Zultys MX250, Hardware Manual

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MX250 Hardware Manual
Repeater. A device that receives a digital signal on a transmission medium and regenerates the
signal for the next leg of the medium. Repeaters overcome attenuation losses caused by free-space
electromagnetic-field divergence or cable loss over electromagnetic media. A series of repeaters
facilitates the extension of a signal over long distances.
Request for Comments (RFC). A formal document issued by the Internet Engineering Task Force.
Some RFCs are informational in natural while others become Internet standards. RFCs are the
result of committee drafting and subsequent review by interested parties. No further comments
or changes to an RFC are permitted once it becomes an Internet standard; changes to internet
standards are enacted through subsequent RFCs that supersede or elaborate on all or parts of
existing RFCs.
Reverse Address Resolution Protocol (RARP). A protocol by which a physical machine in a local
area network can request its IP address from a gateway server’s Address Resolution Protocol table
or cache. RARP is described in RFC 903.
RJ-45. A single-line digital transmission interface. Resembling a standard phone connector, an
RJ-45 connector is twice as wide (with eight wires) and is used for connecting computers to local
area networks (LANs) or phones with multiple lines.
Router. A device that determines the next network point to which a data packet should be sent on
the to its final destination. Routers also act as traffic cops, allowing only authorized machines to
transmit data into the local network so that private information can remain secure. In addition to
supporting these dial-in and leased connections, routers also handle errors, maintain network
usage statistics, and handle security issues.
Security Parameters Index (SPI). A hexadecimal value which uniquely identifies each tunnel.
Server. A computer program or device that provides services to other computers.
Server Farm. A network where clients install their own computers to run Web servers, email, or
any other TCP/IP based services they require, making use of leased permanent Internet
connections with 24-hour worldwide access. Instead of using expensive dedicated-line
connections to various offices, servers can be placed on server farm networks to provide
high-speed Internet access for a fraction of the cost of a leased line.
Session Description Protocol (SDP). An ASCII-based protocol that describes multimedia sessions
and their related scheduling information, including information transport session participant
port numbers and contact addresses. The ZIP 4x4 phone uses SDP for session descriptions as
documented in RFC 2327.
Session Initiated Protocol (SIP). An Internet standard protocol that defines a method of initiating
an interactive user session involving multimedia elements, such as voice, chat, gaming, video,
and virtual reality. SIP is a request-response protocol that deals with requests from clients and
responses from servers through any transport protocol, such as UDP or TCP. Described by RFC
3261, SIP can establish, modify, or terminate multimedia sessions or Internet telephony calls.
Simple Network Time Protocol (SNTP). A protocol that synchronizes computer clocks on an IP
network. Similar to NTP with fewer features. Some IP phones use SNTP for their date and time
synchronization functions. Described by RFC 2030.
SIP Endpoint. An internet host that understands the SIP protocol.
SIP Registrar. A SIP Registrar is a UAS that responds to REGISTER requests and maintains a list
of bindings that are accessible to proxy servers and redirect servers within its administrative
domain.