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Table of Contents
Configuring the Cisco uBR10-SRP-OC12SML DPT WAN CardCreating a DPT Ring
Understanding DPT Topology
Overview of the Intelligent Protection Switch Feature
Restrictions
Supported Platforms
Supported Standards, MIBs, and RFCs
Prerequisites
Configuration Tasks
Shutting Down the Interface
Performing a Basic Configuration
Adding a Node to a DPT Ring
Inserting the New Node
Enabling the New Node
Removing the Ring Wrap
Displaying a Summary of All Interfaces
Verifying the DPT WAN Card Configuration and Status
Displaying Hardware Information
Displaying the DPT Ring Topology
Displaying Packet Information
Displaying Intelligent Protection Switch Status
Command Reference
Glossary
Configuring the Cisco uBR10-SRP-OC12SML DPT WAN Card
UBR10-SRP-OC12SML, UBR10-SRP-OC12SML=
OL-2054-01 Rev. B0
January 14, 2002`
Feature History
| Release | Modification |
|
This Cisco uBR10-SRP-OC12SML DPT WAN Card was supported on the Cisco uBR10012 universal broadband router. |
This document describes the Cisco uBR10-SRP-OC12SML DPT WAN Card used in the Cisco uBR10012 chassis. This document provides the following information:
The Cisco uBR10012 Spatial Reuse Protocol (SRP) OC12 single-mode fiber, long reach (SML) dynamic packet transport (DPT) adapter card provides shared IP connectivity over SONET capability for the Cisco uBR10012 series router platform.
The Cisco uBR10-SRP-OC12SML DPT WAN card is a double-width card that requires two network uplink card slots in the Cisco uBR10012 chassis. If you are installing two adapter cards, they should be installed in slots 2/0 and 4/0 in the chassis. If you are installing only one adapter card, it can be installed in either slot 2/0, 3/0, or 4/0 in the chassis.
This section contains the following information:
Spatial Reuse Protocol Overview
Spatial Reuse Protocol (SRP) is a media-independent MAC layer protocol that operates over two counter-rotating fiber-optic rings. The dual rings provide survivability of data in case of a failed node or a break in connecting cables by rerouting the data path over the alternate ring.
The SRP dual-ring topology offers a number of advantages over other technologies, including minimal protocol overhead, statistical multiplexing, and support for priority traffic at the MAC layer. An SRP ring does not require a software-based station management transfer (SMT) protocol or the ring master negotiation that is used in other ring-based protocols.
SRP provides a more efficient use of bandwidth by having packets traverse only the part of the ring necessary to get to the destination node. Once the packet has reached the destination node, it is removed from the ring, allowing other parts of the ring to reuse the bandwidth. Because each ring node can source packets onto the ring concurrently, this maximizes ring bandwidth.
Data packets travel on one ring, while associated control packets travel in the opposite direction on the alternate ring, ensuring that the data takes the shortest path to its destination. (See Figure 1.)
Figure 1 DPT Ring
Each node on a DPT ring represents a Cisco uBR10012 router or another Cisco router using a similar OC12 DPT WAN card (such as a Cisco 12000 series Gigabit Switch Router (GSR), Cisco 7500 series router, or a Cisco uBR7246 VXR universal broadband router. A DPT ring can contain up to 32 nodes at one time, with each node holding a map of the ring topology that it continually updates to ensure that data takes the shortest path to its destination. The frequency of the updating can be manually configured.
The DPT interface uses the SONET ring architecture, which provides redundancy and protection from a failed node or fiber cut through the use of the Intelligent Protection Switch (IPS). When the DPT ring topology changes because of a node failure, as shown in Figure 2, the system software automatically puts the node into pass-through mode, where data continues to pass through the node, but the node is no longer seen on the ring topology map.
Figure 2 DPT Ring with a Node in Pass-Through Mode
In the event of a fiber cut, ring wraps are created to redirect data traffic over the alternate ring. In both pass-through mode and wrap mode, data packets not destined for the affected node still reach their destination. See Figure 3.
Figure 3 DPT Ring in Wrap Mode
Creating a DPT Ring
A DPT ring may contain as many as 32 nodes, or as few as 2 nodes. This section illustrates the layout and configuration of a simple three-node DPT ring.
Before the DPT ring can be created, each node (Cisco uBR10012 router or other Cisco router with a DPT port adapter) must have a DPT WAN card installed and configured. After the individual nodes are configured, the inner and outer rings of the DPT ring must be connected as shown in Figure 4.
Figure 4 Three-Node DPT Ring
To achieve this configuration, you must connect the DPT WAN cards as shown in Figure 5, being careful to observe the receive (RX) and transmit (TX) cable relationship.
Figure 5 Internodal Connections of a Three-Node DPT Ring
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Note Side A (RX outer/TX inner) of the DPT WAN card or port adapter must be connected to side B (TX outer/RX inner) of the DPT WAN card or port adapter in the next node in the ring. See the Cisco uBR10-SRP-OC12SML DPT WAN Card for the Cisco uBR10012 Series Router for more details on how to connect cables to the DPT WAN card. The location of the Side A and Side B connectors on other OC-12 port adapters might be different from those on the DPT WAN card. See the documentation for those other cards for details. |
Table 1 lists the internodal cable connections for a three-node DPT ring.
Table 1 Three-Node DPT Ring Cable Connections
| Internodal Cable Connections | |
|---|---|
| From Node/Connector | To Node/Connector |
Understanding DPT Topology
Every node on a DPT ring maintains a topology map of the ring so that it knows where to route traffic. It updates the topology map by periodically sending out a query, called a topology discovery packet, out onto the ring. Each node on the ring adds its own MAC address to the packet and resends the packet.
When the discovery packet returns to the originating node, the node uses the contents of the packet to update its node topology map. This ensures that each node has a real-time view of the DPT ring's topology and can respond quickly to any breaks in the ring.
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Tip You can use the srp topology-timer command to set the frequency with which the node sends out topology discovery packets. Use the show srp topology command is used to display the MAC addresses of each node on a DPT ring. |
Overview of the Intelligent Protection Switch Feature
The Intelligent Protection Switch (IPS) feature ensures that ring traffic flow continues uninterrupted even if device or ring failures occur. IPS protects the DPT ring by initiating ring wraps that route traffic in the opposite direction over the alternate ring.
The system software creates ring wraps by issuing an IPS request when failures are detected. Five different IPS requests are recognized. These five types of IPS requests are hierarchical, with higher-priority requests taking precedence over lower-priority requests.
Table 2 lists the types of IPS requests in order of priority.
| Request Priority | Request Type | Originator |
|---|---|---|
For example, if a signal failure was detected at the same time that an operator entered a manual switch request, the system would create the ring wrap at the point of signal failure, and the manual switch would be ignored.
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Tip The IPS feature is configured using the srp ips interface configuration commands, which are described in the documentation listed in the "Related Documents" section. |
Benefits
The Cisco uBR10-SRP-OC12SML DPT WAN card provides the following benefits:
- Accommodates large scale network topology. The adapter card is deployed in SONET OC-12 DPT rings. The DPT rings are connected to SONET Add Drop Multiplexers (ADMS) allowing the creation of small or very large rings. Each DPT ring supports a maximum of 64 nodes.
- Leverages fiber optics capacity at OC-12c line rates. The adapter card has two SC duplex ports. Each SC duplex port provides the physical connection to an adjacent device in a DPT ring.
- Provides a seamless way to upgrade existing Cisco uBR7200 series CMTS routers to high-performance Cisco uBR10012 routers with higher capacity OC-12 connections.
- Intelligent Protection Switching (IPS) for IP self-healing and restoration and for performance monitoring after a link or node failure.
- Supports single mode fiber transmissions.
- Allows data to obtain fair-shared access to the OC-12c rings.
- Controls the rate at which new packets are inserted on one or both rings simultaneously.
- Implements protection mechanisms, including wrap and unwrap, in the event of fiber or node failure.
- Substantially lower costs by eliminating a layer of SONET/SDH equipment.
- Flexibility that provides capabilities to serve as a common technology base for LAN, MAN, and WAN applications.
- Plug-and-play operations that avoid the extensive configuration and station management requirements of SONET/SDH Fiber.
- Extensive management information via the SONET/SDH Management Information Base (MIB) and MAC-layer source counters for network management and ring traffic engineering.
Restrictions
The Cisco uBR10-SRP-OC12SML DPT WAN card has the following restrictions.
If you are installing two DPT WAN cards, they must be installed in slots 2/0 and 4/0 in the chassis. If you are installing only one DPT WAN card, it can be installed in either slot 2/0, 3/0, or 4/0 in the chassis.
Related Features and Technologies
Dynamic Packet Transport—DPT is a packet ring technology designed to deliver scalable Internet service, reliable IP-aware optical transport, and simplified network operations. DPT-based solutions allow you to scale and distribute your Internet and IP services across a reliable optical packet ring infrastructure.
DPT is based on the Spatial Reuse Protocol (SRP), which is a Cisco-developed MAC-layer protocol. See the Dynamic Packet Transport (DPT) Feature Guide for more information.
Related Documents
The following documents describe the hardware components, installation, and cabling of the DPT WAN card and Cisco uBR10012 router:
The following documents describe the software configuration tasks and commands used to configure the DPT WAN card and Cisco uBR10012 router:
These documents are available on Cisco.com and the Customer Documentation CD-ROM.
Supported Platforms
This Cisco uBR10-SRP-OC12SML DPT WAN card is supported only on the Cisco uBR10012 universal broadband router.
Determining Platform Support Through Feature Navigator
Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Feature Navigator. Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.
Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image.
To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions at http://www.cisco.com/register .
Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Feature Navigator home page at the following URL:
Supported Standards, MIBs, and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
RFCs
Prerequisites
The Cisco uBR10-SRP-OC12SML DPT WAN card requires the following:
Configuration Tasks
See the following sections for configuration tasks for the Cisco uBR10-SRP-OC12SML DPT WAN card.
Enabling the Interface
Before using an interface, use the no shutdown command to enable the interface. Use the following procedure to enable an interface.
For complete descriptions of software configuration commands, refer to the publications listed in the "Related Documents" section.
Shutting Down the Interface
Before removing an interface, use the shutdown command to shut down (disable) the interface to prevent anomalies when you reinstall the new or reconfigured interface. When you shut down an interface, it is designated administratively down in the show command displays.
Use the following procedure to shut down an interface.
For complete descriptions of software configuration commands, refer to the publications listed in the "Related Documents" section.
Performing a Basic Configuration
This section describes guidelines for performing a basic configuration of the DPT WAN card, which includes enabling the DPT WAN card, configuring the IP address, and specifying IP routing. You might also need to enter other configuration subcommands, depending on the requirements for your system configuration and the protocols you plan to route on the interface.
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Tip After configuring the DPT WAN card, see the "Adding a Node to a DPT Ring" section for adding the router to a DPT ring. |
Use the following procedure to initially configure the DPT WAN card.
After you have completed your configuration, you can check it using show commands. For an explanation of the relevant show commands, see the "Monitoring and Maintaining the DPT WAN Card" section.
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Note For detailed information about the DPT WAN card configuration commands, see the publications listed in the "Related Documents" section. |
Adding a Node to a DPT Ring
This section describes how to install and configure a Cisco uBR10012 router with a DPT WAN card as a node in the DPT ring. Before proceeding, verify that you have successfully installed and configured a DPT WAN card in the Cisco uBR10012 router, as described in the "Performing a Basic Configuration" section.
To add a node to a DPT ring, you must perform the following procedures in the order given:
The following sections describe the commands needed for each procedure. For the purposes of this section, the new node (the Cisco uBR10012 router with the DPT WAN card) is being inserted between Node A and Node D, as shown in Figure 6:
Figure 6 DPT Ring Topology with Four Nodes
Forcing a Ring Wrap to Create a Break in the DPT Ring
To add a node to a DPT ring, you must first reroute the traffic flow around the break where the new node is to be inserted. This is done by using the srp ips forced-switch command to force a ring wrap at that point. Use the following procedure on Node A to force a ring-wrap between Node A and Node D, as given in Figure 6.
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Note You can add a node to a DPT ring without entering the srp ips forced-switch command, but you then cannot control when the traffic is rerouted and restored; the system determines the time instead. |
| Command | Purpose | |
|---|---|---|
| Step 1 |
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| Step 2 |
Enter interface configuration mode for the DPT WAN card on Node A, where x/0/0 identifies the appropriate slot number. |
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| Step 3 |
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| Step 4 |
After completing this procedure, the DPT ring topology changes, as shown in Figure 7:
Figure 7 DPT Ring with Ring Wraps Created by a Forced Switch
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Tip Use the command show srp topology to verify that the ring wraps are in place. See the "Monitoring and Maintaining the DPT WAN Card" section. |
Inserting the New Node
After forcing a ring wrap in the DPT ring to create a break for the new node, you must then insert the new node (the Cisco uBR10012 router with the DPT WAN card) into the DPT ring, as shown in Figure 8.
Figure 8 DPT Ring Topology with an Added Node
Use the following procedure to insert the new node (Node E, the Cisco uBR10012 router with the DPT WAN card) into the DPT ring.
Step 1 Disconnect the fiber-optic cables connecting side A of node A to side B of node D.
Step 2 Connect side A of node A to side B of the new node (node E, the Cisco uBR10012 router), using two simplex or one duplex fiber-optic cable. Connect side A of Node E to side B of node D.
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Note Whenever you are adding nodes to the ring, connect the cables by carefully observing the receive (Rx) and transmit (Tx) cabling relationship. The labels under the fiber connectors identify side A, Tx and Rx, and side B, Tx and Rx. Be sure to connect the fiber-optic cables using the receive (Rx) and transmit (Tx) cabling relationship, so that you always connect an Rx port on one SRP line card to a Tx port on the next SRP line card. Side A has outer ring receive fiber, and side B has inner ring receive fiber. Side A must be connected to side B of the adjacent node in the ring and vice versa. |
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Tip Be careful to observe the proper cable orientation. When using duplex cables, you must reverse one of the cable ends for correct orientation. For complete information on cabling, see the Cisco uBR10-SRP-OC12SML DPT WAN Card for the Cisco uBR10012 Series Router document. |
Step 3 If the DPT WAN card in the new router (node E) has not been configured, do so at this time. See the "Performing a Basic Configuration" section.
Enabling the New Node
After inserting and cabling the new node into the DPT ring, enable the DPT WAN card on the new node (node E), using the following procedure.
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Tip Use the command show srp topology to verify that the ring wraps are in place. See the "Monitoring and Maintaining the DPT WAN Card" section. |
Removing the Ring Wrap
The final step in inserting a new node is to remove the ring wrap on node A. Use the following procedure on node A to remove the ring wrap and to start passing traffic through the new node (node E, the Cisco uBR10012 router).
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Tip Use the command show srp topology to verify that the ring wraps are in place. See the "Monitoring and Maintaining the DPT WAN Card" section. |
Removing a Node from a DPT Ring
Use the following procedure to remove an existing node from a DPT ring. This procedure assumes you are removing node D from the DPT ring shown in Figure 9.
Figure 9 DPT Ring Topology with Four Nodes
Step 1 Isolate node D by entering the srp ips request forced-switch a command on the node A router, and the srp ips request forced-switch b command on the node C router. For example, if node A is a Cisco uBR10012 router with a DPT WAN card in slot 2/0, you would issue the following commands:
If node C is a Cisco uBR10012 router with a DPT WAN card in slot 4/0, you would issue the following commands:
Step 2 Enter the show srp topology command on either router to verify that the ring wraps are in place and that node D no longer exists on the ring. (See the "Monitoring and Maintaining the DPT WAN Card" section.)
Step 3 Disconnect both ends of the cable connecting side A of node D to side A of node C.
Step 4 Disconnect the cable connected to side B of node D and connect it to side B of node C.
Step 5 Remove the two ring wraps created by the forced switch on nodes A and C by entering the no srp ips request forced-switch a command on node A, and no srp ips request forced-switch b command on node C.
Step 6 Enable IP routing by entering the ip routing command to restart data traffic across the DPT ring.
Monitoring and Maintaining the DPT WAN Card
The following sections describe the different show commands that provide information about the status and operation of the Cisco uBR10-SRP-OC12SML DPT WAN card.
- Displaying Version Information
- Displaying a Summary of All Interfaces
- Verifying the DPT WAN Card Configuration and Status
- Displaying Hardware Information
- Displaying the DPT Ring Topology
- Displaying Packet Information
- Displaying Intelligent Protection Switch Status
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Note For complete descriptions of the commands shown in the following sections, see the publications listed in the "Related Documents" section. |
Displaying Version Information
To display the version of Cisco IOS software being run, as well as a list of interfaces that are installed and recognized, use the show version command:
Displaying a Summary of All Interfaces
To display a summary of all interfaces, including the DPT WAN card, use the show ip interface brief command in privileged EXEC mode:
Verifying the DPT WAN Card Configuration and Status
To verify the DPT WAN card's configuration, including whether an interface is up or shut down, use the show interfaces command. The following example shows a typical display for a DPT WAN card that is up and online:
The following example shows a typical display when the DPT WAN card has been disabled with the shutdown command:
Another quick way of displaying a card's status is with the show protocols command:
Displaying Hardware Information
To display hardware information about the DPT WAN card, use the show diag and the show controllers srp commands. The following is a typical display for the show diag command for a DPT WAN card:
The following is an excerpt of a typical display for the show controllers srp details command for a DPT WAN card:
Displaying the DPT Ring Topology
To display the topology of the DPT ring, use the show srp topology command. The following is a typical display for a Cisco uBR10012 router with two DPT WAN cards installed in slots 2/0 and 4/0. The key components of the display are the list of nodes in the DPT ring, the frequency of the topology discovery packets, the time that a topology discovery packet was last received, and the time that the topology of the DPT ring actually changed.
The following shows a DPT ring where ring wrap has occurred, indicating a possible break in the cabling between nodes 2 and 3:
The following display shows that the interface has not received a topology discovery packet for 2 days and 18 hours. This was also the time that the last topology change occurred, which indicates that this node might have been isolated from the DPT ring, either due to a break in the fiber optics cabling or by a forced ring wrap.
Displaying Packet Information
You can count the number of packets from a specific MAC address with the srp count interface configuration command. You can then display the number of packets received or rejected with the show srp source-counters command. For example:
Displaying Intelligent Protection Switch Status
To display the current IPS status, use the show srp ips command:
The following shows a DPT WAN card with a wrapped interface:
Configuration Examples
This section provides typical sample configurations for the Cisco uBR10-SRP-OC12SML DPT WAN card. The following is a portion of the configuration file for the Cisco uBR10012 router with two DPT WAN cards that are configured with an IP address but otherwise left with their default configurations:
The following is a portion of the configuration file for a DPT WAN card that has been configured with non-default values for the SRP interface parameters:
Command Reference
This section summarizes the interface configuration commands used to configure and monitor the Cisco uBR10-SRP-OC12SML DPT WAN card. Table 3 lists the parameter, the interface configuration command used to alter it, and the default value of the parameter.
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Note For complete information on these commands, see the software documents listed in the Related Documents. |
Table 3 DPT Adapter Interface Configuration Default Values
Glossary
- ADM—Add Drop Multiplexer. Device used to add or drop virtual channels from SONET/SDH into physical tributaries that connect across the ring.
- DCC—Data Country Code.
- IPS—Intelligent Protection Switch.
- ITU-T—International Telecommunication Union Telecommunication Standardization Sector (formerly the Consultative Committee for International Telegraph and Telephone [CCITT]).
- MAC—Media Access Control.
- MIB—Management Information Base.
- OC-3/STM-1, OC-12c/STM-4c, OC-48c/STM-16c, and so on—Optical Carrier specifications for SONET OC and SDH STM transmission rates.
- OC-N—SONET multiplexing measure: Optical Carrier Level N, where N indicates the number of 51.84 megabit per second channels.
- OC-Nc/STM-Nc—Designation in which a lowercase c after N indicates that N channels are concatenated into one logical channel having a bandwidth of N multiplied by the appropriate rate for SONET and SDH. For SONET N is defined as having the values 3, 12, 48, and 192; for SDH, the legal values are 1, 4, and 16.
- SDH—Synchronous Digital Hierarchy. International standard for optical digital transmission at hierarchical rates from 155.520 Mbps (STM-1) to 2.488 gigabits per second (Gbps) (STM-16) and higher.
- SONET—Synchronous Optical Network. An American National Standards Institute (ANSI) standard (T1.1051988) for optical digital transmission at hierarchical rates from 51.840 Mbps (OC-1) to 2.488 Gbps (OC-48) and higher.
- SRP—Spatial Reuse Protocol. A Layer 2 MAC protocol for use with SONET and SDH rings that runs over a dual-ring network topology and is characterized by shared media, statistical multiplexing, global fairness, and spatial reuse.
- STM-N—Synchronous Transport Module Level N. SDH multiplexing measure, where N indicates the number of 155.52 Mbps channels.
