Operating Manual
KE3500
xDSL
M
ULTI
T
EST
TEI
The Terminal Endpoint Identifier (TEI) is an identifier in the ISDN signaling protocol DSS1 used to identify the
terminals. Together with the Service Access Point Identifier (SAPI), the TEI forms a unique address for one
specific terminal in the data link layer (layer 2) of the D channel.
Timeout
Designates the time period that must expire before a process is canceled with an error. Time limitations make
most sense to avoid situations where a process is waiting for something that either never occurs or only occurs
after a very long delay. With regard to process synchronization, a timeout is that period of time for which a
process should wait for the occurrence of a condition before an error is tripped. Especially with regard to
computer networks, timeouts identify the time for which a process waits for a response before a data packet is
considered lost and must either be transmitted again (retry) or communication is canceled with a (timeout)
error.
Traceroute
Traceroute transmits multiple IP data packets to the destination host starting with a Time-to-live (TTL) of 1. The
first router to relay the data packet decrements the value of the TTL by one to 0. It does not relay the packet but
rather discards it because of this value. In this case, it transmits the ICMP response type 11: Time exceeded
with a code of 0: Time to live exceeded in transit back to the source. This data packet contains the IP address of
the router involved as its source address. This information is recorded by the Traceroute program together with
the total round-trip time. After this, the program repeats this step with a TTL incremented by 1 to determine the
next router in the path through the network. This process is repeated until either the destination host or the
maximum number of hops used by the Traceroute program has been reached. The sequence of addresses
collected in this way identifies the path through the network to the destination. The return path is usually
identical but may differ in the case of asymmetrical routing. As a rule, three packets are sent to each host. The
Traceroute result does not always show the actual path. It is affected by firewalls, incorrect implementations of
the IP stack, network address translation, IP tunnels or by the selection of a different path in the case of a
network overload, and other factors.
URL
A Uniform Resource Locator (URL) identifies and localizes a resource such as a website by way of the access
method to be used (for example, the network protocol used such as HTTP or FTP) and the location of the
resource in computer networks. The current version is published as RFC 1738. The RFC specifications are the
industrial standards of the Internet Foundation IETF. URLs are a subtype of the general identification
designation using Uniform Resource Identifiers (URIs). As URLs represent the first and most frequent type of
URIs, the concepts are frequently used synonymously. In common usage, URLs are also known as Internet
addresses or web addresses, which usually (with the Internet and WWW being frequently identical
idiomatically) means the special URLs of websites.
UAS
Number of seconds during which no transfer was possible.
Vectoring
Very-high-bit-rate digital subscriber line 2 (VDSL2) is an access technology that exploits the existing
infrastructure of copper wires that were originally deployed for traditional telephone service as a way of
delivering very high speed internet access. The main high-speed link (e.g. a fibre optic connection) terminates
at a hub near the customers' location. The existing copper wire infrastructure is then used to carry the high
speed connection for the short remaining distance to the customers. It can be deployed from central offices,
from fiber-optic connected cabinets located near the customer premises, or within buildings. It has been
defined in standard ITU-T G.993.2 finalized in 2005. VDSL2 is an enhancement to very-high-bit-rate digital
subscriber line (VDSL), Recommendation G.993.1, and is the newest and most advanced currently deployed
standard of digital subscriber line (DSL) broadband wireline communications. Designed to support the wide
deployment of triple play services such as voice, video, data, high-definition television (HDTV) and interactive
gaming, VDSL2 is intended to enable operators and carriers to gradually, flexibly, and cost-efficiently upgrade
existing xDSL infrastructure. The protocol is standardized in the International Telecommunication Union
telecommunications sector (ITU-T) as Recommendation G.993.2. It has been announced as finalized
on 27
May 2005, and first published on 17 February 2006. Several corrections and amendments have been
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