1-Port HSSI Network Module

Feature Summary

The Cisco 3600 series 1-port high-speed serial interface (HSSI) network module provides full-duplex connectivity at Synchronous Optical Network (SONET) OC-1/STS-1 (51.840 Mhz), T3 (44.736 MHz), and E3 (34.368 MHz) rates in conformance with the EIA/TIA-612 and EIA/TIA-613 specifications. The actual rate of the interface depends on the external data service unit (DSU) and the type of service to which it is connected. This 1-port HSSI network module can reach speeds of up to 52 Mbps in unidirectional traffic with 1,548-byte packets and 4,250 packets per second. Asynchronous Transfer Mode (ATM), High-Level Data Link Control (HDLC), Point-to-Point Protocol (PPP), Frame Relay, and Switched Multi-Megabit Data Service (SMDS) WAN services are all fully supported.

Benefits

The 1-Port HSSI network module provides the following benefits:

Supports speeds up to 52 Mbps
Supports a range of connectivity options: ATM, Frame Relay, PPP, and SMDS
Supports EIA/TIA-612 and EIA/TIA-613 specifications at T3, E3, SONET OC1/STS-1 and NXT1 subrates

List of Terms

Asynchronous Transfer Mode (ATM)--International standard for cell relay in which multiple service types are conveyed in fixed-length (53-byte) cells. The fixed-length cells require lower processing overhead and allow higher transmission speeds than traditional packet switching methods.

Frame Relay--Standard switched data link layer protocol that handles multiple virtual circuits using HDLC encapsulation between connected devices. Frame Relay is generally considered to be a replacement for X.25.

High-Level Data Link Control (HDLC)--A standard bit-oriented synchronous data link layer protocol developed by the International Standards Organization (ISO). Derived from Synchronous Data Link Control (SDLC), HDLC specifies a data encapsulation method on synchronous serial links using frame characters and checksums.

High-Speed Serial Interface (HSSI)--A serial data communication interface providing high-speed serial connections (up to 52 Mbps in unidirectional traffic) over WAN links.

Point-to-Point Protocol (PPP)--Protocol that provides router-to-router and host-to-network connections over synchronous and asynchronous circuits.

Switched Multi-Megabit Data Service (SMDS)--A high-speed, connectionless data transmission service that provides wide area connectivity through the public telephone network.

T3--Digital WAN carrier facility. T3 transmits DS-3 formatted data at 44.736 Mbps through the telephone switching network.

Platforms

This feature is supported on the Cisco 3600 series routers.

Prerequisites

Before you configure the 1-port HSSI network module, complete the following prerequisite tasks:

Install the HSSI Network Module in a chassis slot. For information on how to install this network module, refer to the "Installing a 1-Port HSSI Network Module in a Chassis Slot" section in the 1-Port HSSI Network Module Configuration Note.
Complete basic device configuration, including host name, username, protocol, and security configuration. For more information about basic device configuration, refer to the Cisco 3620 Installation and Configuration Guide or the Cisco 3640 Installation and Configuration Guide.

Supported MIBs and RFCs

This feature supports the following MIB: OLD-CISCO-PLATFORM-MIB. For a description of this supported MIB and how to use it, see Cisco's MIB website on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

No RFCs are supported by this feature.

Configuration Tasks

Perform the tasks in the following sections to configure a HSSI interface. The first task is required; the remaining tasks are optional.

Specify a HSSI
Specify HSSI Encapsulation
Invoke ATM on a HSSI Line
Convert HSSI to Clock Master
Disable Fair Queueing

Specify a HSSI

To specify a HSSI and enter interface configuration mode, perform the following tasks in global configuration mode:

Task	Command
Begin interface configuration.	interface hssi slot/port

Specify HSSI Encapsulation

The HSSI supports the serial encapsulation methods, except for X.25-based encapsulations. The default method is HDLC. You can define the encapsulation method by performing the following task in interface configuration mode:

Task	Command
Configure HSSI encapsulation.	encapsulation {atm-dxi \| hdlc \| frame-relay \| ppp \| sdlc-primary \| sdlc-secondary \| smds \| stun}

For information about PPP, see the "Configure SLIP and PPP" chapter of the Cisco IOS Release 11.3 Access Services Configuration Guide and the "Configure PPP for Wide-Area Networking" chapter of the Cisco IOS Release 11.3 Wide-Area Networking Configuration Guide.

Invoke ATM on a HSSI Line

If you have an ATM DSU, you can invoke ATM over a HSSI line by mapping an ATM virtual path identifier (VPI) and virtual channel identifier (VCI) to a DXI frame address. ATM-DXI encapsulation defines a data exchange interface that allows a DTE (such as a router) and a DCE (such as an ATM DSU) to cooperate to provide a User-Network Interface (UNI) for ATM networks.

To invoke ATM over a serial line, perform the following tasks in interface configuration mode:

Task	Command
Specify the encapsulation method.	encapsulation atm-dxi
Map a given VPI and VCI to a DXI frame address.	dxi map protocol address vpi vci [broadcast]

Convert HSSI to Clock Master

You can convert the HSSI interface into a 45-MHz clock master by performing the following task in interface configuration mode:

Task	Command
Convert the HSSI interface into a 51.84-MHz clock master.	hssi internal-clock

Disable Fair Queueing

Disabling fair queuing will dramatically improve fast switching rates over the HSSI. To disable fair queueing, perform the following task in interface configuration mode:

Task	Command
Disable fair queueing.	no fair-queue

For more information about configuring HSSI interfaces, refer to the "Configuring Serial Interfaces" chapter in the Cisco IOS Release 11.3 Configuration Fundamentals Configuration Guide.

Configuration Examples

The following example shows how to configure a 1-port HSSI network module on a Cisco 3600 series router. Both sides of the network connection need to be configured:

interface hssi 0/0
 ip address 10.1.1.1 255.255.255.0
 hssi internal-clock
 no fair-queue
 no shutdown
interface hssi 1/0
 ip address 10.1.1.2 255.255.255.0
 hssi internal-clock
 no fair-queue
 no shutdown

In this example:

The interface hssi command specifies a HSSI interface and changes the configuration mode from global to interface.
The ip address command assigns an IP address to this interface.
The hssi internal-clock command sets the HSSI clock source.
The no fair-queue command disables fair queueing, which is enabled by default. This optimizes HSSI performance.
The no shutdown command enables the port.

Command Reference

There are no new or modified commands associated with this feature. All commands used with this feature are documented in the Cisco IOS Release 11.3 command references.

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