How to Email “exe” file
August 16, 2011 in Uncategorized by justice3
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by ciscoguy
CCNA Vocabulary 1
August 12, 2011 in CCNA by ciscoguy
Below is list of terms you need to know for the CCNA exam.
| Access Link | The serial link (physical) that connects a Frame Relay device (such as a router) to a Frame Relay switch |
| Back-to-Back Link | A serial link connecting two routers without CSU/DSUs. One router used a DTE cable and the other uses a DCE cable. Typically used in labs. |
| CSU/DSU | Channel Service Unit/Digital Service Unit. A device that knows how to use the layer 1 details of telco Layer 1 serial links that connect to devices such as routers. |
| DTE | Data Terminal Equipment. The DTE synchronizes its clock based on the DCE clock. (Layer 1). Otherwise it is a device not within the service provider’s network (like a routher). |
| DS0 | Digital Signal Level 0. 64Kbps line from the telco. Used for single voice calls. |
| DS1 | Digital Signal Level 1. 1.544Mbps line inside a telco. Uses 24 DSO channels of its original speed plus a management/framing channel of 8Kbps. Also known as a T1. |
| Frame Relay | A standard data-link protocol to create frame-switched or packet-switched service that uses DTE devices (such as routers) to connect to other devices using one physical connection. |
| HDLC | High-level Data Link Control. Data-link layer protocol. |
| Packet Switching | Term used to reference services that examine the contents of data to make forwarding decisions. |
| T1 | 1.544Mbps line inside a telco. Uses 24 DSO channels of its original speed plus a management/framing channel of 8Kbps. Also known as DS1. |
| PDU | OSI Protocol Data Unit. This includes headers and trailers for the current layer and all the encapsulated data, if any. Often used as L#PDU. For example, L2PDU references the Data Link layer data unit. |
by ciscoguy
OSI Model
August 12, 2011 in CCNA by ciscoguy
| OSI Layer | Description |
|---|---|
| Application | User authentication, software communication |
| Presentation | Determines data formats and encryption (ie: JPG, ASCII) |
| Session | Defines how to start, end and control conversations |
| Transport | Error recovery, data delivery, flow control |
| Network | Logical addressing, routing, path determination |
| Data Link | Defines rules/protocols for when devices can send its data over mediums and defines format of headers and trailers |
| Physical | Cables, lights, electricity, etc. |
| OSI Layer | Protocol/Specs | Devices |
|---|---|---|
| Application/Presentation/Session | Telnet, FTP, HTTP, VoIP, POP3, SMTP | IDS, Firewall |
| Transport | TCP, UDP | |
| Network | IP | Router |
| Data Link | HDLC, PPP, IEEE, Frame Relay | WAP, Switch, Modem |
| Physical | RJ-45, IEEE | Hub, Repeater |
by ciscoguy
Common Applications & their Port Numbers
August 12, 2011 in CCNA by ciscoguy
This is a list of common applications and port numbers you need to know for the CCNA exam.
| Common Applications & their Port Numbers |
||
|---|---|---|
| 23 | TCP | Telnet |
| 25 | TCP | SMTP |
| 53 | TCP, UDP | DNS |
| 67,68 | UDP | DHCP |
| 69 | UDP | TFTP |
| 80 | TCP | HTTP |
| 110 | TCP | POP3 |
| 161 | UDP | SNMP |
| 443 | TCP | SSL |
| 14,384-32,767 | UDP | VoIP |
Misc:
TCP: Transmission Control Protocol
UDP: User Datagram Protocol