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Overview Installation Troubleshooting | Contact | FAQ | Specifications | Glossary | License |
Configuration: Basic | Gateway | TCP/IP | Wireless USB | ||
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datagram | In RFC 1594, a datagram is defined as “a |
| information to be routed from the source to the destination computer without reliance on earlier |
| exchanges between this source and destination computer and the transporting network.” For the most |
| part, it has been replaced by the term packet. |
default route | The route by which packets are forwarded when other routes in the routing table do not apply. |
dB | decibel |
dBc | Signal level expressed in dB relative to the unmodulated carrier level desired. |
DBm | A unit of measurement referenced to one milliwatt across specified impedance. 0dBm = 1 milliwatt |
| across 75 ohms. |
dBmV | Signal level expressed in dB as the ratio of the signal power in a |
| when 1 mV is across 75 ohms. |
demodulation | An operation to restore a previously modulated wave and separate the multiple signals that were |
| combined and modulated on a subcarrier. |
DHCP | A Dynamic Host Configuration Protocol server dynamically assigns IP addresses to client hosts on an |
| IP network. DHCP eliminates the need to manually assign static IP addresses by “leasing” an |
| IP address and subnet mask to each client. It enables the automatic reuse of unused IP addresses: |
| The SBG940 is simultaneously a DHCP client and a DHCP server. |
| • A DHCP server at the cable system headend assigns a public IP address to the SBG940 and |
| optionally to clients on the SBG940 LAN. |
| • The SBG940 contains a |
distortion | An undesired change in signal waveform within a transmission medium. A nonlinear reproduction of |
| the input waveform. |
DMZ | A |
| A DMZ prevents direct access by outside users to private data. (The term comes from the geographic |
| buffers located between some conflicting countries such as North and South Korea.) In a typical small |
| DMZ configuration, the DMZ host receives requests from private LAN users to access external web |
| sites and initiates sessions for these requests. The DMZ host cannot initiate a session back to the |
| private LAN. Internet users outside the private LAN can access only the DMZ host. You can use a |
| DMZ to set up a web server or for gaming without exposing confidential data. |
DNS | The Domain Name System is the Internet system for converting domain names to IP addresses. A |
| DNS server contains a table matching domain names such as Internetname.com to IP addresses |
| such as 192.169.9.1. When you access the |
| displayed on the browser to the destination website IP address. The DNS lookup table is a distributed |
| Internet database; no one DNS server lists all domain name to IP address matches. |
DOCSIS | The CableLabs |
| modems, gateways, and supporting equipment to deliver data between an HFC network and a |
| computer systems or television sets. To emphasize its use as a cable modem standard, DOCSIS is |
| now called CableLabs Certified Cable Modems. |
domain name | A unique name, such as motorola.com, that maps to an IP address. Domain names are typically much |
| easier to remember than are IP addresses. |
DSSS | Direct Sequence Spread Spectrum |
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