Table Of Contents

Configuring the DPTIP

Using the EXEC Command Interpreter

Configuring the DPTIP Interface

Shutting Down the Interface

Performing a Basic Configuration

Configuring the Intelligent Protection Switch Feature

Configuring the DPT Topology Feature

Changing the Default Values of Configuration Parameters

Using show Commands to Check System Status

Creating a DPT Ring

Adding or Removing Nodes in a DPT Ring

Adding a Node to a DPT Ring

Removing a Node from a DPT Ring

Checking the Configuration

Using show Commands to Verify the New Interface Status

Using the ping Command to Verify Network Connectivity

Configuring the DPTIP

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To continue your DPTIP installation, you must configure the DPTIP interface.

This chapter contains the following sections:

• Using the EXEC Command Interpreter

• Configuring the DPTIP Interface

• Checking the Configuration

Using the EXEC Command Interpreter

You modify the configuration of your router through the software command interpreter called the EXEC (also called enable mode). You must enter the privileged level of the EXEC command interpreter with the enable command before you can use the configure command to configure a new interface or change the existing configuration of an interface. The system prompts you for a password if one has been set.

The system prompt for the privileged level ends with a pound sign (#) instead of an angle bracket (>). At the console terminal, use the following procedure to enter the privileged level:

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Step 1 At the user-level EXEC prompt, enter the enable command. The EXEC prompts you for a privileged-level password as follows:

Router> enable
Password:


Step 2 Enter the password (the password is case sensitive). For security purposes, the password is not displayed.

When you enter the correct password, the system displays the privileged-level system prompt (#):

Router#




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To configure the new interface, proceed to the "Configuring the DPTIP Interface" section.

Configuring the DPTIP Interface

After you verify that the new DPTIP is installed correctly (the enabled LED goes on), use the privileged-level configure command to configure the new interface. Have the following information available:

•IP addresses, if you plan to configure the interface for IP routing

•Bridging protocols you plan to use

If you installed a new DPTIP or if you want to change the configuration of the existing interface, you must enter configuration mode to configure the new interface. If you replaced a DPTIP that was previously configured, the system recognizes the new interfaces and brings each of them up in their existing configuration.

For a summary of the configuration options available and instructions for configuring a DPTIP, refer to the appropriate configuration publications listed in the "Related Documentation" section on page vi.

You execute configuration commands from the privileged level of the EXEC command interpreter, which usually requires password access. Contact your system administrator, if necessary, to obtain password access. (See the "Using the EXEC Command Interpreter" section for an explanation of the privileged level of the EXEC.)

This section contains the following subsections:

• Shutting Down the Interface

• Performing a Basic Configuration

• Configuring the Intelligent Protection Switch Feature

• Configuring the DPT Topology Feature

• Checking the Configuration

Shutting Down the Interface

Before you remove an interface that you will not replace, 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.

Follow these steps to shut down an interface:

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Step 1 Enter the privileged level of the EXEC command interpreter (also called enable mode). (See the "Using the EXEC Command Interpreter" section for instructions.)

Step 2 At the privileged-level prompt, enter configuration mode and specify that the console terminal is the source of the configuration subcommands, as follows:

Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#




Step 3 Shut down the interface by entering the interface srp subcommand (followed by the interface address of the interface), and then enter the shutdown command. Table 4-1 shows the command syntax.

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Note The interface type of the DPTIP is srp.

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When you have finished, press Ctrl-Z—hold down the Control key while you press Z—or enter end or exit to exit configuration mode and return to the EXEC command interpreter.

Table 4-1 Syntax of the shutdown Command 

Platform	Command	Example
Cisco 7500 series routers	interface, followed by the type (srp) and slot/port adapter/port (interface-processor-slot-number/ port-adapter-slot-number interface-port-number)	The example shows the DPTIP interface in interface processor slot 1 being shut down. Router(config-if)# interface srp 1/0/0 Router(config-if)# shutdown Ctrl-Z Router#

Step 4 Write the new configuration to NVRAM as follows:

Router# copy running-config startup-config [OK] Router#




The system displays an OK message when the configuration has been stored in NVRAM.

Step 5 Verify that new interfaces are now in the correct state (shut down) using the
show interfaces command (followed by the interface type and interface address of the interface) to display the specific interface. Table 4-2 provides examples.

Table 4-2 Example of the show interfaces Command 

Platform	Command	Example
Cisco 7500 series routers	show interfaces srp, followed by slot/port adapter/port (interface-processor-slot-number/ port-adapter-slot-number/ interface-port-number)	The example is for interface 0 on an interface processor in interface processor slot 1. Router# show interfaces srp 1/0/0 srp 1/0/0 is administratively down, line protocol is down [Additional display text omitted from this example]

Step 6 Reenable interfaces by doing the following:

a. Repeat Step 3 to reenable an interface. Substitute the no shutdown command for the shutdown command.

b. Repeat Step 4 to write the new configuration to memory.
Use the copy running-config startup-config command.

c. Repeat Step 5 to verify that the interfaces are in the correct state. Use the
show interfaces command followed by the interface type and interface address of the interface.

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For complete descriptions of software configuration commands, refer to the publications listed in the "Related Documentation" section on page vi.

Performing a Basic Configuration

This section describes guidelines for performing a basic configuration: enabling the DPT port adapter 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. After configuring the DPTIP in a Cisco 7500 series router, see the "Adding a Node to a DPT Ring" section for adding the router to a DPT ring.

Before using the configure command, you must enter the privileged level of the EXEC command interpreter with the enable command. The system prompts you for a password if one has been set.

Use the following procedure to configure the DPTIP. Press the Return key after each configuration step, unless otherwise noted.

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Step 1 Confirm that the system recognizes the DPTIP by entering the show running-config command:

Router# show running-config




For an example of output from the show running-config command, see the "Using show Commands to Check System Status" section.

Step 2 Enter configuration mode and specify that the console terminal is the source of the configuration subcommands:

Router# configure terminal




Step 3 Enable IP routing by entering the ip routing command:

Router(config)# ip routing




Step 4 At the prompt, specify the new interface to configure by entering the interface command, followed by the type (srp) and slot/port adapter/port. The example that follows is for a DPTIP in slot 1:

Router(config)# interface srp 1/0/0




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Note The interface type of the DPTIP is srp.

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Step 5 Assign an IP address and subnet mask to the interface with the ip address configuration subcommand, as in the following example:

Router(config)# interface srp 1/0/0 Router(config-if)# ip address 10.1.2.3 255.0.0.0




Step 6 Use the srp framing command to verify that the framing is set to SONET for both side A and side B. The example below shows framing being set to SONET on side B of the DPTIP in slot 1:

Router(config)# interface srp 1/0/0 Router(config-if)# srp framing sonet side b




Step 7 Use the srp clock-source internal command to set the clock source to internal for both sides of the DPTIP. The example below shows side A being set to internal:

Router(config)# interface srp 1/0/0 Router(config-if)# srp clock-source internal side a




Step 8 Change the shutdown state to up and enable the interface:

Router(config)# interface srp 1/0/0 Router(config-if)# no shutdown




The no shutdown command passes an enable command to the DPTIP. It also causes the DPTIP to configure itself based on the previous configuration commands that were sent.

Step 9 Add any other configuration subcommands required to enable routing protocols and adjust the interface characteristics.

Step 10 When you have included all of the configuration subcommands to complete the configuration, enter ^Z (press the Control key while you press Z) to exit configuration mode.

Step 11 Write the new configuration to memory:

Router# copy running-config startup-config




The system displays an OK message when the configuration has been stored.

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After you have completed your configuration, you can check it using show commands. For an explanation of show commands, see the "Using show Commands to Check System Status" section.

Configuring the Intelligent Protection Switch Feature

Intelligent Protection Switch (IPS) 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. The five types of IPS requests are hierarchical, with higher-priority requests taking precedence over lower-priority requests. 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. Table 4-3 lists the types of IPS requests in order of priority.

Table 4-3 IPS Request Hierarchy

Request Type	Originator
1 Forced switch	Operator
2 Signal fail	Software
3 Signal degrade	Software
4 Manual switch	Operator
5 Wait to restore	Software

When you add a node to a DPT ring, you must create a break in the ring. You can create the break by initiating a forced switch request using the srp ips request command. See the "Adding a Node to a DPT Ring" section. The following example shows a forced switch request on side A of the DPTIP:

Router(config)# interface srp 2/0/0 Router(config-if)# srp ips request fs side A




If you need more detailed information about IPS commands, refer to publications listed in the
"Related Documentation" section on page vi.

Configuring the DPT Topology Feature

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 ring. 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 node topology map. You use the srp topology-timer command to set the frequency with which the node sends out topology discovery packets.

The show srp topology command is used to display the MAC addresses of each node on a DPT ring. See the "Using show Commands to Check System Status" section.

If you need more detailed information about DPT topology commands, see the "Related Documentation" section on page vi.

Changing the Default Values of Configuration Parameters

The default values of the DPTIP configuration parameters can be changed to match your network requirements. Table 4-4 lists the configuration parameter, the command used to alter it, and the default value of the parameter. If you need more detailed configuration information, refer to the publications listed in the "Related Documentation" section on page vi.

Table 4-4 DPTIP Configuration Default Values 

Parameter	Configuration Command	Default Value
Maximum transmission unit (MTU)	mtu bytes	9000 bytes
Buffer size	srp buffer-size bytes	h = 4096 kbytes, m = 4096 kbytes, l = 8192 kbytes
Count	srp count 48-bit source address in hexadecimal format H.H.H.	—
Deficit round robin	srp deficit-round-robin	quantum = 9216, deficit = 16384
Flag	srp flag [c2 value] [j0 value] [s1s0 value]	c2 set to 0x16; j0 set to 0xcc;s1s0 set to 0
Framing	srp framing [sdh | sonet]	SONET OC-12c
Internal clock	srp clock-source [internal | line] [a | b]	Internal
IPS	srp ips [request | timer | wtr-timer]	timer = 1 sec, wtr-timer = 60 sec
Loopback	srp loopback [internal | line] [a | b]	—
Priority map	srp priority-map [receive | transmit]	receive high = 5, receive med = 3, transmit = 7
Random-detect	srp random-detect [compute-interval | input | precedence]	compute interval = 128 sec
Reject	srp reject 48-bit source address in hexadecimal format H.H.H.	—
Shutdown	srp shutdown [a | b]	—
Topology timer	srp topology-timer value in seconds	5 sec
TX traffic rate	srp tx-traffic-rate rate in kbps	10,000 kbps

Using show Commands to Check System Status

The system maintains different kinds of information about its configuration and system status. This information can be accessed by using the show commands. This section contains show command information relevant to the installation and configuration of the DPTIP. See the "Related Documentation" section on page vi to locate more detailed information on show commands.

This section contains examples of the following commands:

•show running-config

•show version

•show protocols

•show diag

•show controllers srp

•show interfaces srp

•show srp ips

•show srp topology

•show srp source-counters

Use the show running-config command to display the currently running configuration. The example below shows that the current software version is Cisco IOS Release 12.0(6)S, a DPTIP is installed (the DPTIP is shown as interface SRP1/0/0), and the IP address of the DPTIP is 192.168.0.20 255.255.255.0:

Router# show running-config Building configuration... Current configuration: version 12.0(6)S service timestamps debug uptime service timestamps log datetime no service password-encryption service udp-small-servers service tcp-small-servers ! hostname uut2 ! ip subnet-zero ip host abrick 192.168.254.254 ip host curly 192.168.1.20 ip host sink 192.168.1.30 ip host sneha 192.168.1.40 ip name-server 192.168.2.132 ! ! ! interface SRP1/0/0 mac-address 0010.5555.6666 ip address 192.168.0.20 255.255.255.0 no ip directed-broadcast no ip route-cache cef no ip route-cache distributed no keepalive no srp random-detect input high no srp random-detect input medium no srp random-detect input low




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(6)S, and the DPTIP is shown as 1 VIP2 R5K controller (1 SRP):

Router# show version Cisco Internetwork Operating System Software IOS (tm) RSP Software (RSP-JV-M), Version 12.0(19981112:225526) [iks-srppa 236] Copyright (c) 1986-1998 by cisco Systems, Inc. Compiled Fri 04-Dec-98 12:59 by iks Image text-base:0x600108F8, data-base:0x60E72000




ROM:System Bootstrap, Version 12.0(6)S(2) [nitin 2], RELEASE SOFTWARE (fc1) BOOTFLASH:GS Software (RSP-BOOT-M), Version 11.1(8)CA, router uptime is 2 days, 21 hours, 7 minutes System restarted by reload System image file is "tftp://223.255.254.254/muck/karthiks/rsp-jv-mz"




cisco RSP2 (R4700) processor with 65536K/2072K bytes of memory. R4700 processor, Implementation 33, Revision 1.0 Last reset from power-on G.703/E1 software, Version 1.0. G.703/JT2 software, Version 1.0. X.25 software, Version 3.0.0. SuperLAT software (copyright 1990 by Meridian Technology Corp). Bridging software. TN3270 Emulation software. 1 EIP controller (4 Ethernet). 1 VIP2 R5K controller (1 SRP). 4 Ethernet/IEEE 802.3 interface(s) 123K bytes of non-volatile configuration memory.




20480K bytes of Flash PCMCIA card at slot 0 (Sector size 128K). 8192K bytes of Flash internal SIMM (Sector size 256K). No slave installed in slot 7. Configuration register is 0x0




WARNING:Chassis Interface not present




Use the show protocols command to show whether a DPTIP is up, as shown in the following example:

router# show protocols Global values: Internet Protocol routing is enabled Ethernet0/0/0 is up, line protocol is up Internet address is 192.168.6.2/16 Ethernet0/0/1 is administratively down, line protocol is down Internet address is 192.168.0.1/8 Ethernet0/0/2 is up, line protocol is down Ethernet0/0/3 is administratively down, line protocol is down SRP2/0/0 is up, line protocol is up Internet address is 192.168.0.40/8




Use the show diag command to view system hardware information. The following example shows a DPTIP installed in slot 0:

Router# show diag 0 Slot 0: Physical slot 0, ~physical slot 0xF, logical slot 0, CBus 0 Microcode Status 0x4 Master Enable, LED, WC Loaded Board is analyzed Pending I/O Status:None EEPROM format version 1 VIP2 R5K controller, HW rev 2.01, board revision B0 Serial number:06741587 Part number:73-2167-03 Test history:0x0 RMA number:00-00-00 Flags:cisco 7000 board; 7500 compatible




EEPROM contents (hex): 0x20:01 1E 02 01 00 66 DE 53 49 08 77 03 00 00 00 00 0x30:58 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00




Slot database information: Flags:0x4 Insertion time:0x15FC (2d21h ago)




Controller Memory Size:32 MBytes DRAM,4096 KBytes SRAM




PA Bay 0 Information: SRP PA,1 port,PA-SRP-MM EEPROM format version 1 HW rev 1.00, Board revision UNKNOWN Serial number:00000000 Part number:73-3250-01

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Note If you do not designate the slot number with the show diag command, hardware information for all slots is displayed.

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Use the show controllers srp command to display the location of the DPTIP and other configuration information specific to the DPTIP, as shown in the following example:

Router# show controllers srp




SRP2/0/0 SRP2/0/0 - Side A (Outer RX, Inner TX) SECTION LOF = 2 LOS = 0 BIP(B1) = 140 Active Alarms:None LINE AIS = 0 RDI = 2 FEBE = 506 BIP(B2) = 1425 Active Alarms:None PATH AIS = 0 RDI = 0 FEBE = 81 BIP(B3) = 68 LOP = 2 NEWPTR = 0 PSE = 0 NSE = 0 Active Alarms:None ips COAPS = 4 PSBF = 2 State:PSBF_state = False Rx(K1/K2):00/00 Tx(K1/K2):00/00 S1S0 = 00, C2 = 12 CLOCK RECOVERY RDOOL = 0 State:RDOOL_state = False PATH TRACE BUFFER :STABLE Remote hostname :flip Remote interface:SRP2/0 Remote IP addr :10.0.0.3 Remote Ring id :Outer




SRP2/0/0 - Side B (Inner RX, Outer TX) SECTION LOF = 2 LOS = 2 BIP(B1) = 69 Active Alarms:None LINE AIS = 0 RDI = 4 FEBE = 640 BIP(B2) = 689 Active Alarms:None PATH AIS = 0 RDI = 0 FEBE = 86 BIP(B3) = 78 LOP = 0 NEWPTR = 0 PSE = 0 NSE = 0 Active Alarms:None ips COAPS = 12 PSBF = 0 State:PSBF_state = False Rx(K1/K2):00/00 Tx(K1/K2):00/00 S1S0 = 00, C2 = 12 CLOCK RECOVERY RDOOL = 0 State:RDOOL_state = False PATH TRACE BUFFER :STABLE Remote hostname :flop Remote interface:SRP2/0 Remote IP addr :192.168.0.2 Remote Ring id :Inner




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Note The DPTIP interface type and controller type are srp.

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Use the show interfaces srp command to show statistics for the DPTIP interfaces, as shown in the following example:

Router# show interfaces srp 2/0/0 SRP2/0/0 is up, line protocol is up Hardware is SRP over SONET, address is 0000.0000.0001 (bia 0010.f60e.87ff) Internet address is 192.168.0.1/8 MTU 9000 bytes, BW 625000 Kbit, DLY 100 usec, rely 255/255, load 1/255 Encapsulation SRP, loopback not set Last input 00:00:23, output 00:00:03, output hang never Last clearing of "show interface" counters 00:18:35 Queueing strategy:fifo Output queue 0/40, 0 drops; input queue 0/75, 0 drops 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 22 packets input, 2064 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 621 input errors, 621 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 64 packets output, 6452 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out




Use the show srp ips command to show IPS information for a specific interface. The following example shows the MAC addresses of the two nodes that are connected to the interface, and information about the state of the connections:

router# show srp ips 2/0/0




IPS Information for Interface SRP2/0/0 MAC Addresses Side A (Outer ring RX) neighbour 0000.0000.0002 Side B (Inner ring RX) neighbour 0000.0000.0001 Node MAC address 0000.0000.0003 IPS State Side A not wrapped Side B wrapped Side A (Inner ring TX) IPS pkt. sent every 10 sec. (next pkt. after 6 sec.) Side B (Outer ring TX) IPS pkt. sent every 10 sec. (next pkt. after 6 sec.) IPS WTR period is 60 sec. (timer is inactive) Node IPS State WRAPPED IPS Self Detected Requests Side A IDLE Side B SF IPS messages received Side A (Outer ring RX) {0000.0000.0002,SF ,L,1024} Side B (Inner ring RX) {0000.0000.0001,IDLE,S,1024} IPS messages transmitted Side A (Inner ring TX) {0000.0000.0003,SF ,L,1024} Side B (Outer ring TX) {0000.0000.0003,SF ,S,1024}




Topology pkt. sent every 20 sec. (next pkt. after 1 sec.) Last received topology pkt. 00:00:18 Nodes on the ring:2 Hops (outer ring) Address 0 0000.0000.0003 Wrapped 1 0000.0000.0002 Wrapped

Use the show srp topology command to show the identity of the nodes on the DPT ring according to their MAC addresses. The following examples show a three-node DPT ring. In the second example, nodes 1 and 3 are wrapped:

Router# show srp topology Topology Map for Interface SRP2/0/0 Topology pkt. sent every 61 sec. (next pkt. after 16 sec.) Last received topology pkt. 00:00:45 Nodes on the ring:3 Hops (outer ring) Address 0 0000.0000.0001 1 0000.0000.0002 2 0000.0000.0003




Router# show srp topology




Topology Map for Interface SRP2/0/0 Topology pkt. sent every 61 sec. (next pkt. after 54 sec.) Last received topology pkt. 00:00:07 Nodes on the ring:3 Hops (Outer ring) Address 0 0000.0000.0001 Wrapped 1 0000.0000.0002 2 0000.0000.0003 Wrapped




Use the show srp source-counters command to show the number of packets received or rejected when SRP count and reject have been configured. The following example shows 1201 packets have come from another node, and none have been rejected:

Router# show srp source-counters Source Address Information for Interface SRP2/0/0 000a.1234.5678, pkt. count 1201 000b.1234.5678, reject

Creating a DPT Ring

A DPT ring may contain as many as 32 nodes, or as few as 2 nodes. This section documents the layout and configuration of a three-node DPT ring. It is assumed that the actual physical installation of the Cisco 7500 series routers has already been accomplished.

Before the DPT ring can be created, each Cisco 7500 series router (node) must have a DPTIP installed and configured. See Chapter 3, "Removing and Installing Interface Processors," and the "Configuring the DPTIP Interface" section. Once the individual nodes are configured, the inner and outer rings of the DPT ring must be connected as shown in Figure 4-1, and the DPTIPs must be enabled. The procedure below describes the internodal connections of the DPT ring and the configuration commands used to create the ring.

Figure 4-1 Three-Node DPT Ring

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Step 1 While in config mode, use the shutdown command to disable the DPTIP on each node, as shown below:

Router(config)# interface srp 1/0/0 Router(config-if)# shutdown




Step 2 Connect the nodes as shown in Figure 4-2, being careful to observe the receive (RX) and transmit (TX) cable relationship. Table 4-4 lists the internodal cable connections for a three-node DPT ring.

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Note Side A (RX outer/TX inner) of the DPTIP must be connected to side B (TX outer/RX inner) of the DPTIP in the next node in the ring. See Figure 4-2 for the correct orientation of side A and side B.

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Figure 4-2 Internodal Connections of a Three-Node DPT Ring

Step 3 Use the no shutdown command to enable the DPTIP of each node, as shown below:

Router(config)# interface srp 1/0/0 Router(config-if)# no shutdown




Step 4 Use the show srp topology command to verify that all three nodes are recognized as part of the DPT ring. The output shows the number of nodes on the ring and their MAC addresses. See the "Using show Commands to Check System Status" section.

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Table 4-5 Three-Node DPT Ring Cable Connections

Internodal Cable Connections
From Node/Connector	To Node/Connector
Node A/RX outer	Node C/TX outer
Node A/TX inner	Node C/RX inner
Node A/TX outer	Node B/RX outer
Node A/RX inner	Node B/TX inner
Node B/RX outer	Node A/TX outer
Node B/TX inner	Node A/RX inner
Node B/TX outer	Node C/RX outer
Node B/RX inner	Node C/TX inner
Node C/RX outer	Node B/TX outer
Node C/TX inner	Node B/RX inner
Node C/TX outer	Node A/RX outer
Node C/RX inner	Node A/TX inner

Adding or Removing Nodes in a DPT Ring

The following sections describe the procedures for adding or removing a node in a DPT ring:

• Adding a Node to a DPT Ring

• Removing a Node from a DPT Ring

Adding a Node to a DPT Ring

When a new node is to be installed in a DPT ring, a DPTIP is first installed and configured in the Cisco 7500 series router, and the router is then installed and configured as a node in the DPT ring. This section describes the procedure for adding a node to a DPT ring.

To add a node to a DPT ring, you must first reroute the traffic flow over the ring through an alternate path, by creating a ring wrap where the new node is to be installed. Figure 4-3 shows a four-node DPT ring. Use the following procedure to add a node between nodes A and D on the ring:

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Step 1 While in global configuration mode, stop data traffic between nodes A and D on the DPT ring by entering the forced-switch command srp ips request forced-switch a on the node A router. See the "Configuring the Intelligent Protection Switch Feature" section. This creates two ring wraps between the two nodes. (See Figure 4-4.)

Figure 4-3 DPT Ring Topology with Four Nodes

Figure 4-4 DPT Ring with Ring Wraps Created by a Forced Switch

Step 2 From the config mode, enter the command show srp topology to verify that the ring wraps are in place. See the "Using show Commands to Check System Status" section.

Step 3 Disconnect the fiber-optic cables connecting side A of node A to side B of node D. (See Figure 4-4).

Step 4 Connect side A of node A to side B of the new node (node E), using two simplex or one duplex fiber-optic cable. See the "Cables, Connectors, and Pinouts" section on page 1-7. Connect side A of the new node to side B of node D. (See Figure 4-5).

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Note Be careful to observe the proper cable orientation. When using duplex cables, you must reverse one of the cable ends for correct orientation.

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Step 5 If the DPTIP in the new router (node E) has not been configured, do so at this time. See the "Configuring the DPTIP Interface" section.

Step 6 Enter the no shutdown command to bring up the node E router.

Step 7 Confirm that the system recognizes the new node by entering the show srp topology command. The output shows the number of nodes on the ring, their MAC addresses, and the state of the nodes (wrapped or not).

Step 8 Remove the two ring wraps created by the forced switch on nodes A and D by entering the no srp ips request forced-switch a command on the node A router.

Step 9 Confirm that the ring wraps are no longer in place by entering the show srp topology command. The output shows the number of nodes on the ring, their MAC addresses, and the state of the nodes (wrapped or not).

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Figure 4-5 DPT Ring Topology with an Added Node

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Note You can add a node to a DPT ring without entering the srp ips request forced-switch command, but you then cannot control when the traffic is rerouted and restored; the system determines the time instead.

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Removing a Node from a DPT Ring

This section describes the procedure for removing a node from a DPT ring. The following steps describe how to remove node D from a four-node DPT ring, similar to that shown in Figure 4-3.

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Step 1 Isolate node D by entering the forced-switch command srp ips request forced-switch a on the node A router, and srp ips request forced-switch b on the node C router.

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.

Step 3 Disconnect both ends of the cable connecting side A of node D to side B 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.

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This completes the procedure for removing a node from a DPT ring.

Checking the Configuration

After configuring the new interface, use the show commands to display the status of the new interface or all interfaces, and use the ping and loopback commands to check connectivity. This section includes the following subsections:

• Using show Commands to Verify the New Interface Status

• Using the ping Command to Verify Network Connectivity

Using show Commands to Verify the New Interface Status

Table 4-6 demonstrates how you can use the show commands to verify that new interfaces are configured and operating correctly and that the DPTIP appears in them correctly. Sample displays of the output of selected show commands appear in the sections that follow. For complete command descriptions and examples, refer to the publications listed in the "Related Documentation" section on page vi.

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Note The outputs that appear in this document may not match the output you receive when running these commands. The outputs in this document are examples only.

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Table 4-6 Using show Commands 

Command	Function	Example
show version or show hardware	Displays system hardware configuration, the number of each interface type installed, Cisco IOS software version, names and sources of configuration files, and boot images	Router# show version
show controllers	Displays all the current interface processors and their interfaces	Router# show controllers
show diag slot	Displays types of port adapters installed in your system and information about a specific port adapter slot, interface processor slot, or chassis slot	Router# show diag 2
show interfaces type port-adapter-slot-number/ interface-port-number	Displays status information about a specific type of interface (for example, srp) in a Cisco 7500 series router	Router# show interfaces srp 1/0/0
show protocols	Displays protocols configured for the entire system and for specific interfaces	Router# show protocols
show running-config	Displays the running configuration file	Router# show running-config
show startup-config	Displays the configuration stored in NVRAM	Router# show startup-config

Using the ping Command to Verify Network Connectivity

Using the ping command, you can verify that an interface port is functioning properly. This section provides a brief description of this command. Refer to the publications listed in the "Related Documentation" section on page vi for detailed command descriptions and examples.

The ping command sends echo request packets out to a remote device at an IP address that you specify. After sending an echo request, the system waits a specified time for the remote device to reply. Each echo reply is displayed as an exclamation point (!) on the console terminal; each request that is not returned before the specified timeout is displayed as a period (.). A series of exclamation points (!!!!!) indicates a good connection; a series of periods (.....) or the messages [timed out] or [failed] indicate a bad connection.

Following is an example of a successful ping command to a remote server with the address 10.0.0.10:

Router# ping 10.0.0.10 <Return> Type escape sequence to abort. Sending 5, 100-byte ICMP Echoes to 10.0.0.10, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/15/64 ms Router#




If the connection fails, verify that you have the correct IP address for the destination and that the device is active (powered on), and repeat the ping command.

Posted: Wed Aug 25 16:29:58 PDT 2004
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