	Home

	MCSE

	MCSE + Security

	CCNA

	CCNP

	Schedule

	Register

	Frequently Asked Questions

	Course Fees

	Contact US

	Boot Camp Location

	Compare us to our competitors

	Testimonials

	Sitemap

JOIN THE BEST MCITP Boot Camp, MCSE Boot Camp also CCNA , CCNP Certification Boot Camp Training program. 100% Guaranteed - Lowest Fees, Highest Passing Rate. MCSE Boot Camp Certification

MCITP MCSE and CCNA Certification Notes Series :

MCSE 2016 Boot Camp : Azure Boot camp : CCNA / CCNAX Boot Camp:

CCNA Boot Camp

Cisco Hierarchical Model:
For more information about this, please read our separate tutorial titled "The Cisco Hierarchical Model".

OSI Model:
The OSI model is a layered model and a conceptual standard used for defining standards to promote multi-vendor integration as well as maintain constant interfaces and isolate changes of implementation to a single layer. It is NOT application or protocol specific. In order to pass any Cisco exam, you need to know the OSI model inside and out.

The OSI Model consists of 7 layers as follows:

Layer	Description	Device	Protocol
Application	Provides network access for applications, flow control and error recovery. Provides communications services to applications by identifying and establishing the availability of other computers as well as to determine if sufficient resources exist for communication purposes.	Gateway	NCP, SMB, SMTP, FTP, SNMP, Telnet, Appletalk
Presentation	Performs protocol conversion, encryption and data compression	Gateway and redirectors	NCP, AFP, TDI
Session	Allows 2 applications to communicate over a network by opening a session and synchronizing the involved computers. Handles connection establishment, data transfer and connection release	Gateway	NetBios
Transport	Repackages messages into smaller formats, provides error free delivery and error handling functions	Gateway	NetBEUI, TCP, SPX, and NWLink
Network	Handles addressing, translates logical addresses and names to physical addresses, routing and traffic management.	Router and brouter	IP, IPX, NWLink, NetBEUI
**Data Link	Packages raw bits into frames making it transmitable across a network link and includes a cyclical redundancy check(CRC). It consists of the LLC sublayer and the MAC sublayer. The MAC sublayer is important to remember, as it is responsible for appending the MAC address of the next hop to the frame header. On the contrary, LLC sublayer uses Destination Service Access Points and Source Service Access Points to create links for the MAC sublayers.	Switch, bridge and brouter	None
Physical	Physical layer works with the physical media for transmitting and receiving data bits via certain encoding schemes. It also includes specifications for certain mechanical connection features, such as the adaptor connector.	Multiplexer and repeater	None

Here is an easy way to memorize the order of the layers:
All People Seem To Need Data Processing. The first letter of each word corresponds to the first letter of one of the layers. It is a little corny, but it works.

Class	Range	Explanation
A	1-126	IP addresses can be class A, B or C. Class A addresses are for networks with a large number of hosts. The first octet is the netid and the 3 remaining octets are the hostid. Class B addresses are used in medium to large networks with the first 2 octets making up the netid and the remaining 2 are the hostid. A class C is for smaller networks with the first 3 octets making up the netid and the last octet comprising the hostid. The later two classes aren’t used for networks.
B	128-191
C	192-223
D	224-239 (Multicasting)
E	240-255 (Experimental)

A subnet mask blocks out a portion of an IP address and is used to differentiate between the hostid and netid. The default subnet masks are as follows:

Class	Default Subnet	# of Subnets	# of Hosts Per Subnet
Class A	255.0.0.0	126	16,777,214
Class B	255.255.0.0	16,384	65,534
Class C	255.255.255.0	2,097,152	254

In these cases, the part of the IP address blocked out by 255 is the Net ID.

3COM’s IP addressing tutorial is just superior. It covers basic IP addressing options as well as subnetting and VLSM/CIDR.

IPX/SPX:
IPX will also be an important issue to consider in network management given the fact there many companies still use Netware servers. There are two parts to every IPX Network address - the Network ID and the Host ID. The first 8 hex digits represent the network ID, while the remaining hex digits represent the host ID, which is most likely the same as the MAC address, meaning we do not need to manually assign node addresses. Note that valid hexadecimal digits range from 0 through 9, and hexadecimal letters range from A through F. FFFFFFFF in hexadecimal notation = 4292967295 in decimal.

Sequenced Packet Exchange(SPX) belongs to the Transport layer, and is connection-oriented. It creates virtual circuits between hosts, and that each host is given a connection ID in the SPX header for identifying the connection. Service Advertisement Protocol(SAP) is used by NetWare servers to advertise network services via broadcast at an interval of every 60 minutes by default.

Ethernet Frames

Ethernet was developed by the Xerox Corporation's Palo Alto Research Center (PARC) in the 1970s. Ethernet was the technological basis for the IEEE 802.3 specification, which was initially released in 1980. Shortly thereafter, DEC, Intel, and Xerox jointly developed and released and Ethernet specification (Version 2.0) that is substantially compatible with IEEE 802.3. Today, the term Ethernet is often used to refer to all CSMA/CD LANs that generally conform to Ethernet specification, including 802.3.

Ethernet Frames

Used at the Data Link layer to encapsulate packets handed down from the Network layer for transmission on a medium.
Ethernet_II frames have a type field in their frame.
802.3 frames have a length field in their frame.
Data size can be from 46 to 1500 bytes.
FCS - Frame Check Sequence - used to store the CRC (Cyclic Redundancy Check) for the frame.
802.3 frame can't contain information about the upper layer protocols (Network Layer), so it is combined with the 802.2 (LLC) frame to provide this function.

The Four Types of Ethernet Frames:

Ethernet II
IEEE 802.3
IEEE 802.2
SNAP

Ethernet II

Ethernet provides services corresponding to Layers 1 and 2 of the OSI model. In Ethernet frames, the 2-byte field following the source address is a type field. This field specifies the upper-layer protocol to receive the data after Ethernet processing is complete. Ethernet is a broadcast LAN that uses CSMA/CD.

IEEE 802.3

IEEE 802.3 specifies the Physical layer (Layer 1) and the channel access portion of the Data Link layer (Layer 2), but doesn't define a logical link control protocol. In IEEE 802.3 frames, the 2-byte field following the source address is a length field, which indicates the number of bytes of data that follows this field and precede the frame check sequence (FCS) field. Following this is the data field, which will contain data for the frame. In the case of IEEE 802.3, the upper-layer protocol must be defined within the data portion of the frame. IEEE 802.3 is also a broadcast LAN that uses CSMA/CD.

IEEE 802.2

IEEE 802.2 is often referred to as the Logical Link Control (LLC). It is extremely popular in LAN environments, where it interoperates with protocols such as IEEE 802.3, IEEE 802.4, and IEEE 802.5. Upper-layer processes use IEEE 802.2 services through service access points (SAPs). The IEEE 802.2 header begins with a destination service access point (DSAP) field, which identifies the receiving upper-layer process. Following the DSAP address is the source service access point (SSAP) address, which identifies the sending upper-layer process.

802.2 SNAP

The SNAP (Subnetwork Architecture Protocol) frame has its own protocol field to identify the upper-layer protocol. This is a way to allow an Ethernet II frame to be used in an 802.3 frame. SNAP frame's DSAP and SSAP are always set to AA with the command field set to 3. SNAP was created because not all protocols worked well with the 802.3 frame which has no ether-type field. 802.2 frame is an 802.3 frame with the LLC info in the data field of the header (has DSAP and SSAP). To allow the proprietary protocols created by application developers to be used in the LLC frame, the IEEE defined the SNAP format. SNAP is mostly seen with proprietary protocols such as Appletalk and the Cisco CDP.

MAC Addressing

48-bit address.
Manufacturer's identification (OUI- Organizationally Unique Identifier) is the first 24-bits and is assigned by the IEEE.
Manufacturer assigns a unique value to the second 24-bit section

Function of a MAC address

The MAC address uniquely identifies the device from any other device in the world.
The MAC address is a 48 bit address represented by 12 hexadecimal digits.
The first 6 digits contain the manufacturer's Unique identifier (OUI) and the last 6 digits are the unique serial number assigned by the manufacturer.
The MAC Address is usually burned onto a NIC (Network Interface Card) in its ROM (Read Only Memory).

MAC Address Examples

MAC Address	Manufacturer Code	Serial Number
FF34.2344.13FD	FF34.23	44.13FD
44CC.7800.34FF	44CC.78	00.34FF
00A0.CC60.1388	00A0.CC	60.1388

3 Types of Media Access

Contention (Ethernet)
Token Passing (Token Ring, FDDI)
Polling (IBM Mainframes, 100VGAnyLAN)

Ethernet

Uses a logical bus topology - signal runs from one end of the segment to the other.
Baseband technology - when a station transmits, it uses the entire bandwidth.
Uses CSMA/CD.
Best effort delivery.

Each of the 802.3 (Ethernet) standards defines an AUI

10BaseT - uses AUI - 1 bit at a time
100BaseT - uses MII - 4 bits at a time
1000BaseT - uses GMII - 8 bits at a time

AUI - Attachment Unit Interface

MII - Media Independent Interface

GMII - Gigabit Media Independent Interface

Call Now : 800-519- 2267

Why Vibrant Boot camp

No Prestudy

Longest Duration Bootcamp

Chalk Talk Training

Highest Passing Rate

Bootcamp since 1997

Guaranteed Lowest Rate

Guaranteed Certification ...

Testimonials

If you're serious about getting certified, this is the place to go. Definitely worth their competitive price. Excellent instructors, making it possible for anyone to learn no matter what your level of experience or knowledge.

Michael Doty

MCITP MCSE CCNA CCNP Boot Camp

Ethernet Frames

Ethernet Frames

The Four Types of Ethernet Frames:

MAC Addressing

3 Types of Media Access

Ethernet