Cisco 12000 Series Routers

Cisco 12000 2-Port Channelized OC-3/STM-1 (DS1/E1) Line Card

Data Sheet

Cisco 12000 Series

Two-Port Channelized OC-3c/STM-1c (DS1/E1) Line Card

The Cisco 12000 Series Two-Port Channelized OC-3c/STM-1c (DS1/E1) Line Card provides Cisco 12000 Series Internet Routers support for DS-1/E-1 aggregation. Designed for telcos and Internet service providers (ISPs), this card supports two OC-3c/STM-1c ports, each of which can be configured with multiple channels of (n)xDS-1, DS-1, fractional DS-1, or DS-0 in a Synchronous Optical Network (SONET) environment or (n)xE-1, E-1, fractional E-1, or 64 kbps in a Synchronous Digital Hierarchy (SDH) environment. Cisco 12000 Series channelized line cards integrate the channel service unit/data service unit (CSU/DSU) function on a per-port basis. In conjunction with other Cisco 12000 Series line cards, a single router in the carrier point of presence (POP) can scale fractional DS-1 to OC-192c in a SONET environment and from fractional E-1 to STM-64c (VC-4-64c) in an SDH environment.

Figure 1
Cisco 12000 Series Two-Port Channelized OC-3c/STM-1c (DS1/E1) Line Card

Product Description

The Cisco 12000 Series Two-Port Channelized OC-3c/STM-1c (DS1/E1) Line Card (2-Port CHOC-3) provides advanced DS-1/E-1 aggregation, with two optical connections (Figure 1). Each interface, when configured in SDH framing mode, is capable of supporting channelization into 63 independent E-1 (VC-12 mapping) channels in an SDH configuration. When configured for SONET framing mode, each interface is capable of supporting channelization into 84 independent DS-1 (VT1.5 mapping or CT-3 mapping into STS-1) channels in a SONET configuration. Fractional E-1 and individual 64 kbps channels can also be configured, up to the limit of 105 channel-group definitions per STM-1 (35 per TUG-3). Fractional T-1 and individual DS-0 channels can also be configured, up to the limit of 35 channel-group definitions per STS-1 (210 per line card). Each Cisco 2-Port CHOC-3 Line Card supports up to 126 E-1 connections in an SDH configuration and 168 DS-1 connections in a SONET configuration, or any combination of
DS-0/64 kbps, fractional T-1/E-1, and
T-1/E-1 interface definitions up to 210 channel groups per line card.

The Cisco 2-Port CHOC-3 Line Card supports full class of service (CoS) on each and every interface, including Multilink Point-to-Point Protocol (MLPPP) bundles. Eight CoS queues, along with weighted random early detection (WRED) and modified deficit round robin (MDRR), provide the same CoS for individual serial interfaces as all other Cisco 12000 Series line cards, up to and including the Cisco One-Port OC-192c/STM-64c Packet Over SONET (POS) Line Card. This provides the infrastructure required to enable service providers to provision CoS throughout their entire network, rather than sacrificing this essential capability at the very point (relatively smaller links) where it is needed the most.

The Cisco 2-Port CHOC-3 Line Card can be used in any Cisco 12000 Series Internet Router. All Cisco 12000 Series line cards support "hitless" online insertion and removal (OIR).

The Cisco 2-Port CHOC-3 Line Card supports the full richness of the Cisco IOS® Software service provider feature set. This enables service providers to deploy a wide range of services across their entire network, whether DS-1/E-1 or OC-192c/STM-64c; no compromise or tradeoff is required for lower-speed links.


SDH Aggregation

SDH as a transport technology is an established technology in E-1 carrier regions. Most operators, incumbents and new ones, have significant investment in large SDH networks deployed mainly in metro and regional access networks, typically to support voice traffic. The reasons for using SDH for access are:

  • The need to support voice and data services over the same transport aggregate
  • SDH is a known technology having good performance, error monitoring, and resilience
  • SDH supports centralized service provisioning at various bandwidths, from E-1 to E-3/DS-3, full STM-1c, and beyond
  • SDH provides better utilization of existing transmission infrastructure

Service providers can exploit deployed SDH to provision both voice and data circuits all the way to a customer's premises. The Cisco 2-Port CHOC-3 Line Card takes advantage of existing infrastructure, significantly lowering provisioning costs in terms of transmission and routing equipment.

Traditionally, data leased-line aggregation has been deployed using Frame Relay and Asynchronous Transfer Mode (ATM) networks deployed over SDH networks. In cases where leased lines were provided by a global or continental service provider, the E-1 or fractional E-1 leased lines were transported over the transmission provider SDH network and handed over using E-1 connectivity to the service provider POP (Figure 2).

Figure 2
STM-1c to Channelized E-1 Aggregation

As businesses require greater bandwidth connectivity to support increased IP traffic loads, E-1 and greater bandwidth are becoming increasingly common for access connections. The growth in the number of provisioned E-1 service connections is driving the need for more E-1 port capacity on service provider aggregation routers, requiring more routers, space, and power in their POPs. The Cisco 2-Port CHOC-3 Line Card allows service providers to connect multiple E-1 leased-line customers into one Cisco 12000 Series Internet Router line card slot, greatly reducing the amount of aggregation equipment and interconnectivity needed between edge and backbone routers, as well as enabling support of single router (edge and backbone) POP architectures (Figure 2).

By supporting both PPP and Frame Relay, the line card allows easy transition of connectivity from Frame Relay networks to direct IP leased-line grooming over SDH networks, thus allowing a simple transition to high-bandwidth, full-feature aggregation solutions on Cisco 12000 Series Internet Routers.

Key Features and Benefits

Designed for concentrating IP access over telco time-division multiplexing (TDM) networks, the Cisco 2-Port CHOC-3 Line Card:

  • Concentrates up to 168 DS-1s in one line card. This increases density per rack and overall router capacity, enabling service providers to scale networks cost-effectively.
  • Supports any combination of DS-0/64 kbps, fractional T-1/E-1, and T-1/E-1 interface definitions up to 210 channel groups per line card. Service providers can accommodate customers using telco TDM networks for access with a wide range of bandwidth requirements, from DS-0 to multiple T-1s and E-1s.
  • Provides guaranteed priority packet delivery for both IP and Multiprotocol Label Switching (MPLS) traffic. This includes MDRR queuing algorithm, which provides low-latency queuing for high-priority applications such as voice over IP, and unique priority-based WRED, which provides congestion control. Packet sequence integrity is not compromised under any condition.
  • Supports service-transparent online insertion and removal, allowing line cards to be removed without impacting traffic.

Cisco continues to build on its technical leadership in high-end Internet routing with the introduction of the Cisco 12000 Series Two-Port Channelized OC-3c/STM-1c (DS1/E1) Line Card. The Cisco 12000 Series is the premier Internet routing platform for building the highest capacity and highest value IP networks. When coupled with the Cisco 2-Port CHOC-3 Line Card, it provides high density T-1 and E-1 aggregation enabling service providers to build powerful, cost-efficient networks to serve large numbers of customers using telco infrastructure for IP access.

Table 1   Product Specifications

Product Specifications
Chassis compatibility
  • Cisco 12008, 12012, 12016, 12404, 12406, 12410, and 12416
Software compatibility
  • Cisco IOS Software Release 12.0(17)S or higher
  • Cisco IOS Software Release 12.0(17)ST or higher
  • IETF RFC 1490, Frame Relay encapsulation
  • RFC 1662, PPP in HDLC-like framing
  • Multilink support (42 bundles up to 8 T-1/E-1 per bundle):
    • Multilink PPP (MLPPP)
    • Multilink Frame Relay (MLFR)
  • Cisco High-Level Data Link Control (HDLC)
  • Cisco Discovery Protocol
  • Internet Control Message Protocol (ICMP)
  • Layer 3 routing protocols include Border Gateway Protocol Version 4 (BGPv4), Open Shortest Path First (OSPF), Intermediate System-to-Intermediate System (IS-IS), Enhanced Interior Gateway Routing Protocol (EIGRP), IGRP, Routing Information Protocol (RIP), RIPv2, and others
  • Multicast forwarding with support for source and shared distribution trees and the following protocols: Protocol Independent Multicast-Dense Mode (PIM-DM), PIM-Sparse Mode (PIM-SM), Auto Rendezvous Point (AutoRP), IGMPv1/v2, Cisco Group Management Protocol, Multiprotocol BGP (MBGP), Multicast Source Discovery Protocol (MSDP), and others
  • Comprehensive MPLS support
  • Traffic engineering using Routing with Resource Reservation (RRR)
Port density
  • Two OC-3c/STM-1c SONET/SDH interfaces per line card per chassis slot
  • Up to 15 cards, 30 OC-3c/STM-1c ports (1890 E-1/2520 DS-1) per Cisco 12016 or 12416 chassis
  • Up to 11 cards, 22 OC-3c/STM-1c ports (1386 E-1/1848 DS-1) per Cisco 12012 chassis
  • Up to 9 cards, 18 OC-3c/STM-1c ports (1134 E-1/1512 DS-1) per Cisco 12410 chassis
  • Up to 7 cards, 14 OC-3c/STM-1c ports (882 E-1/1176 DS-1) per Cisco 12008 chassis
  • Up to 5 cards, 10 OC-3c/STM-1c ports (630 E-1/840 DS-1) per Cisco 12406 chassis
Per-port features
  • 1310 nm single-mode (SM), intermediate-reach (IR), S-1.1 compliant optical interface
  • Channelization down to the nxDS-0 level (a total of 126 E-1s or 168 T-1s); a maximum of 35 channels per path is supported (per DS-3, STS-1, TUG3, or AU3)
  • Internal or line-derived (loop) clocking independently selectable on each optical port
  • SONET/SDH alarm processing and performance monitoring (see Table 2)
  • HDLC support for shared flags, configurable IDLE pattern, and 16- or 32-bit cyclic redundancy check (CRC)
  • Bit error rate testing (BERT)
  • Support for SONET Virtual Tributary 1.5 (VT1.5) mapping: OC-3 <-> STS-3 <-> STS-1 <-> VTG <-> VT1.5 <-> DS-1
  • Support for asynchronous DS3 channelized down to DS-1 (M13 and C-bit framing) mapped into: OC-3 <-> STS-3 <-> STS-1 <-> DS-3 <-> DS-2 <-> DS-1
  • Support for ITU-T G.707 (SDH CEPT/ETSI) Virtual Container 12 (VC-12) mapping: STM-1 <-> AUG <-> AU-4 <-> VC-4 <-> TUG-3 <-> TUG-2 <-> TU-12 <-> VC-12 <-> E-1
  • Support for ITU-T G.707 (SDH-ANSI) Virtual Container 11 (VC-11) mapping: STM-1 <-> AUG <-> AU-3 <-> VC-3 <-> TUG-2 <-> TU-11 <-> VC-11 <-> J1
  • Loopback capabilities: local and network at the OC-3/STM-1 level
DS-1 specific features
  • Superframe (SF) and Extended Superframe (ESF) support
  • ANSI T1.403 FDL support
  • Internal or line-derived (loop) clocking, independently selectable on each T-1 tributary
  • Error and alarm detection: CRC errors, framing errors, loss of frame (red), AIS (blue), remote alarm indication (yellow)
  • Alarm reporting—24-hour history maintained, 15-minute intervals on all errors
  • BERT at T-1 level
  • Loopback capabilities: local, network line and network payload, remote network line and remote network payload at the T-1 level
E-1 specific features
  • ITU-T G.703, as applicable
  • Framing: CRC-4 and no-CRC-4 conformance with ITU-T G.703 and G.704
  • Internal or line-derived (loop) clocking, independently selectable on each E-1 tributary
  • Error and alarm detection: CRC errors, framing errors, loss of frame, AIS, remote alarm indication
  • Performance monitoring: 24-hour history retained; 15-minute intervals on all errors
  • BERT at E-1 level
  • Line and payload loopback capabilities—local and network line, and network payload at the E-1 level
Features not supported
  • Unframed DS-3 (HSSI)
  • DS-2 loopbacks, alarms, performance monitoring, or Management Information Base (MIB) support
  • DS-1 signaling
  • E-1 time slot 16 (TS16) signaling multiframe
  • E-1 Bit Oriented Protocol (BOP)
  • E-1 remote loopback
  • 128 MB of route table memory (default, no options)
  • 256 MB optional
  • Line rate for IMIX traffic profile
Reliability and availability
  • OIR enabling insertion and removal of line cards without impacting traffic
  • Will support both SONET Automatic Protection Switching (APS) and SDH Linear Multiplexer Section Protection (MSP) protocols
Network management
  • Cisco IOS Software command-line interface (CLI)
  • Cisco 12000 Manager for configuration, fault, and performance element management
  • Simple Network Management Protocol (SNMP)
  • Specific supported MIBs
    • RFC 2558 (SONET/SDH MIB)
    • RFC 2496 (DS-3 MIB)
    • RFC 2495 (DS-1/E-1 MIB)
SONET/SDH functions supported
  • Compliance with G.707, G.783, G.784, G.957, G.958, GR-253, as applicable
  • See Table 2 for supported alarm and signal events
  • Synchronization Local (internal) or loop timed (recovered from network)
  • Local (diagnostic) and line (network) loopback
Visual status indicators (LEDs)
  • Active
  • Carrier
  • Alpha-numeric management display
  • 85 watts
Physical specifications
  • Occupies one line card slot
  • Weight: 10.21 lb (4.64 kg)
  • Height: 14.5 in. (36.8 cm)
  • Width: 1.25 in. (3.2 cm) (occupies a single, thin slot)
  • Depth: 17.5 in. (44.5 cm)
Environmental conditions
  • Storage temperature: -38° to 150° F (-40° to 70° C)
  • Operating temperature, nominal: 41° to 104° F (5° to 40° C)
  • Operating temperature, short-term: 23° to 131° F (-5° to 55° C)
  • Storage relative humidity: 5% to 95% relative humidity (RH)
  • Operating humidity, nominal: 5% to 85% RH
  • Operating humidity, short-term: 5% to 90% RH
  • Operating altitude: -60 to 4000 m
Compliance and agency approvals


  • UL 1950
  • CSA 22.2-No. 950
  • EN60950
  • IEC 60950 CB Scheme
  • ACA TS001
  • AS/NZS 3260


  • FCC CFR 47-PART 15 1998 Class A (up to 40 GHz)
  • ICES 003 Class A
  • AS/NZS 3548 Class A
  • EN55022-1998/EN50082-1 Class A
  • VCCI Class A
  • CISPR 22 Class A
  • BSMI/CNS 13438:1997 Class A
  • MSZEN55022
  • EN 300386-2/EN55022 Class B
  • EN61000-4-2:1995 Level 4
  • IEC61000-4-3:1995 ENV50140:1993 Level 3
  • IEC-1000-4-4 A/C Power Lines EFT Level 4
  • IEC-1000-4-4 D/C Power Lines EFT Level 4
  • IEC-1000-4-4 Signal Lines EFT Level 4
  • IEC-1000-4-5 A/C Power Line
  • IEC-1000-4-5 A/C Power
  • IEC-1000-4-5 D/C Power
  • IEC-1000-4-5 D/C Power
  • IEC-1000-4-5 Signal
  • IEC-1000-4-6 A/C Power Line Level
  • IEC-1000-4-6 D/C Power Line Level 3
  • IEC-1000-4-6 Signal Lines Level 3
  • IEC-1000-4-11 Voltage dips and sags

Network Equipment Building Systems (NEBS)

This product is designed to meet the following requirements (official qualification may be in progress):

  • SR-3580—NEBS: criteria levels (Level 3 compliant)
  • GR-63-Core—NEBS: physical protection
  • GR-1089-Core—NEBS: EMC and safety


  • ETS-300386-1
  • ETS-300386-2: 1997
  • ETS-300132-2:December 1994

Table 2   Supported SONET/SDH Alarm and Signal Events

Alarm/Signal SONET Description SDH Description

B1 BER Threshold Crossing Alarm

B1 BER Threshold Crossing Alarm


B2 BER Threshold Crossing Alarm

B2 BER Threshold Crossing Alarm


B3 BER Threshold Crossing Alarm

B3 BER Threshold Crossing Alarm


Line Alarm Indication Signal (AIS-L)

Multiplexer Section Alarm Indication Signal (MS-AIS)


Loss of Multiframe VT (LOM-V)

Loss of Multiframe (LOM)


Line Remote Defect Indication (RDI-L)

Multiplexer Section Remote Defect Indication (MS-RDI)


Path Alarm Indication Signal, or Alarm Indication Signal—Path (AIS-P)

Administrative Unit Alarm Indication Signal (AU-AIS)


Path Payload Label Mismatch, or Payload Label Mismatch—Path (PLM-P)

High Order Path Payload Label Mismatch (HP-PLM)


Path Loss of Pointer, or Loss of Pointer—Path (LOP-P)

Administrative Unit Loss of Pointer (AU-LOP)


Path Remote Defect Indication, or Remote Defect Indication—Path (RDI-P)

High Order Path Remote Defect Indication (HP-RDI)


Path Unequipped (UNEQ-P)

High Order Path Unequipped (HP-UNEQ)


Line BIP BER in excess of the Signal Degrade (SD) threshold

Multiplexer Section BIP BER in excess of the Signal Degrade (SD) threshold


Line BIP BER in excess of the Signal Fail (SF) threshold

Multiplexer Section BIP BER in excess of the Signal Fail (SF) threshold


Section Loss of Frame (LOF)

Regenerator Section Loss of Frame (LOF)


Section Loss of Signal (LOS)

Regenerator Section Loss of Signal (LOS)

Ordering Information

Description Part Number

Cisco 12000 Series Two-Port Channelized OC-3c/STM-1c (DS1/E1) Line Card—includes 128 MB default route memory with ECC


256 MB route memory upgrade option


Service and Support

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