NM’s – Network Modules

T3 Network Module – these have always been available on 7200 and 7500 series routers, but a new T3 Network Module, the NM-1T3/E3  -  is now available for smaller routers. It can be used with the 2650XM, 2651XM, 2691, 3660, 3725, and 3745.  The 3745 supports two NM-1T3/E3 modules.     Unlike other NM’s – it is for direct connection to two Coax BNC WAN connectors, and has no WIC slots.  It provides a T3 line for full-duplex communications at 44.736 MHz and full-duplex E3 communications at 34.368 MHz. Each T3 or E3 port consists of a pair of 75-ohm BNC coaxial connectors (Type RG-59), one for transmit data and one for receive data.

HSSI (High Speed Serial Interface), Cisco NM-1HSSI

High Speed Serial Interface (HSSI) Network Module NM-1HSSI

T3 or Fract DS3 (from 56 kbps to 52 Mbps)

*** will require an external IDSU (Kentrox or Adtran are fine) – to convert from HSSI to coax send/receive pair (the WAN DS3 interface will be a pair of coax cables)

The NM-1HSSI is a single port, high-speed network module that provides connectivity to a Wide Area Network. Demand for high capacity corporate backbones, high-speed Internet access, Virtual Private Networks (VPNs), and trunking connections for service provider internetworking has led to an increase demand for clear channel DS3 and E3 connections. Also see the NM-1T3/E3 clear channel T3/E3 Network Module (http://www.cisco.com/warp/public/cc/pd/ifaa/ps4909/prodlit/ttnp_ds.htm).

The NM-1HSSI Network Module supports speeds up to 52 Mbps. The NM-1HSSI also supports fractional T3/E3 speeds from 56 kbps to 52 Mbps.

Table 1   Cable Options for NM-1HSSI

Cisco T3/E3 Network Module

*** unlike HSSI, this does not require an external IDSU, because the COAX Send/Receive pair connects directly to DS3 WAN.

 provides high-speed WAN access for the Cisco 2600, 3600, and 3700 series routers. T3/E3 WAN access enables the network to carry high volumes of data and rich multimedia content, while providing low latency for voice over IP (VoIP).

Figure 1
Cisco T3/E3 Network Module

Cisco's Packet-over-T3/E3 network module for the Cisco 2600, 3600, and 3700 series offers the first software-configurable T3/E3 product from Cisco. This flexible network module allows the customer to switch between T3 and E3 applications with a single Cisco IOS® command. This feature provides customers with unparalleled investment protection by allowing the service provider or enterprise customer to stock only a single product that can be deployed internationally.

The demand for increased bandwidth has led to growth in clear-channel T3/E3 deployment. This new Packet-over T3/E3 network module (part number NM-1T3/E3) eliminates the need for an external data service unit (DSU), reduces provisioning costs, and provides highly manageable T3/E3 line termination. The module provides an integrated line interface unit (LIU) DSU that allows T3 or E3 lines to be directly terminated on a Cisco router, eliminating the need for external DSU equipment. This simplifies the T3/E3 line management, reduces provisioning cost, and frees valuable rack space.

Offering unprecedented flexibility in provisioning clear-channel T3 or E3 connections, the Cisco T3/E3 network modules provide support for the proprietary subrate and scrambling features of T3 DSU vendors Digital Link, Larscom, and ADC Kentrox. Subrate support in the Cisco T3/E3 Network Module maximizes the utility of these products in service provider environments for tiered DS3 services. By simultaneously supporting interoperability with a wide range of third-party DSU vendors, this network module offers the flexibility to support installed equipment without locking customers into a proprietary solution.

The Cisco T3/E3 Network Module provides direct connectivity to a T3 line for full-duplex communications at the T3 rate of 44.736 MHz and full-duplex E3 communications at 34.368 MHz. Each T3 or E3 port consists of a pair of 75-ohm BNC coaxial connectors (Type RG-59), one for transmit data and one for receive data, along with six LED indicators for line status. The Cisco 2650XM and 51XM, Cisco 2691, Cisco 3660, and the Cisco 3725 support a single T3/E3 network module. The Cisco 3745 supports up to two single-port Cisco T3/E3 network modules.

Because the Cisco T3/E3 Network Module is supported in Cisco IOS feature sets, including IP Only, there are no additional memory requirements for any supported platforms.

Key Benefits

The combination of T3 and E3 options in a single network module provides numerous important customer benefits:

·     Physical space savings—Eliminates the need for external DSU device, saving valuable rack space

·     Simplified management—Eliminates the need for two separate monitoring tools

·     Software-configurable T3/E3—Provides the flexibility to deploy a single module worldwide

Key Features

·     One-port T3 with DSU or E3 with DSU network module

·     T3/E3-specific features for monitoring, bit error rate tester (BERT), Management Information Bases (MIBs), alarms, and more

·     T3 configuration has the ability to independently or simultaneously enable scrambling and subrate in each DSU mode; support for the following DSU vendors' algorithms: Digital Link, Kentrox, Larscom, Verilink, Adtran

·     E3 configuration has the ability to independently or simultaneously enable scrambling and subrate in the Kentrox DSU mode. Digital Link is also supported for subrate E3; but without a scrambling option per industry standard.

·     Support for the serial encapsulation protocols: Frame Relay, Point-to-Point Protocol (PPP), High-Level Data Link Control (HDLC)

·     16-bit cyclic redundancy check (CRC)

Key Management Features

·     Line and payload loopback capabilities

·     DS3 remote-line loopback (via Far End Alarm and Control [FEAC] codes per American National Standards Institute [ANSI] T1.107a)

·     Response to embedded loopback commands

·     Insertion of loopback commands into transmitted signal

·     Programmable pseudorandom pattern up to 32 bits long, including 223, 220, 215, 1s, 0s, alt-0-1

·     32-bit error count and bit-count registers

·     Alarm detection—Alarm indication signal (AIS), remote alarm, far-end block error (FEBE), out of frame (OOF)

·     Onboard processor for Maintenance Data Link (MDL)

T3/E3 Applications and Positioning

The Cisco T3/E3 Network Module provides the high-speed performance required to build today's advanced, fully converged networks that need to support a wide array of applications and services such as security, and advanced quality of service (QoS) for voice and video. T3/E3 and subrate T3/E3 connectivity allows customers to take the fullest advantage of their WAN bandwidth for deploying the newest applications and service delivery. All the supported platforms are capable of supporting line-rate performance, but they use varying levels of CPU overhead and thus affect the overall platform performance. The Cisco 3745, for instance, is the highest-performing platform and is recommended for concurrent application environments where full wire rate is required. The Cisco 3725 and Cisco 3660 are the next highest-level performers; they have very similar CPU loading characteristics under comparable traffic conditions (refer to Table 1).

Table 1   Cisco T3/E3 Network Module Branch-Office Positioning

Four-Port Network Module (NM-4T)

The NM-4T serial network module has four synchronous serial interfaces. The network module supports a total full-duplex throughput of 8 megabits per second (Mbps), which can be realized over one port (at 8 Mbps) or across all four ports (at 2 Mbps on each port).

Network Interfaces

The Network Module has four serial interfaces using DB-60 connector. See Table 2 for the available cables.

Table 2   Cable Options for DB-60 Connectors

Serial NM’s (Network Modules)

Supported Features of Serial Network Modules

Supported Platforms

NM Table with links to Cisco Descriptions