After get understanding on E1 Carier System, Frame Relay is part of the related topic which play a big role on E1 Careir System

Frame Relay is a simplified form of connection-based, packet-switching service in which synchronous frames of data are routed to destinations indicated on the header information. Frame Relay assumes an error-free physical link and therefore does not guarantee data integrity. Error detection and correction responsibility is left with the end devices.

Frame Relay uses the synchronous High-level Data Link Control (HDLC) frame format up to 4096 octets in length. Each frame contains a start flag, two octets that contain the information required for multiplexing across the link, the data information (payload), two octets generated by a cyclic redundancy check (CRC) of the rest of the octets between the flags, and the end flag.

Permanent virtual circuits (PVCs) are used to form a connection between any two devices attached to a Frame Relay cloud. Virtual circuits are logical, bidirectional, end-to-end connections that appear to the user as dedicated links. Each PVC is given a unique number on each physical circuit along the path between the two devices. (more…)

Posted by calvyn | 1 Comment »

While study on the radio system during my working hour, found that the system here are using normal Ethernet cable to connect the main system  to the Base Station. Normally an Ethernet cable maximum transmission distance are not recommended to be more the  100 Meter.

According to the senior engineer over there, if the base station located far away from the main system, they normally using fiber optic or some other medium such as wireless, antenna in special frequencies or E1 line from ISP.

An E1 carrier is a telecommunications facility designed to carry digital information at a bit rate of 2.048 Mbps. In conventional telecommunications, the most common use for an E1 carrier is to connect central offices within an individual telephone company. Telephone companies also lease E1 carriers to their customers for their own private purposes. Most systems use E1 circuits to transmit digitized voice, management, and control traffic between zones. The Frame Relay and Cell Relay protocols provide the means for exchanging information over the E1 communication facilities that connect remote zones.

Various types of transmission media can be used in implementing a private E1 facility, (more…)

Posted by calvyn | 5 Comments »

Access Network, (AN) is made by the international community in recent years (2006), a new concept, which includes subscriber line transmission system, MUX, but also including digital cross-connect equipment, and user / network interface device. In the ITU-T Study Group No. 13, the latest recommendations G.963, the access network is defined as the local exchange (LE) and customer premise equipment (TE) between the implementation of the system with the aim of considering the local exchange, the user ring Road and terminal equipment, through the standardization of interfaces will be limited demand for a variety of user access nodes. Access to the communications network of the introduction of new changes in the structure of the entire communications network, fundamental changes have taken place. (more…)

Posted by calvyn | 6 Comments »

During the 1st week at Motorola, I need to hv some basic study again which related to this field. When I come across this topic “type of communication” just recall back on my academic study on “Communication Network“, almost the same, just that here, I can get know more detail which does not include in my study.

Radio systems use any of three types of communication: simplex, semi-duplex, and full-duplex. The communication type used depends on the number of users and the type of equipment available. This section provides a description of the three types of communication.

Simplex Communication
The most basic type of radio communication is simplex. Simplex communication consists of radio units operating on a single frequency. Because everyone transmits and receives on the same frequency, users cannot talk and listen at the same time. Simplex means transmission in one direction at a time.

A simplex radio system works well when there are only a few users who are closely located. When additional users are added to the system, the competition for the one available frequency can make it difficult to get a message across. In addition, great distances and natural obstacles such as high hills and tall buildings can interfere with the single frequency.

Do you know: Television Channel and Radio Channel (FM or AM) are (more…)

Posted by calvyn | 11 Comments »

While a network administrator forgot the password over the cisco router or switch, you need to reset password for cisco router or recover password for cisco router, this is a common mistaken for a Network Administrator, always forgot the password if long time did not do configuration for the cisco router. how to reset cisco router password? if you forgot the password to login cisco router?

Router>enable
Password:
Password:
Password:
% Bad secrets

Router>show version
Cisco IOS Software, 2800 Software (C2800NM-ADVIPSERVICESK9-M), Version 12.4(15)T1, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Wed 18-Jul-07 06:21 by pt_rel_team

ROM: System Bootstrap, Version 12.1(3r)T2, RELEASE SOFTWARE (fc1)
Copyright (c) 2000 by cisco Systems, Inc.

System returned to ROM by power-on
System image file is “c2800nm-advipservicesk9-mz.124-15.T1.bin”

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

cisco 2811 (MPC860) processor (revision 0×200) with 60416K/5120K bytes of memory
Processor board ID JAD05190MTZ (4292891495)
M860 processor: part number 0, mask 49
2 FastEthernet/IEEE 802.3 interface(s)
239K bytes of NVRAM.
62720K bytes of processor board System flash (Read/Write)

Configuration register is 0×2102

Router>

Just remember the current cisco router register number “2102“, after that, on and off your cisco router, press crtl + backspace + break to enter the NVram (more…)

Posted by calvyn | 14 Comments »