R2 will be active.

Router1(config)# interface f0/0

Router1(config-if)# standby 1 ip 1.1.1.1 (1 is the group number it will be same on both side)

Router2(config)# interface f0/0

Router2(config-if)# standby 1 ip 1.1.1.1

Router1# show standby brief (router1 changed status to  active and router2 status changed to standby mode.

Router1(config-if)# standby preempt

To change priority:

Router1(config-if)# standby 1 priority 130

Router1(config-if)# standby version 2

When WAN link were down:

Router1(config-if)# standby 1 track s0/0 20

Router2(config-if)# standby 1 preempt

GLBP (Gateway load balancing protocol): CISCO introduced in 2005. AVG (Active virtual gateway), it will reply to all ARP requests for the virtual ip addresses.

AVF(Active virtual forwarder), if Router1 down, the AVF will active the next higher priority router.

If all routers have same priority, then the higher gateway address routers will be AVG.

Router1(config)# interface s0/0

Router1(config-if)# ip address 20.20.20.2 255.255.255.0

Router1(config-if)# no shutdown

Router1(config)# interface f0/1

Router1(config-if)# ip address 1.1.1.2 255.255.255.0

Router1(config-if)# no shutdown

Router2(config)# interface s0/0

Router2(config-if)# ip address 30.30.30.3 255.255.255.0

Router2(config-if)# no shutdown

Router2(config)# interface f0/1

Router2(config-if)# ip address 1.1.1.3 255.255.255.0

Router2(config-if)# no shutdown

Router3(config)# interface f0/1

Router3(config-if)# ip address 1.1.1.4 255.255.255.0

Router3(config-if)# no shutdown

Router1(config)# interface f0/1

Router1(config-if)# glbp 1 ip 1.1.1.1

Router2(config)# interface f0/1

Router2(config-if)# glbp 1 ip 1.1.1.1

Router3(config)# interface f0/1

Router3(config-if)# glbp 1 ip 1.1.1.1

Router3# show glbp

Router(config-if)# glbp 1 load-balancing weighted

Router(config-if)# glbp 1 authentication md5 key-string cisco

Router(config-if)# glbp 1 weighting 110 lower 80 upper 90

Introduction to Cisco switch

Cisoc Switch

Switch is a central device for all computers, switch work on datalink layer of OSI model.

Switch functions: address learning, forward/filtering decision, loop avoidance.

1. Address learning: in address learning switch will find the mac address of every machine
2. Forwarding/filtering decision: in filtering the data send to specific machine
3. Loop avoidance: Loop (the process which repeats again and again is called loop. Avoidance (means removing or stopping through STP and RSTP protocol. Ex: switch#show spanning-tree

Switching: Switching is a process to move the data on the basis of hardware or MAC address.

Data link layer is responsible for switching; data link layer devices are switch and bridge.

ARP (address resolution protocol): ARP is use to find the address from known IP. Ex: cmd: arp –a

Switch# show mac-address-table

Cisco discovery protocol (CDP): CISCO proprietary protocol, works on layer2 (data link layer). Use to find detail information of neighbor device, sends updates every 60 seconds.

Switch# show cdp neighbors

Switch# show cdp entry

Switch# show cdp neighbor’s detail

STP (spanning tree protocol): STP is use to avoid ARP loop. In STP there is secondary path which is always down. Secondary is up where primary is down.

BPDU (bridge protocol data unit): Packet use to share information between switch and STP.

STP secondary link steps:

Step1: select a route bridge, (it is a focal point and decision making switch, which acts as a master for all other switches.

Every switch has priority number, switch have lower priority it will be our bridge. To view switch priority: switch# show spanning-tree

 If priority number is equal, every switch has a mac address a switch with a lower mac address will be our route bridge.

To change the priority number: switch(config)# spanning-tree vlan 1 priority 300 every port of root bridge will be designated port, and it will never block in any condition.

Step2: select root port, is a port of Non-root Bridge. Root port will be selected by cost.

Bandwidth:                             Cost:

10 mbps                                   100

100 mbps                                 19

1Gbps                                        4

10Gbps                                      2

To change cost: switch(config)# interface f0/1

Switch(config-if)# speed 10

Step2: block the redundant link every port (interface) has mac address. The port with higher mac address will be blocked a port in a blocking mode can’t perform any action, except sending and receiving BPDU.

If primary link down a new step, will be started to continue the communication. How the redundant link will know that primary is down? When primary is down either by unplugging or in cause of any damages, secondary or redundant link will follow a few steps to be up.

Step4 startup mode: blocking mode 20 seconds (waiting for primary may be up).

Listening mode 15 seconds (communicating with BPDU).

Learning mode 15 seconds (forwarding mode, startup mode).

How to create switch2 as a root bidge ?

We must decrease the priority of switch2 to make as a root bridge.

Switch2(config)# spaning-tree VLAN1 priority 4096 Or

Switch2(config)# spaning-tree VLAN1 root primary

Switch2# show spaning-tree

Rapid STP (RSTP):

Switch1(config)# interface f0/1

Switch1(config)# spanning-tree port fast

Switch2(config)# interface f0/1

Switch2(config)# spanning-tree port fast

Now run this command on all switches:

Switch1(config)# spanning-tree mode rapid-pvst

Switch2(config)# spanning-tree mode rapid-pvst

Switch3(config)# spanning-tree mode rapid-pvst

Note: after RSTP commands, when the primary path down, the secondary will be up without taking 30 seconds time.

VLAN (virtual LAN): VLAN is a group of ports in which computer can only communicate with their own group members.

Advantage of VLAN: Security will be increased, broadcast will be break.

Two types of VLAN:

Static VLAN: in which ports are manually added.

Dynamic VLAN: in which ports are created by using Mac addresses.

Two ports of VLAN:

Access port: access port carries its own VLAN data.

Trunk port: use to connect two different VLAN.

Switch(config)# vlan 10

Switch(config-vlan)# name sales

Switch(config)# vlan 20

Switch(config-vlan)# name IT

Switch(config)# vlan 30

Switch(config-vlan)# name HR

Switch(config)# interface f0/1

Switch(config-if)# switchport mode access

Switch(config-if)# switchport access vlan 10

To add more interfaces in a vlan:

Switch(config)# interface range fastethernet 0/1 – 5

Switch(config-if-range)# switchport mode access

Switch(config-if-range)# switchport access vlan 10

To add different interfaces in a vlan:

Switch(config)# interface range fastethernet 0/1 , fastethernet 0/4 , fastethernet 0/13

Switch(config-if-range)# switch mode access

Switch(config-if-range)# switchport access vlan 10

Switch# show vlan

VTP (VLAN Trunking protocol): Use to share VLAN information between different switches.

VTP modes: Server mode, Client mode, transparent mode.

Server mode: it is a default mode of every CISCO catalyst switch.

In this mode you can create, delete, and modify VLAN. All VTP information advertised from server to client, in this information are stores in NVRAM.

Client mode: in this mode you can’t create, delete, and modify information are stores in RAM. VTP information sends by VTP server.

Transparent mode: in this mode we create, and delete VLAN. In this mode it has its own database, can’t store VTP information, and send by VTP server.

VTP Configuration:

Switch1(config)# VTP mode server

Switch1(config)# VTP domain corvit

Switch1(config)# VTP password icne@123

Switch1(config)# interface f0/6

Switch1(config-if)# no shutdown

Switch1(config-if)# switchport mode trunk

Switch1# show VTP status

Switch2(config)# VTP mode transparent

 Switch2(config)# VTP domain corvit

Switch2(config)# VTP password icne@123

Switch2(config)# interface range fastethernet 0/6 , fastethernet 0/5

Switch2(config-if-range)# switchport mode trunk

Switch3(config)# VTP mode client

Switch3(config)# VTP domain corvit

Switch3(config)# VTP password icne@123

Switch3(config)# interface fastethernet 0/6

Switch3(config-if)# switchport mode trunk

How to break Router password ?

Step1: reboot the router, when reboot click (ctrl+break) to restrict the router booting from NVRAM, to boot from RAM.

Step2: change that confreg value, i.e. 0x2102

Rommon1> confreg 0x2142

Rommon2> reset

Router(config)# no enable secret or no enable password

Router(config)# config-register 0x2102

Router# copy run start

Router# reload

Inter VLAN routing or router on stick:

Router(config)# interface f0/0

Router(config-if)# no shutdown

Router(config)# interface f0/0.1

Router(config-sub-if)# encapsulation dot1q 10 (vlan 10)

Router(config-sub-if)# ip address 10.0.0.100 255.0.0.0

Router(config)# interface f0/0.2

Router(config-sub-if)# encapsulation dot1q 20

Router(config-sub-if)# ip address 200.0.0.100 255.255.255.0

Router# show ip route

Port security:

Switch(config)# interface f0/1

Switch(config-if)# switchport mode access

Switch(config-if)# switchport port-security

Switch(config-if)# switchport port-security mac-address sticky

Switch(config-if)# switchport port-security maximum 1

Switch(config-if)# switchport port-security violation shutdown

Switch# show port-security

Switch# show port-security address

Switch# show port-security interface f0/1

Switch# show mac-address-table