| Layer | Protocol |
| Application | HTTP, POP3, SMTP |
| Transport | TCP, UDP |
| Internet | IP, IPv6 |
| Data-Link | MAC |
| Physical | Ethernet, PPP, T/1 |
TCP/IP Model and Associated Protocols
May 19, 2013
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Networking, Protocols, TCP/IP Model | Tagged: application, ccent, ccna, dat-link, ethernet, hhtp, internet, ip, ipv6, mac, mac address, physical, pop3, ppp, protocols, smtp, t/1, TCP, tcpip, transport, UDP | 
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Posted by Josh Gahan
Port Security
April 28, 2013Switches examine the source MAC address of the received frame, switches can take a few possible options if it discovers that the incoming MAC address on that port is NOT SECURE.
- shutdown (the switch shuts down the port and sends a log message and drops the frame/s , also the interface status will read err-disabled you have to run a no shutdown to open the port again) ON BY DEFAULT
- restrict (drops the frames and transmits a log message but does not shutdown the port)
- protect (only drops the frames)
When configuring Port security and the source MAC address is unknown switchport port-security mac-address sticky can be used and the switch will use the first mac address learned as the Secure MAC address
Leave a Comment » | Networking, Security, Switches | Tagged: advice, ccent, ccent exam, ccna, ccna exam, cent, cisco, cisco hardware, cisco ios, cisco switches, cisco switching, did you know, err-disabled, hints n tips, information technology, iOS, ios commands, it, it security, mac, mac address, networking, packet, port security, protocol, router, security, switches, TCP, transmission control protocol, UDP | Permalink
Posted by Josh Gahan
Spanning Tree Protocol (STP)
April 27, 2013Switching loops form when multiple paths exist, when a frame is sent and the the frame travels between the switches and never ends up reaching it’s final destination.
STP is used to prevent switching loops and is on by default, it determines a loop free path and ports that are not on the path are put into a blocking mode. If the best path is no longer available STP will calculate a new “path” and ports on that path that where blocked are brought out of the blocking mode.
NB. the shortest physical path is not the best, STP looks at the speed of the links
STP Quick Overview
- On by default
- Used to prevent switching loops
Leave a Comment » | Networking, Protocols, Switches | Tagged: blocking mode, ccent, ccent exam, ccna, ccna exam, cisco switches, default, l2pdu, networking, packet, router, security, segmentation, spanning tree, spanning tree protocol, stp, switch protocols, TCP, technology, UDP | Permalink
Posted by Josh Gahan
CSMA/CD – Collision Sense Multiple Access / Collision Detection
April 25, 2013All you need to know about the CSMA/CD process
- Transmitting host will listen, if silent data transmission commences
- If a voltage change is observed, (this is the collision) both hosts will send a jam signal
- This starts a random backoff algorithm, and once the random time has elapsed the host will commence transmission again by listening to the wire.
Leave a Comment » | Networking, Troubleshoot | Tagged: ccent, ccent exam, ccna exam, cisco, cisco switches, csma/cd, error, hints n tips, host, labs, listening, networking, node, packets, study, switches, TCP, UDP, voltage | Permalink
Posted by Josh Gahan
DHCP & DORA
April 24, 2013DHCP will supply the following 4 pieces of information
- IP address
- Default Gateway
- DNS Server
- Subnet Information
DHCP Process (DORA)
- Discover
- Offer
- Request
- Acknowledgement
Leave a Comment » | Networking, Protocols | Tagged: acknowledge, advice, ccent, ccent exam, ccna, ccna exam, cisco, cisco switches, dhcp, did you know, discover, dora, hints n tips, networking, offer, request, router, stub network, study, switches, TCP, UDP | Permalink
Posted by Josh Gahan
Common Ports For CCENT/CCNA Exam
October 14, 2012The following is not an exhaustive list but from all the texts that i have read these are the most common that you will need to know when taking the Cisco Exams
| Protocol | TCP/UDP | Number |
| FTP Data | TCP | 20 |
| FTP Control | TCP | 21 |
| SSH | TCP | 22 |
| Telnet | TCP | 23 |
| SMTP | TCP | 25 |
| HTTP | TCP | 80 |
| POP3 | TCP | 110 |
| SSL | TCP | 443 |
| DHCP | UDP | 67,68 |
| TFTP | UDP | 69 |
| SNMP | UDP | 161 |
| DNS | TCP/UDP | 53 |
VOIP Range: UDP Ports 16384 – 32767 are used for voice
I have also attached a few copies of the information provided PDF and Microsoft Word DOC
Leave a Comment » | Networking, Protocols | Tagged: ccna, cent, port numbers, ports, TCP, UDP | Permalink
Posted by Josh Gahan
TCP/UDP Similarities
October 12, 2012The Similarities Are..
- Source Port
- Destination Port
- Checksum
and that’s it!
Leave a Comment » | Networking, Protocols, Transport Layer | Tagged: networking, TCP, transmission control protocol, UDP, user datagram protocol | Permalink
Posted by Josh Gahan
TCP and UDP Summary
October 12, 2012TCP (Transmission Control Protocol)
- Connection orientated
- Provides Windowing (Flow Control)
- Error detection using sequence and Acknowledgment numbers
- Error recovery
UDP (User Datagram Protocol)
- Best effort delivery
- Zero error “detection”
- Zero windowing capabilities
- Connectionless
NB.
TCP uses a three way handshake to establish the connection with the remote host, while UDP does not, this is why TCP is referred to as a connection orientated protocol
Leave a Comment » | Networking, Protocols, Transport Layer | Tagged: connection orientated, connectionless, protocol, TCP, three way handshake, transmission control protocol, transport layer, UDP, user datagram protocol | Permalink
Posted by Josh Gahan