Bridging Or Time Space Switch - Avaya Media Processing Server 1000 Hardware Installation And Maintenance

System clock distribution is unique in that it is distributed between the NIC master and slave. The
NIC master does not necessarily distribute the system clock to and from the backplane. Reference
clock A is distributed by the NICs l in backplane slot 7 while reference clock B is distributed by the
NICs in backplane slot 8. This arrangement minimizes the possibility of a single NIC failure
disrupting the system clock within a chassis.
Selection of the primary or secondary reference to the PLL in a chassis is determined by which
source is detected first. The first clock detected is the primary source. Every chassis need not select
a common clock source as the primary reference. The clocks must be in phase, but ATM
compensates for any minor phase mismatch in inter-chassis bridging. However, intra-chassis
bridging requires that all boards on the common backplane select a common reference. The NIC
controls the selection of a primary and secondary reference within its chassis.
A system is functional if each chassis has at least one clock source available for a primary
reference, although it is preferable for both system clocks to be available.
The loss of any NIC can disrupt the distribution of system clocking. If a chassis is a clock source,
clock distribution to all other chassis can be affected. For a clock sink, a NIC failure can disrupt one
of the clocks in that backplane only.
Troubleshooting
1. Verify that all the NICs in a system are booted using the system status command of NCD.
2. Check all inter-chassis cabling for clocking, check for missing or incorrect impedance on
cables, and that the cables are routed correctly.
3. Verify that TMS selected as clock sources in the tms.cfg file are running and the spans in the
sync list are in service.

Bridging or Time Space Switch

Intra-chassis bridging on the TMS is supported on MVIP highways within the chassis. The MVIP
highways are a set of TDM streams that connect each TMS to the NIC. Each TMS backplane slot
has 256 full-duplex channels or connections to the NIC. These 256 nonblocking channels are
divided to 8 half-duplex streams that support 64 TDM channels per stream.
The TMS and NIC use a Time Space Switch (TSS) to connect the audio path. Each TMS has 256
nonblocking channels or MVIP highways while the NIC has 1024. The backplane has eight unique
lands dedicated to each TMS slot which are connected to each NIC slot, 64 unique lands at the NIC.
When bridging two calls within the chassis, the NIC allocates a pair of MVIP highways for each TMS
and makes the appropriate connections on the TSS. The TMS attaches its local TDM highways,
through its local TSS, to this set of external highways completing the audio path between the two
lines. The application controls when the audio path is complete.
In a redundant pair, the NICs always synchronize the TSS connections. The slave is a hot standby
but does not attach the TSS I/O to the backplane. Failure of the NIC master causes the NIC slave to
enable the TSS on the backplane and therefore, recover any audio.
October 2014 Avaya Media Processing Server 1000 Hardware Installation and Maintenance
Comments? infodev@avaya.com
Bridging or Time Space Switch
187