Network Signaling On Virtual Network Services - Nortel Meridian Meridian 1 Feature Description And Administration

Page 1392 of 1814
Feature description
553-2901-301 Standard 9.00 January 2002

Network Signaling on Virtual Network Services

The Network Signaling on Virtual Network Services (NSIG on VNS) feature
enhances the functionality of Virtual Network Services by supporting
Network Signaling on the VNS D-Channel (VNS_DCH).
With VNS, the Public Switched Telephone Network (PSTN) trunk serves as
a B-Channel. However, NSIG is not allowed over PSTN trunks; therefore, it
is necessary to send NSIG over the D-Channel in order to maintain the
Network Class of Service (NCOS) information.
NCOS information is transported via Network Signaling over routes,
depending on the value of the Signaling arrangement (SIGO) prompt in the
Route Data Block. When SIGO = STD, no NCOS information is sent on the
Bearer Channel (B-Channel).
The value of the Virtual Signaling (VSIG) prompt in Overlay 17 determines
whether or not NSIG is supported on the VNS D-Channel. When
VSIG = NO, NSIG is not sent over the VNS D-Channel. When VSIG = YES,
NSIG is sent over the VNS D-Channel, and the standard ESN5 protocol is
used.
VSIG = YES and SIGO is set to STD
In this situation, NSIG is configured on the VNS D-Channel. Two nodes are
connected by a VNS D-Channel, and the bearers are TIE trunks connected to
the Central Office (CO). When Set A initiates a call to Set B, using the VNS
D-Channel, the NCOS of Set A travels over the VNS D-Channel using ESN5
protocol and is present at the terminating node for further access restrictions.
No Network Signaling is on the bearer in this case.
VSIG = YES and SIGO is not set to STD
In this situation, NSIG is configured on the VNS D-Channel and on the
bearer. When Set A initiates a call to Set B, the NCOS of Set A travels over
the VNS D-Channel and on the bearer.
VSIG = NO and SIGO is not set to STD
In this situation, NSIG is not configured on the VNS D-Channel. When Set A
initiates a call to Set B, no NCOS information travels over the VNS
D-Channel, but will travel on the bearer.