INTER VLAN ROUTING:

 The inter-vlan routing  is a proporties of in vlan routing. there are some point about inter vlan routing.


  VLANs divide broadcast domains in a LAN environment. Whenever hosts in one VLAN need to communicate with hosts in another VLAN, the traffic must be routed between them. This is known as inter-VLAN routing. On Catalyst switches it is accomplished by the creation of Layer 3 interfaces (switch virtual interfaces (SVIs) )
Consider, this, as the network administrator, one of your tasks is to create and assign different users to VLANs in your network, you have three main departments which should be logically segmented using VLANs, VLAN 10 – FINANCE, VLAN 20 – SALES and VLAN 30 – HR.
The use of VLANs means that users would not be able to communicate across departments, i.e. a user in FINANCE, would not be able to send a message to a user in SALES since they are on different broadcast domains.
In many enterprises, you will find that information sharing across departments is a requirement, therefore, the question begs, how do you make users in the SALES and FINANCE department communicate, yet they are on different VLANS?

HOW TO RECOVER/BREAK PASSWORD IN ROUTER

 BREAK / RECOVER PASSWORD IN ROUTER:-

There are some step to break / recover password in router.

step1.  Connect console cable with computer.

step2. open putty //command.

step3/ .Restart Router and press ctrl+c or ctrl+shift+break at time while rebooting of router.

step4. now you will be in rommon mode ,it is an factory default.is  like this in fig.    

step5. write  confreg 0x2142, then press enter. as like in above fig.

step6. rommon2> write reset press enter. and waite a minute.

step7. Now come in privilege mode ,and write

step8. show startup config

step9.copy startup config   as like in below fig.

step10. running config  , after this write code as in fig.

step11.no enable secret ,thi as like in fig

step12. Configure resister ox2102

step13. end

step14. write

step15. reload.

Click here to go to ios backup of router:

PASSWORD IN ROUTER

Password for Router:-

there are we tell aboute three types of password for security purpose.

Consol password;-

this password is used in router to secure the consol port of router or also authentication verifying for entry in user mode.in given below  picture show you a commond for consol password and it is define in configure mode.

note -where xyz->any password you can write

Auxiliary port password;-

This password is used to secure auxillary port of router from any user. this password is also command in configure mode of programe.

note -where xyz->any  password you can write.

Privileged  mode password:-

Privileged  mode password is used to stop unknown user to enter  in the  privileged mode. here we used a two types of password .

Clear text password:-

in this password system any body show your password on display. throw cmd

note -where xyz->any  password you can write.

Encrypted password :-

This password is secret password ,it is a strong password it is restored in encrypted form.

Note :- encrypted password and clear text password neve can be same.

How to recover/break password, click here

TELNET AND SSH

 TELNET AND SSH(Secure Shell):

 Telnet:

(1).  It is used to remotely control /access the Router.
(2). the port no. is define as 23.
(3). Telnet is based on tcp & it can be used to have an interface tcp connection of protocols.
(4). To login the server ,telnet assign username and password.
(5). it is unseccured.

TELNET AND SSH  SETUP

Telnet configuaration:-

 for telnet confiquaration we should follow bellow cmd in system cli.


step(1). line vty 0 4(here we can write any number for confiquaration from no. of computer. example  : we want to access tellnet from 3 computer then we write there 0 2. ).
NOTE: Any system can access only 16 computer for telnet at one time.

 step(2). login local
step3. username  abc  password cisco@200 (you can use any username/ passwoed in place of abc / cisco@200).
step4.  exit.
step5. enable secret xyz(xyz is a password can change it).
step 6. do write.

in this fig is telnet confi. in router.

In fig here laptop 7 is used for remotely configuration.

CONFIGURATION IN REMOTLY COMPUTER 7

in fig show you configuration in laptop 7.

SSH(Secure SHell):-

1. SSH stand for secure shell .
2. SSh was developed by SSH community security ltd.
3. Secure shell is a protocol used for a secure connection between two system . in this protocols ,the client machine initiates a connection with a server machine.
4. The clienttransmit it authentication info to the server such as  ausername and password in an encrypted form.
5. The entire data send recieve during the connectio  is  transfered using strong 512 bits encryption ,making it extremly different and strong realistic.

SSH CMD:-

Note :- SSh support RSA encrypted mode.
step 1. line vty 0 5.
step2. login local
step3. exit
step4. username xyz  password abc (here xyz and abc are username and password respectively. you cant change it.)
step5. enable secret xxx
step 6. hostname r2 (hostname is must required for ssh confiquaration).
step7. ip domaim name example.com(can ive any domain name)
step 8. crypto key generate rsa

Now go to pc 7 in commond
step1. ssh-l (it is L not one) admin 192.168.1.1  (here admin means username xyz)
step2. password

OSPF(Open Shortest Path First) Dynamic Routing

   OSPF DYNAMIC ROUTING :

1. ospf stand for open shortest path first. and it is  layer 3 protocal.

2. Open Shortest Path First (OSPF) is an open standards routing protocol that’s been implemented by a wide variety of network vendors, including Cisco.

3. OSPF converges quickly, although perhaps not as quickly as EIGRP, and it supports multiple, equal-cost routes to the same destination. 

 4.Administrative distance (AD) value is 110 and protocol no . is 89.

5. It use dijkstra algorithum to find best path.

6. Ospf supposed to be designed in a hierachical fashion, which basically means that you can separate the larger iinternetworks into

 smaller      internetwork called areas.

7. OSPF support only ip networks.

8. OSPF send routing table with unicaste /multicast with the 224.0.0.5 and 224.0.0.6  .

9. OSPF used process id (1- 65535) always effect locally not globally.

10. it is classless routing and support VLSM.And used wild-card mask (inverse of subnett mask).


OSPF CONFIGURATION: 

STEP 1.  router ospf 2( it is a proccess id)
step2. network 1.0.0.0( network ip address)  0.255.255.255(wildcard-mask  ) area 10.
step 3 . do wr.
see in ass fig. 

                      

ospf confiquration

     here in the fig we used
10.0.0.0 in place of 2.0.0.0  .for loopback 0.
.

  OSPF TERMINOLOGY:

LINK: - A link is a network or router interface assigned to any given network.

ROUTER ID: - The router id is an IP address used to identify the router. CISCO chooses the router id by using the highest IP address of all configured loopback interface.

NEIGHBOR: - neighbors are two or more routers that have an interface on a common network, such as two routers connected on a point to point serial link.

 ADJANCECY: - An adjacency is a relationship between two OSPF routers that permit the direct exchange of route updates.

 Neighbor ship database: - The neighbor ship database is a list of all OSPF routers for which hello packet has been send.

 

Link state advertisement: - A link state advertisement (LSA) is an OSPF packet containing link state and routing information that’s shared among OSPF router.

 

                                                                                      OSPF AUTHENTICATION:

 

  There are three types of authentication support by ospf routing.

  1. Null Authentication.

  2. clear text Authentication .

 

            

clear text authentication

 

  3. MD5 Authentication.

 

                     

md5 authentication

 

 

NOTE :- this above fig code used for ospf authentication on interface.

EIGRP(Enhanced Interior Gateway Routing Protocol)

 EIGRP DYNAMIC ROUTING:-   

                                                           
EIGRP stand for Enhanced Interior Gateway Routing Protocol.

 1. Cisco proprietary protocol .

2.   EIGRP is a classless, enhanced distance vector protocol that gives us a real edge over another Cisco proprietary protocol.

 

3.   EIGRP is sometimes referred to as a hybrid routing protocol because it has characteristics of both distance-vector and link-state protocols.

4.   EIGRP use 224.0.0.10 multicasts address to communicate with each other.

 

5.  Maximum hop count 255

 

6.  Maximum hop limit by default 100 ..

 

7 .Administrative distance value is 90 . class="auto-style8">Eigrp port no. is 88.

8. Load balance – 4 by default.

 

9. Maximum path = 16 .

 

10. Neighbor ship is created by hello message.

 

 11. Hello time interval in LAN-5/sec, hold-down=15/sec, in WAN=60/sec, holddown= 180/sec.

 

EIGRP NEIGHBOR  CONDITIONS:

1.  EIGRP routers are willing to exchange routes with each other, they must become neighbors.  There are 4 conditions that must be met for neighbor ship establishment .
2. Hello or ACK received. .
3. AS(Autonomus number 1-65535) number should match .
4. Identical metrics ( K value must match) .
5. Authentication must match.
EIGRP CONFIGURATION :-
STEP 1 > go to in configuration mode.
and follow as in fig.

         

               yo can code indivisually.
NOTE: For checking  neighbor write:  show ip eigrp 1 neighbor.

EIGRP AUTHENTICATION:

 Now i will learn about how to secure my eigrp routing throw eigrp authentication.

lets start: EIGRP support only md5 / encrypted authentication.

step/cmd 1.key chain vinit

step/cmd 2. key 2.

step/cmd 3.  key string cisco@123.

after these command goto in interface of router. and give cmd.

cmd 1.  ip authentication mode eigrp 100(atonomus number) md5.

cmd 2. ipauthentication ke chain eigrp 100 vinit(key name).

example of code in eigrp routing with fig.

                        

eigrp maintain three tables:-

1.Neighbor Table:It contains list of directly connected to router.

2. Topology Table: It contains list of best path and alternate best path.

3. Routing Table:- it contains only best path of routing.

SOME IMPORTANT TERMS OF EIGRP:-

1. FD(Fessible Distance)"- total distamce between source to destination.

2. Successor :- Best path between source to destination  (lowest fd in successor).

3. Feassible Succesor:- second best path between source to destination.

RIP(Routing Information Protocol)

  RIP confiquaration. via fig:

rip topology

 

 RIP version 1 config.

note : all coding is in config. mode-

 step1.  Router(config t)#Router rip                    (enable rip routing protocol on router) Router(config-router).

step2.  #Version  1                                         (configure router to support rip version 1 or default as version1) .

Note: without this version command router default supports version 1 Router(config-router).

step3. #Network 10.0.0.0                           Note: (advertise directly connected netwroknid not ip, if you are implementing subnetting ip range on lab topology use NID or network ) .
syep4. do wr.
 

                   

RIPversion 2 config.

step1.  Router(config t)#Router rip                    (enable rip routing protocol on router) Router(config-router).

step2.  #Version 2                                           (configure router to support rip version 2) .

Note: without this version command router default supports version 1 Router(config-router).

step3. #Network 10.0.0.0                           Note: (advertise directly connected netwroknid not ip, if you are implementing subnetting ip range on lab topology use NID or network ) .
syep4. do wr.

            

    IN fig defines more than one network.


EIGRP DYNAMIC ROUTING click here ::

RIP(Routing Information Protocols) Authentication:-

 Rip Authentication  support clear text and md5 authentication .
see and follow in fig now.
1. clear text authentication:

                 

2. MD5 authentication/encrypting form authentication in RIP:
In       md5 authentication same as clear text ,but only change in interface coding ,so see and follow the fig.

NOTE:- After any programming/coding save with "do wr " code.
                                    

DYNAMIC ROUTING

WHAT IS DYNAMIC ROUTING AND ITS TYPES:

 1.  Dynamic routing is the process of routing protocols running on the router communicating with neighbour routers.
2. This automatically created route by the router in a network with the help of protocols.

3. Once the path is determined, a router can route a routed protocol.

There are two protocols who is responsible for dynamic routing:-

1. Routing protocol:- it is used by router to send the update message or communicate with other router in a network.
2.Routed protocol:- it carry network traffic for routing protocols. Examples of routed protocols are ip, ipx, apple talk etc.

Types of routing protocols:-

1. IGP ( intergral gateway protocol):- it is a protocol that works within a logical boundry in term of CCNA/CISCO.this logical boundry is called autonomous system.Example:- RIP, IGRP, EIGRP, OSPF, IS- IS ,

  RIP:-  Routing information protocol .
  IGRP :- Internal gateway routing protocol .
  EIGRP:- Enhance interial gateway routing protocol .
  OSPF:- Open shortest path first.
  IS-IS :- Intermediate system- intermediate system .

2. EGP ( Exterial gateway protocol):- protocol that work between two autonomous system is called EGP. Like:- BGP (Border gateway protocol) .

  RIP(Routing Information Protocol):-

     1.It is a Open System Protocols ,mean can run at any router easily.

 2. it is classfull routing protocols(mean not carry subnet mask).

 

3. RIP only uses hop count to determine the best way to a remote network, but it has a maximum allowable hop count of 15, meaning that 16 is deemed unreachable.

 

4. Administrative distance value of rip is 120 .

 

5.RIP support UDP port n. 520

6. Routing Information Protocol (RIP) is a true distance-vector routing protocol.

 

7. load ballancing up to 4 equal part .

 

8. exchange entire routing table for every 30 second.

 

9. It works on application layer .and have two types Ripv1 and Ripv2.

 

DIFFERENTIATE BETWEEN RIP-V1 AND RIP-V2.

 

RIP-V1                                             1. It is classfull.  2.Broadcaste 225.255.255.255 3. No authentication support. 4. Not support summerisation. 5. it support v1 and v2 both.

RIPV2     1.It is classless.     2. Multicast  224.0.0.9     3. support  Authentication.     4. Support auto summurised and mannual summerised.

WHAT IS ROUTING IN NETWORKING:

1. IT is a  process in which used to find route between source to destination.

2. it is also used to select best path with the help of roting protocols.

3. In routing there is no need of gateway in same network /same router.

4. Every router maintain there own routing table.

5. Routers build routing tables initially based on their directly connected networks.

 

1. there are three types of routing protocols.

• Static routing protocols .

• Default routing protocols.

• Dynamic routing protocols.

                                              what is Routing table?

1.Routing tables are used to send data along specific paths to reach a particular destination.

2.Routers need to exchange routing tables so they can route data to networks that are not directly connected to them.

 

3. Routers require a Routing Protocol in order to exchange routing tables with their neighboring routers and advertise networks.

 

4. Static Routes: Manually added to the routing tables by the administrator.

 

5. Default Routes: Manually added to the routing table by the administrator to define a Default Gateway for the router. If the routing table does not have an entry for a destination network, send the packet to the Default Route.

 

6.Dynamically Learned through a Routing Protocol.

 

                                        

    STATIC ROUTING:-

Static Routes are User-defined, manually created routes. The administrator creates Static Routes in a Cisco Router using the IP Route Command .
1.IN Static Routing administration must be defines every destination address in every router manually.
2. it is a trusted routing protocols.
3.Hard to implement.
4. It is suitable for small network.

Commond in confiquaration mode for static  routing protocols :

1. # ip route.

2. # destination  IP address   subnetmask of destination ip  gateway of starting network.

example:    see in fig.

                               

 now we see example according to fig , i am in R1 place and i want to send a message to R3 network .so lets  give commond according to fig . 

so we have : 1 .  Destination ip = 193.168.1.2,  and Subnet mask = 255.255.255.0 , Gateway  192.168.1.2(every directly connected network will be gateway.)

statix figure

                                         

static configuration command

  you can match the fig.

                                         DEFAULT ROUTING PROTOCOLS:-

DEFAULT- ROUTING:-  In  Default routing  destination address is unknown always(0.0.0.0) .

 >   it is used to forword the package as like multicasting.

>   Default Routes define a router as the default router for your router. When there is no entry for the destination network in a routing table, the router will forward the packet to its default router. Default routes help in reducing the size of your routing table.

>. It is untrusted Routing .

>. It is used to networking in between  for ISP to costumer.

>,The device to which the default route points is often called the default gateway, and it often carries out other functions such as packet filtering, firewalling, or proxy server operations.

>The default route in Internet Protocol Version 4 (IPv4) is designated as the zero-address 0.0.0.0/0 in CIDR notation,^[1] often called the quad-zero route.

CONFIGURATION OF DEFAULT ROUTING:

   Default routing confiquarationis simple as static routing in default configuration is same as static routing but only change is that in destination address we used ip = 0.0.0.0  and subnet-mask 0.0.0.0 (ip route 0.0.0.0 0.0.0.0 10.0.0.2) . as  like ib fig,

                               

DYNAMIC ROUTING CLICK HERE

 Administrative distance:- The administrative distance(AD) is used to rate the trustworth of routing information received on a router from a neighbor router. If you have more than one route to destination and all route having different routing protocol. The router choose path based on AD value. It is between 0- 255. 0 is the most trusted and 255 is trustless where no traffic will be passed via this network.

What is use of IP Assign in Router

The ip assigning method is use to give a particuller or dynamic addressing of a system to easly communicate each other.
The ip address contains of 32 bits data,and defined as 1.1.1.1 .
The ip address contents of Network id and Host id ,each part of ip address are of 8 bits.

Follow the step to assign an ip address.

 

step1.  Open Router configuration mode.

step2.  Inter in the interface of Router(like as , int s0/0).

step 3.  Types  ip add 192.168.1.1(this is your ip address,whicj can b differ as like you)   255.255.255.0(subnet mask).

step 3. no shut and then press do wr.

Now your ip have been assign

BASIC CONFIGURATION OF ROUTER

 Basic configuration of router:-

Routers can be configured from: Console terminal

Auxiliary port – externally, via modems

 Virtual terminals (Telnet) – after installation

INTERNAL CONFIGURATION COMPONENTS :

RAM:-

 Contains dynamic / running configuration

 NVRAM:-

 Contains backup of configuration (startup configuration)

 Flash:-

 Contains copy of Cisco IOS

 ROM :-

Contains a subset of IOS

 Contains bootable IOS image

 Interfaces :-

Network connections which packets enter/exit from routers, e.g. Ethernet, serial, BRI, Token Ring

 Console and auxiliary ports:-

 Main command-line interface used for configuration

ROUTER STARTUP SEQUENCE –

1. Bootstrap program loaded from ROM.

 2. Bootstrap runs the POST.

 3. Bootstrap locates IOS in Flash.

4. IOS is expanded and then loaded into RAM .

5. Once IOS is loaded into RAM, it looks for startup-config in NVRAM .

6. If found, the configuration is loaded into RAM .

ROUTER MODES :-

there are six mode in router but mainly used of them three modes.

1. User- mode.: Automatically enter this mode when router is turned on You can perform basic tasks, such as connect to remote devices, perform basic tests  .
    ,Prompt :is as  Router>.

   

   fig .user mode

2. Privileged Mode.: High-level testing commands Set operating parameters Command to enter : Router>enable  ,then show as  Prompt : Router#.

   

   fig- privilige  mode

   
                                                                     or
   By this mode we can check every configuration of router ,erase,reboot etc.
3. Global configuration mode :-  Commands apply to features that affect the system as a whole Enter from privileged EXEC mode with command :
   Router#config t,  Prompt : Router(config)# 

   

   fig- config mode

4.  Interface mode :-  Configure interface, such as Ethernet, serial Enter from global configuration mode with command : Router(config)#int e 0/0  Or Router(config)#int s 0/0 Prompt : Router(config-if)#
5. Rommon mode :-Provides router with a small subset of IOS and helps router boot if IOS not found in Flash Prompt : Rommon 1>
6. Setup mode :-Helps new user to create a configuration for the first time, via a series of questions Prompted at bootup or enter setup at
   router# prompt

ROUTER BASICS

Router Basics : Mode and Interfaces.

There are two types of components in router .

1. external components:

(a).  serial port:- Router to router connectivity.

(b).External port:_- lan connectivity.

(c). AUI:- Additional lan port.

(d). AUX:- Wan connectivity through modem.

(e). Consol port:- To confiqure the router/switch from another computer.

Internal component;-

(a). Motherboard:- Gives a plateform to connect all device.

(b). ROM:- it is stand for Read Only Memory .it is used to read and write data.

(c). RAM:- It is a volatile memory .it hold only active configuration & running configuration of router. it  hold routing table & Arp table.

(d). NV-RAM:- It is non-volatile memory,which is startup configuration.

Flash Memory:- It conten's IOS of router.

Mini IOS:- it provides to installed IOS of router,whome IOS is not present in flash memory.

configuration resister value in router:-

It is 16 bit value which is represented in hexadecimal formate that fells the router form whoes it will boot.

there are four types of resister value.

(1). 0x2100 tell the router to boot from rom monitor mode (safe mode).

 (2). 0x2101:- To boot from mini ios.

(3). 0x2102:- to boot from flash with nvram/startup confiquration. it is default configuration resister value.

(4). 0x2142:- Boot from flash ,but ignore nvram configuration.

Flow chart of Router/Boot sequence :

1. POST.:

 2. Boot Strap:

 3. Flash:

4. NVRAM:

5.RAM:

VLSM(Variable Length Subnet Mask )

 Variable Length Subnet Mask :

                                                     Neither RIPv1 nor IGRP routing protocols have a field for subnet information, so the subnet information gets dropped. What this means is that if a router running RIP has a subnet mask of a certain value, it assumes that all interfaces within the classful address space have the same subnet mask. This is called classful routing, and RIP and IGRP are both considered classful routing protocols. Classless routing protocols, however, do support the advertisement of subnet information. Therefore, you can use VLSM with routing protocols such as RIPv2, EIGRP, and OSPF. The benefit of this type of network is that you save a bunch of IP address space with it.

 VLSM  enables you to have more than one mask for a given class of address, albeit a class A, B, or C network number.

VLSM, originally defined in RFC 1812, allows you to apply different subnet masks to the same class address space Classful protocols, such as RIPv1 and IGRP, do not support VLSM. To deploy VLSM requires a routing protocol that is classless—BGP, EIGRP, IS-IS, OSPF, or RIPv2, for instance. VLSM provides Two major advantages.

1     .more efficient use of addressing .

2.      Ability to perform route summarization when you perform classfulsubnetting, all subnets have the same number of hosts because they all use the same subnet mask. This leads to inefficiencies. For example, if you borrow 4 bits on a Class C network, you end up with 14 valid subnets of 14 valid hosts. A serial link to another router only needs 2 hosts, but with classical subnetting, you end up wasting 12 of those hosts. Even with the ability to use NAT and private addresses, where you should never run out of addresses in a network design, you still want to ensure that the IP plan that you create is as efficient as possible. An efficient addressing scheme using VLSM.

3. Find the largest segment in the area—the segment with the largest number of devices connected to it.

4. Find the appropriate subnet mask for the largest network segment.

5.  Write down your subnet numbers to fit your subnet mask.

6. For your smaller segments, take one of these newly created subnets and apply a different, more appropriate, subnet mask to it.

7. Write down your newly subnetted subnets.

8. For even smaller segments, go back to step 4.

Route Summarization :

Route summarization is the ability to take a bunch of contiguous network numbers in your routing table and advertise these contiguous routes as a single summarized route. Route summarization, or supernetting, is needed to reduce the number of routes that a router advertises to its neighbor. Remember that for every route you advertise, the size of your update grows. It has been said that if there were no route summarization, the Internet backbone would have warped from the total size of its own routing tables back in 1997. Routing updates, whether done with a distance vector or link-state protocol, grow with the number of routes you need to advertise. In simple terms, a router that needs to advertise ten routes needs ten specific lines in its update packet. The more routes you have to advertise, the bigger the packet. Thebigger the packet, the more bandwidth the update takes, reducing the bandwidth available to transfer data. But with route summarization, you can advertise many routes with only one line in an update packet. This reduces the size of the update, allowing you more bandwidth for data transfer. Summarization allows you to create a more efficient routing environment by providing the following advantages:

1. It reduces the size of routing tables, requiring less memory and processing.

2. It reduces the size of updates, requiring less bandwidth.

3. It contains network problems 

 Example of VLSM  :

 

SEGMENT,FRAME AND PACKET

What is a Frame?

Frame is the name used to represent the Protocol Data Unit(PDU) at one of the lowest level in the reference model. Its the PDU at data link layer. Any communication between two computers or two networking devices is always done using MAC addresses. MAC addresses are nothing but physical addresses associated with the network interface card.

If you want to deliver a message to another machine on a network, it will first search for the physical address of the destination. There is actually something called as ARP, that does the job of translating IP addresses to Physical addresses. ARP(address resolution protocol) is one of the core components in networking.

 Every operating system with networking capability, has this feature called ARP. It does the job of maintaining a mapping between ip addresses and corresponding MAC addresses(Physical address).

PDU of Transport layer is called as a “Segment”, PDU of network layer is called as a “Packet” & PDU of data link layer is called as a “Frame”.

What is segment:?

So applications provide byte stream to TCP, and TCP takes care of creating it into discrete pieces of messages. These discrete pieces of messages at Transport Layer(where TCP comes into picture) are called "Segments".

What is packets?

The Segment (which includes data chunk and its headers) are then passed down from Transport layer to the next layer called Network Layer. Here is where IP addresses steps in. I think out of all three(Segments, Packets & Frames), packets are something that's mostly correctly used in different places. As packets are discrete messages in Network Layer which has IP addresses, they are sometimes referred to as "IP packets".

NOTE:-  A "segment" which is now sitting inside a "packet", is now passed down to the next layer called data link layer. Data link layer will add its own control and functional fields on top of the packet(called headers) to make something called as a "frame".

 

 

SEGMENT	Packet	frame
PDU at transport layer.	PDU at network layer.	PDU at Data-link layer.
Port numbers are part of Segments	IP addresses are part of a Packet	Mac addresses are part of Frames