G K Reddy Chinthalapudi

Many times we save lot of time if we automate things. Assume you want to put a fine named abcd.doc in server named www.myserver.com. We will do as follows in terminal/command prompt ftp www.myserver.com Then it will ask for USERNAME and PASSWORD, if we enters correctly FTP session for us opened successfully. Then we can use ftp commands to put/get files to/from www.myserver.com. For putting abcd.doc we will use command put as follows ftp>put abcd.doc Then we will use bye to exit ftp session ftp>bye Automating above session through shell script Assume user name is usermane and password password for logging into system www.myserver.com user username password put abcd.doc close bue SCRIPT exit 0 You can use IP address also instead of server name.

Many times we save lot of time if we automate things. Assume you want to put a fine named abcd.doc in server named www.myserver.com We will do as follows in terminal/command prompt ftp www.myserver.com Then it will ask for USERNAME and PASSWORD, if we enters correctly FTP session for us opened successfully. Then we can use ftp commands to put/get files to/from www.myserver.com. For putting abcd.doc we will use command put as follows ftp>put abcd.doc Then we will use bye to exit ftp session ftp>bye Automating this session Assume user name is usermane and password is password for logging into system www.myserver.com ftp -n www.myserver.com <

Layer 2 Functionalities Framing Error detection & Correction Multiplexing Flow Controller Framing Issues LAPD uses HDLC frame format for framing. Where as LAPDm uses synchronization scheme of radio interface to convey information on frame limits. LAPDm avoids using flags by ready-made blocks of the physical layer. LAPDm(LAPD modified) frame has a maximum length of 23 octets on all TCH channels and 21 octets on SACCH blocks(remaining 2 octets are for Timing Advance and Transmission Power Control). But the actual frame length is less than 23/21 octets, so Length Indicator(LI) is included in each frame to identify the length of the frame. Segmentation & Reassembly There is no need of segmentation & Reassembly in LAPD(the length of the Abis LAPD frame is 264 octets excluding flags, which corresponds to 260 octets of upper layer information). Where as LAPD requires segmentation& reassembly because maximum frame length of 21 or 23 octets is not sufficient for most signalling

Layer 2 Functionalities Framing Error detection & Correction Multiplexing Flow Controller Framing Issues LAPD uses HDLC frame format for framing. Where as LAPDm uses synchronization scheme of radio interface to convey information on frame limits. LAPDm avoids using flags by ready-made blocks of the physical layer. LAPDm(LAPD modified) frame has a maximum length of 23 octets on all TCH channels and 21 octets on SACCH blocks(remaining 2 octets are for Timing Advance and Transmission Power Control). But the actual frame length is less than 23/21 octets, so Length Indicator(LI) is included in each frame to identify the length of the frame. Segmentation & Reassembly There is no need of segmentation & Reassembly in LAPD(the length of the Abis LAPD frame is 264 octets excluding flags, which corresponds to 260 octets of upper layer information). Where as LAPD requires segmentation& reassembly because maximum frame length of 21 or 23 octets is not sufficient for most signalling