User guide

3-6
Cisco Media Gateway Manager 5.0 User Guide
OL-5461-02
Chapter 3 Planning the Network
What Network Elements Are Available to a Network Planner?
• Support for all ATM service classes, with up to 16 classes of service (CoS). Supports carrier-class
implementation of standards-based PNNI, SVC/SVP, SPVC/SPVP, and MPLS services.
• Large cell buffers (one million cells), which help to maximize performance during congestion,
reducing the number of retransmits; the buffers are allocated dynamically, depending on connection
resource needs, thereby optimizing use of system resources.
• High reliability with hot-standby 1:1 AXSM card redundancy, and 1:1 and 1+1 line redundancy
using APS.
3.2.8 Cisco MGX Service Resource Module
The Cisco MGX Service Resource Module (SRM) provides three major functions for service modules:
• Bulk distribution of T1 and E1 traffic
• Bit error rate testing of T1 and E1 lines and ports
• 1:N redundancy
The Cisco MGX-SRM operates at line speeds of OC-3 rather than DS3. The Cisco MGX SRM provides
the existing functionality of the SRM-3T3, such as bulk distribution, 1:N redundancy, and bit error rate
tester (BERT). It supports one SONET or Synchronous Digital Hierarchy (SDH) interface using
SMFIR-155 (optical) and SMB-155 (electrical) back cards.
The Cisco MGX SRM architecture is similar to that of the current SRM-3T3/C, with the following
additional features:
• Bulk distribution of T1 or E1 traffic to all 12 service module slots using one SONET or SDH
OC3/STM1 interface
• 1:1 SRM Hot-Standby Router Protocol (HSRP) redundancy
• Card-to-card linear (1+1) APS support for optical interfaces
• No back card requirement for SRM operation when bulk distribution is not required