Cisco Systems OC-12/STM-14 manual Using Loopback Commands, OC-12 Controller Loopback Mode

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Cisco IOS Software Configuration for the 1-Port Channelized OC-12/STM-4 (DS3) Line Card

How to Configure the 1-Port Channelized OC-12/STM-4 (DS3) Line Card

Using Loopback Commands

The 1-port channelized OC-12/STM-4 (DS3) line card supports loopback modes for both the OC-12 controller and for each of the associated DS3 channels. Specify the loopback mode by entering one of the loopback interface configuration commands shown in Table 5. Use the no form of this command to restore the default value, no loopback, which represents the normal operation between the local end (TX) and the remote end (RX).

Table 5

DS3 Supported Loopback Modes

 

 

 

 

Loopback modes

Configuration Mode

Command

 

 

 

Diagnostic or local loopback

loopback local

Router(config-if)# loopback local

 

 

 

Network loopback

loopback network

Router(config-if)# loopback

 

 

 

network

 

 

 

Remote loopback

loopback remote

Router(config-if)# loopback remote

 

 

 

Default value

default value

Router(config-if)# no loopback

 

 

 

 

Figure 1 shows data flows for the various loopback modes.

Figure 1 Transmit and Receive Loopback Data Flows

Internal loopback

OC-12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fiber

 

 

 

 

 

 

Mux/

 

 

 

 

 

 

STTX

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

demux

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Line

loopback

OC-12

Internal loopback

 

STS-3

 

SUNI

Layer 3

routing

622

engine

 

 

11979

OC-12 Controller Loopback Mode

The OC-12 controller supports two loopback modes:

Internal—This loopback mode loops data from the transmit path to the receive path at the mux/demux location on the line card, allowing diagnostics to send data to itself at the OC-12 level without relying on external connections. In controller configuration mode, set the loopback mode to internal, using the [no] loopback [internal line ] configuration command:

Router(config-controller)# loopback internal

Router(config-controller)#

Use the no form of this command to restore the default value, no loopback.

Cisco IOS Release 12.0(8)S

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Contents Contents Configuring the OC-12 Controller Router# show controller oc12 1/0Router# configure terminal Routerconfig# controller OC12 1/0Configuring the DS3 Serial Interface Configuration Command Default ValueRouterconfig# interface serial 1/01 Routerconfig-if#ip address 10.1.2.3Router# copy running-config startup-config Cisco Remote Connection ManagementNo dsu mode No framing c-bit m13Cisco digital-link kentrox larscom No dsu bandwidth Kilobits/secVerifying Local and Remote DS3 Port Settings Selecting a DSU ModeSetting the Sending and Receiving Rate Configuring the DSU Bandwidth RangeUsing show Commands to Check System Status Configuring Cyclic Redundancy ChecksConfiguring the Clock Source Enabling Payload ScramblingShow controllers oc12 slot/port Router# show controllers oc12 1/0Show controllers oc12 slot/portchannel# Show controllers oc12 detailRouter# show controllers oc12 1/01 Router# show running-config Ip subnet-zeroUsing Loopback Commands OC-12 Controller Loopback ModeLoopback modes Configuration Mode Command Configuring DS3 Port BER Testing DS3 Channel Loopback ModeNo loopback local network remote configuration command Checking Bit Errors Using a Bert Bert Pattern To Invoke CommandEntering Errors in BER Tests Using show Commands to Verify Bert ConfigurationRouter# show controller oc12 1/01 bert Bert Information Explanation BertBert Information Explanation Routerconfig-if#ip address 1.1.5.1 Related Documents Technical AssistanceRelated Topic Document Title Description Link

OC-12/STM-14 specifications

Cisco Systems OC-12/STM-14 is a high-performance networking solution designed to meet the demands of modern telecommunications and data transport applications. Operating at a data rate of 622 Mbps, the OC-12 (Optical Carrier level 12) and STM-14 (Synchronous Transport Module level 14), this technology provides a reliable and efficient method for organizations to transmit large volumes of data over fiber optic networks.

One of the key features of the OC-12/STM-14 system is its capability for high-speed data transfer. This makes it an ideal choice for service providers looking to deliver broadband services, video streaming, and other bandwidth-intensive applications. With support for multiple protocols, including SONET (Synchronous Optical Network) and SDH (Synchronous Digital Hierarchy), the OC-12/STM-14 can facilitate smooth communication and interoperability between various network devices.

Another significant characteristic of the OC-12/STM-14 is its scalability. Organizations can easily scale their networks by adding additional OC-12/STM-14 connections, accommodating their growing bandwidth needs without a complete overhaul of existing infrastructure. This flexibility is essential for businesses that expect fluctuations in data traffic or are anticipating future expansion.

Additionally, Cisco's OC-12/STM-14 employs advanced error correction and fault tolerance features, ensuring high reliability and minimal downtime. It supports sophisticated monitoring and network management capabilities, allowing administrators to proactively manage network performance and troubleshoot potential issues before they affect service quality.

Security is also a critical aspect of the OC-12/STM-14 architecture. Cisco incorporates robust security protocols to safeguard sensitive data during transmission, ensuring compliance with industry standards and protecting against unauthorized access.

In terms of compatibility, the Cisco OC-12/STM-14 integrates seamlessly with existing infrastructure and can work alongside various routing platforms. This compatibility significantly reduces the cost and complexity associated with upgrading legacy systems.

Ultimately, Cisco Systems OC-12/STM-14 offers a powerful solution for enterprises and service providers looking to enhance their networking capabilities. With its high-speed data transfer, scalability, reliability, and security features, it stands as a cornerstone technology in advanced telecommunications and data networking.