Table of Contents
OC-12c Dynamic Packet Transport Port Adapter for the 7200 RouterFeature Overview
Supported Platforms
Supported Standards, MIBs, and RFCs
Prerequisites
Configuration Tasks
Configuration Examples
Command Reference
srp buffer-size
srp deficit-round-robin
srp loopback
srp priority-map
srp random-detect
srp shutdown
srp tx-traffic-rate
Glossary
OC-12c Dynamic Packet Transport Port Adapter for the 7200 Router
This feature module describes the OC-12c Dynamic Packet Transport Port Adapter (DPT) feature.
This document includes the following sections:
Feature Overview
The dual-width OC-12c Dynamic Packet Transport (DPT) port adapter is available on Cisco 7200 series routers and Cisco 7200 VXR series routers. The DPT is an OC-12c interface used in Cisco 7200 series and Cisco 7200 VXR routers to provide a shared IP over SONET capability.
The following benefits are offered by the DPT for the Cisco 7200 and Cisco 7200 VXR series routers:
Related Documents
For related information on this feature, refer to the following document:
Supported Platforms
Supported Standards, MIBs, and RFCs
MIBs
RFCs
Standards
Prerequisites
The DPT is compatible with any Cisco 7200 series router equipped with the correct Route Switch Processor (RSP2 or RSP4), running Cisco IOS Release 12.0(6)S or later.
Configuration Tasks
See the following sections for configuration tasks for the DPT interface. Each task in the list indicates if the task is optional or required.
For information on other configuration tasks for the DPT port adapter, refer to the "Configure an Ethernet" section in the "Configuring Interfaces" chapter of the Configuration Fundamentals Configuration Guide.
For information on other commands that can be used by the DP interface, refer to the Cisco IOS Release 12.0 configuration guides.
Configuring the Dynamic Packet Transport Interface
| 1SRP= Spatial Reuse Protocol |
The system displays an OK message when the configuration has been stored.
Verifying DPT
Step 1 Use the show running-config command to display the currently running configuration. The example below shows that the current software version is 12.0(8)S, a DPT is installed (the DPT is shown as interface SRP1/0), and the IP address of the DPT:
Step 2 Use the show version command to display the configuration of the system hardware and Cisco IOS software information. The following example shows that the Cisco IOS version is 12.0(8)S and a DPT is installed:
Configuring Intelligent Protection Switching
The SRP interface uses ring architecture to provide redundancy and protection from a failed node or fiber cut through the use of Intelligent Protection Switching (IPS). The tasks described in this section are optional.
Verifying Intelligent Protection Switching
Use the show srp command to determine whether an intelligent protection switch is enabled or idle:
Configuring 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 a query, called a topology discovery packet, out onto the outer-ring path. Each node on the ring adds its own MAC address to the packet. When the discovery packet returns to the originating node, the contents of the packet are used to update the topology map. You use the srp topology-timer command to set the frequency with which the node sends out topology discovery packets.
Verifying DPT Topology
Use the show srp topology command to show the identity of the nodes on the DPT ring according to their MAC addresses. The following example shows a three-node DPT ring.
Configuration Examples
This section provides the following configuration examples:
DPT Port Adapter
In the following example, the OC-12c DPT SRP interface is specified and the IP address and subnet mask is assigned to the interface.
IPS
In the following example the SRP IPS options are configured:
DPT Topology
In the following example, the identity of the nodes on the DPT ring according to their MAC addresses is shown. The following example shows a three-node DPT ring. Nodes 0 and 2 are wrapped:
Command Reference
This section documents new commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command reference publications.
The SRP interface provides commands to enforce quality of service (QoS) functionality on the transmit side and receive side of Cisco routers. SRP uses the IP type of service (ToS) field values to determine packet priority.
On the transmit side the SRP interface classifies traffic into high- and low- priority traffic. High- priority traffic is rate shaped and has higher priority than low-priority traffic. The user has the option to configure high- or low-priority traffic and can rate limit the high-priority traffic.
srp buffer-size
To make adjustments to buffer settings on the receive side for different priority traffic, use the srp buffer-size interface configuration command. Use the no form of this command to disable buffer size configurations.
- srp buffer-size receive [high | medium]
- no srp buffer-size receive [high | medium]
Syntax Description
|
Allocates synchronous dynamic random-access memory (SDRAM) buffer for incoming packets. |
|
|
Buffer size for high- or medium-priority packets. Any number from 16 to 8192 in bytes. |
Defaults
high = 4096 kbytes, medium = 4096 kbytes, low = 8192 kbytes.
Command History
Examples
The following example shows the buffer size for the receive side at the high setting of 17 kbytes:
Related Commands
| Command | Description |
|---|---|
| 1MTU = maximum transmission unit |
srp deficit-round-robin
To transfer packets from the internal receive buffer to IOS, use the srp deficit-round-robin configuration command. Use the no form of this command to disable srp deficit-round-robin.
- srp deficit-round-robin [input | output] [quantum | deficit]
- no srp deficit-round-robin
Syntax Description Syntax Description
|
DRR quantum value. Any number from 9216 to 32767. The default is 9216. |
|
|
DRR deficit value. Any number from 0 to 65535. The default is 16384. |
Defaults
quantum = 9216, deficit = 16384Command Modes
Command History
Command History Command History
Examples
The following example shows packets configured for the high-priority input queue:
Related Commands Related Commands
srp loopback
To loop the SRP interface on a OC-12c DPT, use the srp loopback interface configuration command. Use the no form of this command to remove the loopback.
- srp loopback {internal | line} {a | b}
- no srp loopback
Syntax Description Syntax Description
|
Sets the loopback toward the network before going through the framer (internal), or loops the payload data toward the network (line). |
|
Defaults Defaults
Command Modes
Command History
Command History mmand History
Usage Guidelines
Use this command for troubleshooting purposes.
Examples
The following example configures the loopback test on the a side of the SRP interface:
srp priority-map
To set priority mapping for transmitting and receiving packets, use the srp priority-map configuration command. Use the no form of this command to disable priority mapping.
- srp priority-map {receive} {high | medium | low}{transmit}{high | medium}
- no srp priority-map
Syntax Description
|
Mapping for high- or medium-priority packets. Range is between 1 and 8. |
|
|
Specifies mapping for low-priority packets on the receive side. |
Defaults
receive high = 5, receive medium = 3, transmit = 7
Command Modes
Command History
Usage Guidelines
The SRP interface provides commands to enforce quality of service (QoS) functionality on the transmit side and receive side of Cisco routers. SRP uses the IP type of service (ToS) field values to determine packet priority.
The SRP interface classifies traffic on the transmit side into high- and low-priority traffic. High-priority traffic is rate shaped and has higher priority than low-priority traffic. You have the option to configure high- or low-priority traffic and can rate limit the high-priority traffic.
The command srp priority-map transmit enables the user to specify IP packets with <tos-value> and above to be considered as high-priority traffic.
On the receive side, when WRED is enabled, SRP hardware classifies packets into high-, medium-, and low-priority packets based on IP ToS value. After classification, it stores the packet into the internal receive buffer. The receive buffer is partitioned for each priority packet. Cisco routers can employ WRED based on the IP ToS value. Routers also employ the Deficit Round Robin (DRR) algorithm to transfer packets from the internal receive buffer to IOS.
The command srp priority-map receive enables the user to classify packets as high, medium, or low based on the IP ToS value.
Examples
The following example configures the Cisco 7200 series routers to transmit packets with priority greater than 5 as high priority packs:
Related Commands Related Commands
srp random-detect
To configure WRED parameters on packets received through an SRP interface, use the srp random-detect interface configuration command. Use the no form of this command to return the value to the default.
- srp random-detect [enable | compute-interval | input | precedence]
- no srp random-detect
Syntax Description Syntax Description
Defaults
Command Modes
Interface configuration command
Command History
Examples
The following example has configured WRED parameters on packets received through an SRP interface with a weight factor of 5:
srp shutdown
To disable the SRP interface, use the shutdown interface configuration command. To restart a disabled interface, use the no form of this command.
- srp shutdown [a | b]
- no srp shutdown [a | b]
Syntax Description Syntax Description
Defaults
Command Modes
Command History
Usage Guidelines
The srp shutdown command disables all functions on the specified interface.
Examples
The following example turns off the A side of the SRP interface:
srp tx-traffic-rate
To limit the amount of high-priority traffic that the SRP interface can handle, use the srp tx-traffic-rate configuration command. Use the no form of this command to disable transmitted traffic rate.
- srp tx-traffic number
- no srp tx-traffic number
Syntax Description Syntax Description
Defaults
Command Modes
Command History
Examples
The following example shows SRP transmitted traffic transmitting at 1000 kilobits per second:
Glossary
IPS—Intelligent Protection Switching.
MTU—Maximum Transmission Unit.
SDRAM—Synchronous Dynamic Random-access Memory.
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 DPT, 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.
WRED—Weighted Random Early Detection.