Troubleshooting guide

1-18
Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 1 Solution Overview
Solution Components
The SRM/E card is another high-density bulk distribution card that removes some restrictions of the
SRM card. These cards support both ANSI and ITU-T interfaces of these optical and electrical options:
• opticalOptical: OC-1/OC-3, STM-0/STM-1 with APS
• electricalElectrical: STS-0/STS-1, STM-0, STM-1
The VISM modules create VoIP packets which are transported out the Cisco MGX88500 via the ATM
uplink on the PXM backcard.
PXM Modules
The Cisco MGX 8850 chassis supports the PXM45 processor card (along with PXM1 card). There are
two double-height slots (7/23 and 8/24) in positions seven and eight that are reserved for the redundant
Processor Switch Modules (PXMs). The PXM45 will provide up to 45 Gbps of switching capacity.
Additionally, four single-height slots in positions 15, 16, and 31, 32, are reserved for the other Service
Resource Modules (SRM or SRM/C). The SRMSRM/C module enables 1:N redundancy for the service
modules, BERT testing, and built-in M13 grooming. The remaining slots in positions 1-6, 9-14, 17-22,
and 25-30 are used for the service modules.
Trunking gateways can be configured with a "virtual" IP address associated with what is referred to as
the loop-back port–independent of the two IP addresses associated with the Ethernet interfaces. This
loop-back IP address is the one that the Call Agent should know about when talking to the Trunking
Gateway. It provides the optimum way of communicating with the Trunking Gateway in cases where one
of the Ethernet interfaces (or the Ethernet switch it is connected to) fails.
The Trunking Gateways can also be located in remote offices (remote from a Regional Center). For this
solution, we can use both remote and local Trunking Gateways. The gateway configuration (in terms of
line cards support) is the same for both remote and local Trunking Gateways. For instance in the case of
the MGX 8850, VISM and VISM-PR can be located in remote as well as in the regional center locations.
MF/CAS Trunks
For MF/CAS trunks, CAS signaling (ABCD signaling bits and MF tones) will be converted to/from
MGCP signaling requests and events by the Trunking Gateway. This includes:
• MF tones converted to/from digit strings inside either an MGCP Notify or Notification Request (or
combined with a Connection or Modify Connection Request).
• Off-hook and on-hook indications converted to/from events inside either an MGCP Notify or
Notification Request (or combined with a Connection or Modify Connection Request).
However, lower level signaling and timing will be done within the trunking gateway itself
(e.g. wink-start) rather than controlling via MGCP. MF wink-start incoming trunks for Busy Line Verify
and Operator Interrupt is compatible with the Feature Group D [TR-NPL-00258] termination protocol.
MF trunks for 911 and operator services are compatible with Feature Group D [TR-NPL-00258],
Operator Service (OS) Signaling protocol In this case the customer network appears to be a Regional
Bell Operating Company (RBOC) network.
ISUP Trunks
Given that there is no signaling on ISUP trunks, interaction with the Call Agent is limited to making
connections and doing continuity tests. MGCP 1.0 is used to send requests to the TGW to make or
modify connections in order to set up RTP media streams and to request connections for continuity tests.