9
PERMANENT LOGICAL LINK (PLL)APPLICATIONS
Ed. 04 1/4Réf. 3EH 21000 BSAA
File
PERMANENT LOGICAL LINK (PLL)
The Permanent Logical Link (PLL) service handles the simultaneous bi-directional transfer of data fra-
mes between a T interface (T0 or T2) and an S0 interface (ePLL) or between 2 S0 interfaces (iPLL), each
interface being one extremity of a semi-PLL with:
- either a public network Packet Access Point (PAP) on the T interface side
- or an S0 terminal connected to the S0 bus on the S0 interface side.
The data packets are exchanged on this link in a transparent way through the D channels of these ac-
cesses.
The rate for this type of data transmission is limited to 9600 bps.
The link between the 2 Alcatel OmniPCX Office interfaces that connect the 2 semi-PLLs is established
by configuring a routing table.
The S0 terminals are connected to 4084 or 4094 interfaces.
DEFINITIONS
- SAPI: Service Access Point Identification; the value in the SAPI field identifies the type of information
transported by the data link and, for this reason, identifies the targeted access point, source or fra-
me destination. By default, a SAPI value of 16 is assigned to links carrying X25 type packets to the
PAP.
- TEI: Terminal Extremity Identification
EXTERNAL PLLs
The system makes it possible to establish one or several external PLLs (ePLLs) between T accesses of
the system and a data network access port and also to extend them to S0 accesses according to the
following rules:
- each ePLL associates the trinome [Interface T, SAPI (16), TEI] with an [Interface S0, SAPI (16), TEI]
trinome.
- a T or S0 interface can be used for several ePLLs (max. 4) by changing the TEI value.
To Next Page
Loading...
Need help?
General