Albert’s CCNA Study Guide(1)
添加时间: 2007-9-8 2:56:46 作者: Cisco认证考试 阅读次数:57 来源: http://www.d9soft.com
Access list
1-99 IP standard
100-199 IP extended
200-299 Protocol type code
300-399 DECnet access list
400-499 XNS Standard Access
500-599 XNS Extended Access
600-699 AppleTalk
700-799 48 bit MAC address
800-899 IPX
900-999 IPX Extended
1000-1099 IPX SAP
1100-1199 Extended 48 bit MAC address
1200-1299 IPX summary address
Port numbers
TCP=6
UDP=17
FTP=21
TELNET=23
SMTP=25
DNS=53
TFTP=69
SNMP=161
NOVEL IPX Frame Type
Interface
Novell Frame Type
Cisco Keyword
Ethernet
Ethernet 802.3 and NetWare 3.11
Novell Ether
IPX Ethernet Encapsulation
Ethernet 802.2 and NetWare 3.12
SAP
Ethernet II
ARPA, DECnet and supports TCP/IP, IPX and upper layers
Ethernet SNAP
SNAP, AppleTalk, IPX, and TCP/IP
Token Ring
Token Ring 802.
SAP
Token Ring_SNAP
SNAP
FDDI
FDDI SNAP
SNAP
FDDI 802.2
SAP
FDDI RAW
NOVELL-FDDI
DOD model
IP
DOD
Protocol
Application, Presentation, Session
Process Application
Telnet, FTP, LPD, SNMP, TFTP, SMTP, NFS, X WINDOW
Transport
Host to Host
TCP, UDP
Network
Internet
ICMP, BOOTP, ARP, RARP, IP
Data Link
Network Access
Ethernet, Fast Ethernet, Token Ring, FDDI
IPX Protocl Stack:
Application, Presentation, Session ?/span> RIP, SAP, NCP, NLSP, etc…
Transport ?/span> IPX, SPX
Network ?/span> IPX
Data link ?/span> ODL Open Data Link
Physical ?/span> whatever
OSI Model:
Transport is TCP Segments
Network is IP Packets/Datagrams
Data Link is Ethernet frames
Physical is Bits
The five steps to Encapsulation:
1. Build the data
2. Package data for end-to-end transport (Segments transport subsystem)
3. Append network address in header (data is put into a packet or datagram) Network
4. Append local address in data link header (must be put into a frame or packet) Data
5. Convert to bits for transmission 1 and 0 Physical
Data > Segment > Packet > Frame > Bits
Data Encapsulation Method
1. User information is converted to data for transmission on the network.
2. Data is converted to segments and packaged with control information for a reliable connection.
3. Segments are encapsulated with a network header and converted to packets or datagrams, which specify the source and destination logical addresses.
4. Packets, or datagrams, are converted to frames to allow a connection over an interface to the network.
5. Frames are converted to bits with some clocking functions to allow transmission a medium.
Key Terms:
Bits: The Physical layer takes the binary data down from the Data Link Layer and converts the 1's and 0's to a digital signal to be sent out over the physical topological.
Frames: These house the packets, or datagrams, handled down from the Network layer to be delivered to a device on a LAN.
Packets: Sometimes called datagrams, these house the segments handed down the
Transport layer to be routed through an internetwork.
Segments: Defined at the Transport layer, these are part of a data stream that is handed down from the upper layers to be transmitted to a destination device.
Ethernet Frame:
Preamble, DA, SA, Type, Data, FCS
OSI Model:
Application layer 7File, print, message, database, and applications. Determines availability of the target host. www, email, ftp, telnet, EDI, quake
Presentation layer 6
Text and Data Formatting, Data Encryption, Compression, and Translation services Determines the syntax of the data transfer. Pict, tiff, jpeg, midi, mpeg, quicktime, EBCDIC and ASCII
Session layer 5
Service Requests, Dialog control, coordinates the communications, Establishes, Manages, and terminates communication sessions between applications. Offers full or half-duplex define and group formatted data, and offers some session recovery or checkpoint mechanisms between the applications coordinated between the hosts. NFS, SQL, RPC, X Windows, ASP (appletalk session protocol), DNA SCP (digital whatzit)
Transport layer 4
***TCP uses Three-way handshake for Transport test question***
End-to-end communication, flow control provided by sliding windows, and error checking
Ensure Data Reliability provided by sequence numbers and acknowledgements
NBP Name Binding Protocol it associates with AppleTalk
Responsible for hiding the communications from the higher layers. TCP / UDP
Segment upper layer applications
Establish end-to-end operations
Send segments from one end host to another end host using checksum
Ensure data reliability and uses SPX protocol
Multiplexing: refers to the capability of multiple applications to share a transport connection.
Note: When datagrams arrive to quickly for a host or gateway they are stored in memory temporarily. If the datagrams are part of a small burst, this buffering solves the problem. If the traffic continues, the host or gateway eventually exhausts its memory and must discard additional datagrams that arrive.
Network layer 3
Routing IP, ICMP, BootP, ARP, RARP Routers Logical Addressing and network Addressing
To enable path determination, the routing service provide:
- Routing table initialization and maintenance
- Routing update processes and protocols
- Routing domains and address specifications
- Route metric assignment and control
Test Question:
Routing protocols uses network topology information when evaluating network paths. This information can be configured by the network administrator or collected through DYNAMIC processes running in the network.
Data Link layer 2
Framing Ethernet II, 802.5 (token ring), 802.3, 802.2 (802.3 with dsap and sap logical link control fields) Media access control: MAC: 48 bits, 3 bytes vendor + 3 bytes serial number
WAN:
CDP, ( Cisco Discovery Protocol) High-level datalink control HDLC (Cisco default for serial links) Synchronous Data Link Control SDLC (uses polling) Link Access Procedure, Balanced LAPB x.25, slip, PPP, isdn, Frame Relay, and Dial on Demand
Bridges / Switches
Link Layer address
SAP and LLC is used to define the upper layers. Provides flow control.
The addresses for which the MAC sublayer is responsible.
Physical layer 1
Wire… v.24, v.35, x.21, g.703, hssi, etc
Repeaters / Hubs
100BaseFX is ethernet over fiber optic
100BaseTX is Ethernet over Category 5 and Type 1 cabling.
Hardware addresses are used to get a packet from one local device to another local device.
Logical Addressees are used to get a packet end to end through an internetwork.
Multicast address is a MAC address used to identify a group of destinations and is indicated by the first transmitted bit of the destination address being sent to 1.
Preamble: Both ethernet IEEE 802.3 frames begin with an alternating pattern of 1s and 0s. Simply tells the receiving stations that the frame is coming.
Routing Uses Network Addresses
Routers relay a packet from one data link to another. To relay a packet, a router uses two basic functions: a path determination function and a switching function.
Distance Vector Routing Protocol
Novel RIP (uses ticks and hops and SAPS)
EIGRP
RIP
IGRP
Classful Routing Protocols
IGRP, RIP
IGRP: Allows for unequal cost load balance
NON-Classful Routing Protocols
EIGRP, OSPF, AND NLSP
Routed Protocol
IP and IPX
Routing Protocols
TCP/IP, RIP, IGRP, OSPF, NLSP, Enhanced IGRP
- A routing protocol defines the set of rules used by a router when it communicates with neighboring routers.
Interior Routing Protocols
RIP, IGRP, Enhanced IGRP, OSPF, IS-IS (Immediate System to Intermediate System)
NLSPNovels link state routing protocol:
It will interoperate with RIP and SAP to ease the transaction and provide backward compatibility with RIP internetworks that have no need for link state routing.
Exterior Protocols
BGP, EGP
Routing Protocols
Distance Vector:Learns the best path destination networks based on accumulated metrics from each neighbor
Link State: Learns the exact topology of the entire internetwork. Maintains a complex of topology of information. Are used to create a common picture of the entire network. Uses neighboring notification.
Comparing Distance Vector Routing to Link State Routing
Distance Vector
Link State
Views net topology from neighbor perspective
Gets common view of entire network topology
Increments metrics as an updates: slow convergence
Calculates the shortest path to other routers
Frequent, periodic updates
Event triggered updates: faster convergence
Passes copies of routing table to neighbor routers
Passes link state routing updates to other routers
IP RIP updates occur every 30 seconds
IPX RIP updates occur every 60 seconds
SAP updates are sent every 60 seconds
Inverse ARP updates every 60 seconds
Frame Relay Serial CDP packet every 60 seconds
CDP hold time is 180 seconds
IGRP Sends regular routing update every 90 Seconds
IGRP Admin distance 100
RIP Admin distance 120
Update Timers 90 second updates
Hold-Down Timer 190 seconds
Protocols within an AS
OSPF
VLSM (Variable Length Subnet Mask)
EIGRP
IGRP 3 types of routes: (they use D-V and hop counts)
Interior
System
Exterior
**This was on my test for sure**
Protocol
Network Address
Node Address
Novell IPX
*********
32 bits; (hex) refers to the media (total 32+48=80 bits)
48 bits; (hex) usually the MAC address of a LAN interface
IP Address
32 bit mask
IP to MAC address
MAC Address
6 bytes and 48 bits
AppleTalk
16 bits (dec); refers to one or one to many nets in cable on media
8 bits added to network number; usually dynamically assigned on LAN
X.25 or X.121
4 (dec) digits of DNIC 2 or 3 digit data county code and I network digit
10 or 11 digits of network terminal number; usually assigned by Wan Service provider
Hw to setup an ISDN/PRI Interface on Cisco 7500
Isdn switch-type switch-type
Cisco LMI type:
Cisco
How many frame types are with Cisco Routers
Cisco
IETF
How many LMI types are available?
CISCO
ANSI
Q.933a
ISDN BRI Support:
Connect to lines with SPIDs (service Profile Identifiers) (phone numbers)
BRI: Basic Rate Interface:2 (64B) + 1 (16D)
B = 64kbs, D=16Kbps = 128kbs plus control
PRI: Primary Rate Interface: 23B + 1 (64D)
Total of 1.544Mbps
ISDN protocol codes:
E: existing telephone line
I: concepts, terms, and services
Q: switching and signaling and call setup and tear down
D Channel protocol carries signaling information (call setup) to control calls on B channels at the user network interface. Traffic over the D channel employs the LAPD data link level protocol. The D channel deals with physical, datalink, network, signaling and control
B Channel is a data channel (56k or 64K). It is used for digitized speech transmission or for relatively high speed data transport. Narrowband ISDN is circuit switched oriented. The B channel is the elemental circuit-switching unit.
ISDN Terminal Equipment Two basic types of equipment
TE1: Specialized ISDN terminal, including computer equipment or telephones. It is used to connect to ISDN through a four wire, twisted pair digital link.
TE2: NON ISDN terminal such as data terminal equipment (DTE) that predates the ISDN standards. A TE2 connects to ISDN through a terminal adapter (TA). An ISDN (TA) can be either a standalone device or a board inside the TE2.
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