Rays Systems

The main handicap is the greater packet overhead required by IP. Both FR and IP packets are constructed with packet header information, voice/fax header information, and the digitized, compressed voice and fax information (the payload). Each payload represents a fragment of speech called a ‘talk spurt.’ Representing a long talk spurt requires the VDID (Voice/Data Integration Device) to accumulate the speech information over an extended period of time, and possibly introducing delay into the conversation. Conversations with added delay sound unnatural and cause the corporate telephony user to bypass the VDN (Voice/Data Network), defeating any hoped-for cost savings. This delay-limiting requirement dictates a maximum talk spurt size for voice (and consequently, fax) of 50 bytes at a compressed data rate of 8Kbps (1000 bytes per second, or one byte per millisecond). Fifty bytes represent 50 milliseconds of speech activity, the longest practical period without contributing too much to the ...

There are four main areas of material differences between VoIP and VoFR packet management technologies: · Packet overhead · WAN access-line carrying capacities and associated cost implications · Packet prioritization · Packet segmentation or fragmentation and its effect on data packet sizes Each area of difference presents more of a challenge to the VoIP gateway approach than the VoFR approach, both because VoFR is more mature and because VoIP has a few inherent technological handicaps.

There are a several different types of wide area packet data networks that can support integrated voice/fax traffic, with varying degrees of success. The principal data network technologies in use today are X.25, Frame Relay, ATM, SNA, Novell/IPX, TDM, and TCP/IP. Because TDM is not a packet technology, it is much less efficient than the other technologies, and is rapidly being replaced by them. X.25 and SNA, based on older packet technologies, are too slow and delay-prone to effectively carry voice and fax traffic. The Novell/IPX technology was designed primarily for LAN applications and does poorly in the WAN environment; it is quickly being replaced by TCP/IP. The remaining packet technologies – Frame Relay, ATM, and TCP/IP – are the principal networking techniques companies use today to build new wide area data networks. Today’s WANs are constructed using leased lines running these three technologies, and using public data network services based on them. By a substantial margin, Fr...

Network Address Translation (NAT) • NAT is a router function where IP addresses (and possibly port numbers) of IP datagrams are replaced at the boundary of a private network • NAT is a method that enables hosts on private networks to communicate with hosts on the Internet • NAT is run on routers that connect private networks to the public Internet, to replace the IP address-port pair of an IP packet with another IP address-port pair.

Error Codes 1. #VALUE! – Wrong type of data. 2. #NAME? – Incorrect function name. 3. #NUM – Problem with one of the numbers you’re using. 4. #REF! – Incorrect cell reference. 5. ##### - Formula cannot be displayed in the cell using the current number format. Math and Statistical Functions 1. ROUND( number to round, #of digits) a) (3.987, 2) = 3.99 b) (3.987, 0) = 4 c) (34655.7, -2) = 34,700 2. ROUNDDOWN a) (1.1, 0) = 2 3. ROUNDDOWN a) (1.9, 0) = 1 4. MROUND (number to round, multiple) a) (653, 5) = 655 5. COUNT – Find out how many items there are in a list. 6. COUNTBLANK – Counts the number of empty cells in a specified range of cells. 7. RANK – Returns the rank of a number in a list of numbers: its size relative to the other values in the list. 8. REPT – Repeats text a given number of times. 9. SQRT – Returns the square root of a number. 10.STDEV – Estimates the standard deviation of a sample. 11.PERMUT – Returns the number of permutations for a given number of objects that can be sel...

AppInit_DLLs: All the DLLs that are specified in this value are loaded by each Microsoft Windows-based application that is running in the current log on session. The AppInit DLLs are loaded by using the LoadLibrary() function during the DLL_PROCESS_ATTACH process of User32.dll. Therefore, executables that do not link with User32.dll do not load the AppInit DLLs. Therefore one of the 16 imports was user32.dll (Import table (libraries: 16))Because of their early loading, only API functions that are exported from Kernel32.dll are safe to use in the initialization of the AppInit DLLs. So murka.dat registers itself in the "AppInit_DLLs" as a load point for the beep.sys so that every time the computer starts, the RootKit driver can load itself with the kernel... Example: Trojan.Virantix.B---------------------------------------------------------------------------------------------------------------------------------------------When the Trojan is executed, it creates following files...

SL: 138/6 (20.0 Ovs) Angelo Mathews * 35(24) Kumar Sangakkara 65(52) Pak Umar Gul * 4-0-30-1 Mohammad Aamer 4-1-30-1 RR : 6.90 Curr P'ship: 68(43) Last Wkt: Isuru Udana b Afridi 1(5) - 70/6 in 12.6 ov. Prev Ovs: 4 1 2 1 N1 1 4 . . 1 4 1 4 1 4 1 1 . 1 2 4 6 2 1 2