Blocking; Cardlan - Avaya Communication Server 1000M Single Group Manual

Description

Blocking

With the number of TNs greater than the number of T1 channels, calls between the remoted
line card and the switch may be blocked due to the lack of an available timeslot. Normally, all
signaling messages between the RMI and the switch are passed through the MCR system,
but not during blocked situations.
Analog cards and digital cards handle blocking differently. For analog sets, ringing messages
destined for a remoted line card are dropped when a time-slot allocation is attempted but a
timeslot is not available. This enables the caller to be forwarded to voice mail when no timeslots
are available. Also, when no timeslots are available, off-hook messages from the remoted
phones are not transported across the MCR. Instead, the remote user receives re-order, or
fast-busy (a fast busy signal) to indicate that no timeslot is available.
With digital sets, ringing messages are not dropped when no timeslots are available. If the user
answers a ringing telephone when no timeslots are available, the user receives a re-order
signal to indicate the blocked situation. The caller will hear silence, since the MCR system is
out of timeslots.

CardLAN

The local LMI and LMX act as a cardLAN slave to the XPEC or CPU card.
The RMI board sits in the CPU slot and therefore is the cardLAN master. The local boards wait
for the RMI to enable them to respond to their cardLAN master. The RMI polls all 10 line card
slots at the remote site in a round-robin fashion and looks for newly inserted cards.
Upon LMX detection, the RMI queries the LMX with all known cardLAN messages so that it
can provide this information to the local card that is emulating that LMX. Upon receiving the
last message from the RMI, the local board begins responding to polls normally. At each local
cardLAN query, the local card responds immediately, and it also sends that query to the RMI.
The RMI then queries the remoting LMX and sends the response back to the local card. This
method keeps the local site one poll behind, but this is necessary to be able to respond to
cardLAN fast enough at the local site over long T1 distances.
If the RMI detects that an LMX has been removed or changed, it disables or initializes the
appropriate local card's cardLAN task. Also, if the local card receives a cardLAN message that
is undefined, no attempt is made to answer that message. Should the existing line cards be
updated such that they operate on an expanded cardLAN message set, the MCR system must
also be updated.
32 Mini-Carrier Remote Fundamentals
Comments? infodev@avaya.com
March 2013