Operating Manual
KE3600
xDSL
M
ULTI
T
EST
TE
Terminal Equipment, a designation for data terminal equipment that is often used.
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.
VLAN
A Virtual Local Area Network (VLAN) is a logical subnet within a switch or an entire physical network. It may
extend over one or more switches. A VLAN separates physical networks into subnets by ensuring that VLAN-
compatible switches do not relay the frames (data packets) of one VLAN into another VLAN and this even
though the subnets can be connected to common switches. Tagged VLANs involve networks that use network
packets bearing additional VLAN identification marks. Tagging in VLANs is also used if the VLANs extend, for
example, over several switches, say, via trunk ports. In this case, the frames bear an identification mark that
indicates association with the appropriate VLAN.
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