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Cisco IOS Quality of Service Solutions Command Reference, Release 12.3
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Introduction for the QoS Command Reference, 12.3
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Quality of Service Commands, 12.3: a through f
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Quality of Service Commands, 12.3: ip nbar pdlm through ip rtp priority
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Quality of Service Commands, 12.3: m through n
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Quality of Service Commands, 12.3: o through p
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Quality of Service Commands, 12.3: q through r
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Quality of Service Commands 12.3: send qdm message through show ip nbar pdlm
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Quality of Service Commands, 12.3: show ip nbar port-map through show qdm status
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Quality of Service Commands, 12.3: show queue through vc-hold-queue
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Table Of Contents
ip rsvp admission-control compression predict
ip rsvp authentication challenge
ip rsvp authentication lifetime
ip rsvp authentication window-size
ip rsvp data-packet classification none
ip rsvp dsbm non-resv-send-limit
ip rsvp policy cops report-all
ip rsvp signalling initial-retransmit-delay
ip rsvp signalling patherr state-removal
ip rsvp signalling refresh reduction
ip rsvp signalling refresh reduction ack-delay
ip rtp compression-connections
ip nbar pdlm
To extend or enhance the list of protocols recognized by network-based application recognition (NBAR) through a Cisco-provided Packet Description Language Module (PDLM), use the ip nbar pdlm command in global configuration mode. To unload a PDLM if it was previously loaded, use the no form of this command.
ip nbar pdlm pdlm-name
no ip nbar pdlm pdlm-name
Syntax Description
Defaults
No default behavior or values
Command Modes
Global configuration
Command History
Usage Guidelines
This command is used in global configuration mode to extend the list of protocols recognized by a given version of NBAR or to enhance an existing protocol recognition capability. NBAR can be given an external PDLM at run time. In most cases, the PDLM enables NBAR to recognize new protocols without requiring a new Cisco IOS image or a router reload. Only Cisco can provide you with a new PDLM.
A list of the available PDLMs can be viewed online at Cisco.com.
Examples
The following example configures NBAR to load the citrix.pdlm PDLM from Flash memory on the router:
ip nbar pdlm flash://citrix.pdlmRelated Commands
ip nbar port-map
To configure network-based application recognition (NBAR) to search for a protocol or protocol name using a port number other than the well-known port, use the ip nbar port-map command in global configuration mode. To look for the protocol name using only the well-known port number, use the no form of this command.
ip nbar port-map protocol-name [tcp | udp] port-number
no ip nbar port-map protocol-name [tcp | udp] port-number
Syntax Description
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
This command is used in global configuration mode to tell NBAR to look for the protocol or protocol name, using a port number or numbers other than the well-known Internet Assigned Numbers Authority (IANA)-assigned) port number. For example, use this command to configure NBAR to look for Telnet on a port other than 23. Up to 16 ports can be specified with this command. Port number values can range from 0 to 65535.
Examples
The following example configures NBAR to look for the protocol Structured Query Language (SQL)*NET on port numbers 63000 and 63001 instead of on the well-known port number:
ip nbar port-map sqlnet tcp 63000 63001Related Commands
show ip nbar port-map
Displays the current protocol-to-port mappings in use by NBAR.
ip nbar protocol-discovery
To configure networked-based application recognition (NBAR) to discover traffic for all protocols known to NBAR on a particular interface, use the ip nbar protocol-discovery command in interface configuration mode. To disable traffic discovery, use the no form of this command.
ip nbar protocol-discovery
no ip nbar protocol-discovery
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ip nbar protocol-discovery command to configure NBAR to keep traffic statistics for all protocols known to NBAR. Protocol discovery provides an easy way to discover application protocols transiting an interface so that QoS policies can be developed and applied. The Protocol Discovery feature discovers any protocol traffic supported by NBAR. Protocol discovery can be used to monitor both input and output traffic and may be applied with or without a service policy enabled.
Examples
The following example configures protocol discovery on an Ethernet interface:
interface ethernet 1/3ip nbar protocol-discoveryRelated Commands
show ip nbar protocol-discovery
Displays the statistics gathered by the NBAR Protocol Discovery feature.
ip rsvp admission-control compression predict
To configure Resource Reservation Protocol (RSVP) admission control compression prediction, use the ip rsvp admission-control compression predict command in interface configuration mode. To disable compression prediction, use the no form of this command.
ip rsvp admission-control compression predict [method {rtp | udp} [bytes-saved N]]
no ip rsvp admission-control compression predict [method {rtp | udp} [bytes-saved N]]
Syntax Description
Defaults
This command is enabled by default. The default value of bytes saved for RTP is 36; for UDP, 20.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ip rsvp admission-control compression predict command to disable or enable the RSVP prediction of compression for a specified method or all methods if neither rtp nor udp is selected. You can adjust the default compressibility parameter that RSVP uses to compute the compression factor for each flow.
If you use the ip rsvp admission-control compression predict command to change the compression method or the number of bytes saved per packet, these values affect only new flows, not existing ones.
There are two approaches to compression—conservative and aggressive. When you predict compression conservatively, you assume savings of fewer bytes per packet, but receive a higher likelihood of guaranteed quality of service (QoS). You are allowed more bandwidth per call, but each link accommodates fewer calls. When you predict compression aggressively, you assume savings of more bytes per packet, but receive a lower likelihood of guaranteed QoS. You are allowed less bandwidth per call, but each link accommodates more calls.
Examples
The following command sets the compressibility parameter for flows using the RTP method to 30 bytes saved per packet:
Router(config-if)# ip rsvp admission-control compression predict method rtp bytes-saved 30The following command sets the compressibility parameter for flows using the UDP method to 20 bytes saved per packet:
Router(config-if)# ip rsvp admission-control compression predict method udp bytes-saved 20The following command disables RTP header compression prediction:
Router(config-if)# no ip rsvp admission-control compression predict method rtpThe following command disables UDP header compression prediction:
Router(config-if)# no ip rsvp admission-control compression predict method udp
Note
Disabling the compressibility parameter affects only those flows using the specified method.
Related Commands
show ip rtp header-compression
Displays statistics about RTP header compression.
ip rsvp atm-peak-rate-limit
To set a limit on the peak cell rate (PCR) of reservations for all newly created Resource Reservation Protocol (RSVP) switched virtual circuits (SVCs) established on the current interface or any of its subinterfaces, use the ip rsvp atm-peak-rate-limit command in interface configuration mode. To remove the current peak rate limit, in which case the reservation peak rate is limited by the line rate, use the no form of this command.
ip rsvp atm-peak-rate-limit limit
no ip rsvp atm-peak-rate-limit
Syntax Description
limit
The peak rate limit of the reservation specified, in KB. The minimum value allowed is 1 KB; the maximum value allowed is 2 GB.
Defaults
The peak rate of a reservation defaults to the line rate.
Command Modes
Interface configuration
Command History
Usage Guidelines
Each RSVP reservation corresponds to an ATM SVC with a certain peak cell rate (PCR), sustainable cell rate (SCR), and maximum burst size. The PCR, also referred to as the peak rate, can be configured by the user or allowed to default to the line rate.
RSVP controlled-load reservations do not define any peak rate for the data. By convention, the allowable peak rate in such reservations is taken to be infinity, which is usually represented by a very large number. Under these circumstances, when a controlled-load reservation is converted to an ATM SVC, the peak cell rate for the SVC becomes correspondingly large and may be out of range for the switch. You can use the ip rsvp atm-peak-rate-limit command to limit the peak rate.
The following conditions determine the peak rate limit on the RSVP SVC:
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Note
The peak rate limit is local to the router; it does not affect the normal messaging of RSVP. Only the SVC setup is affected. Large peak rates are sent to the next host without modification.
For RSVP SVCs established on subinterfaces, the peak rate limit applied to the subinterface takes effect on all SVCs created on that subinterface. If a peak rate limit is applied to the main interface, the rate limit has no effect on SVCs created on a subinterface of the main interface even if the limit value on the main interface is lower than the limit applied to the subinterface.
For a given interface or subinterface, a peak rate limit applied to that interface affects only new SVCs created on the interface, not existing SVCs.
Note
Use the show ip rsvp atm-peak-rate-limit command to determine the peak rate limit set for an interface or subinterface, if one is configured.
Examples
The following example sets the peak rate limit (PCR limit) for interface atm2/0/0.1 to 100 KB:
interface atm2/0/0.1ip rsvp atm-peak-rate-limit 100Related Commands
ip rsvp authentication
To activate Resource Reservation Protocol (RSVP) cryptographic authentication, use the ip rsvp authentication command in interface configuration mode. To deactivate authentication, use the no form of this command.
ip rsvp authentication
no ip rsvp authentication
Syntax Description
This command has no arguments or keywords.
Defaults
This command is disabled by default.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ip rsvp authentication command to deactivate and then reactivate RSVP authentication without reentering the other RSVP authentication configuration commands. You should not enable authentication unless you have previously configured a key. If you issue this command before the ip rsvp authentication key command, you get a warning message indicating that RSVP discards all messages until you specify a key. The no ip rsvp authentication command disables RSVP cryptographic authentication. However, the command does not automatically remove any other authentication parameters that you have configured. You must issue a specific no ip rsvp authentication command; for example, no ip rsvp authentication key, no ip rsvp authentication type, or no ip rsvp authentication window-size, if you want to remove them from the configuration.
The ip rsvp authentication command is similar to the ip rsvp neighbor command. However, the ip rsvp authentication command provides better authentication and performs system logging.
Examples
The following command activates authentication on an interface:
Router(config-if)# ip rsvp authenticationThe following command deactivates authentication on an interface:
Router(config-if)# no ip rsvp authenticationRelated Commands
ip rsvp authentication challenge
To make Resource Reservation Protocol (RSVP) perform a challenge-response handshake with any new RSVP neighbors on a network, use the ip rsvp authentication challenge command in interface configuration mode. To disable the challenge-response handshake, use the no form of this command.
ip rsvp authentication challenge
no ip rsvp authentication challenge
Syntax Description
This command has no arguments or keywords.
Defaults
This command is disabled by default.
Command Modes
Interface configuration
Command History
Usage Guidelines
The ip rsvp authentication challenge command requires RSVP to perform a challenge-response handshake with any new RSVP neighbors that are discovered on a network. Such a handshake allows the router to thwart RSVP message replay attacks while booting, especially if there is a long period of inactivity from trusted RSVP neighbors following the reboot. If messages from trusted RSVP neighbors arrive very quickly after the router reboots, then challenges may not be required because the router will have reestablished its security associations with the trusted nodes before the untrusted nodes can attempt replay attacks.
If you enable RSVP authentication challenges, you should consider enabling RSVP refresh reduction by using the ip rsvp signalling refresh reduction command. While a challenge handshake is in progress, the receiving router initiating the handshake discards all RSVP messages from the node being challenged until the handshake-initiating router receives a valid challenge response.
Note
Activating refresh reduction enables the challenged node to resend dropped messages more quickly once the handshake has completed. This causes RSVP to reestablish reservation state faster when the router reboots.
Enable authentication challenges wherever possible to reduce the router's vulnerability to replay attacks.
Examples
The following command shows how to enable RSVP to perform a challenge-response handshake:
Router(config-if)# ip rsvp authentication challengeRelated Commands
ip rsvp authentication key
To specify the key (string) for the Resource Reservation Protocol (RSVP) authentication algorithm, use the ip rsvp authentication key command in interface configuration mode. To disable the key, use the no form of this command.
ip rsvp authentication key passphrase
no ip rsvp authentication key
Syntax Description
passphrase
Phrase that ranges from 8 to 40 characters. See "Usage Guidelines" for additional information.
Defaults
No key is specified.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ip rsvp authentication key command to select the key for the authentication algorithm. This key is a passphrase of 8 to 40 characters. It can include spaces; quotes are not required if spaces are used. The key can consist of more than one word. We recommend that you make the passphrase as long as possible. This key must be the same for all RSVP neighbors on this interface. As with all passwords, you should choose them carefully so that attackers cannot easily guess them.
Here are some guidelines:
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By default, RSVP authentication keys are stored in clear text in the router configuration file, but they can optionally be stored as encrypted text in the configuration file. To enable key encryption, use the global configuration key config-key 1 string command. After you enter this command, the passphrase parameter of each ip rsvp authentication key command is encrypted with the Data Encryption Standard (DES) algorithm when you save the configuration file. If you later issue a no key config-key 1 string command, the RSVP authentication key is stored in clear text again when you save the configuration.
The string argument is not stored in the configuration file; it is stored only in the router's private NVRAM and will not appear in the output of a show run or show config command. Therefore, if you copy the configuration file to another router, any encrypted RSVP keys in that file will not be successfully decrypted by RSVP when the router boots and RSVP authentication will not operate correctly. To recover from this, follow these steps on the new router:
1.
2.
3.
4.
Examples
The following command sets the passphrase to 11223344 in clear text:
Router(config-if)# ip rsvp authentication key 11223344To encrypt the authentication key, issue the key config-key 1 string command as follows:
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# key config-key 1 11223344Router(config)# endRelated Commands
ip rsvp authentication lifetime
To control how long Resource Reservation Protocol (RSVP) maintains security associations with other trusted RSVP neighbors, use the ip rsvp authentication lifetime command in interface configuration mode. To disable the lifetime setting, use the no form of this command.
ip rsvp authentication lifetime hh:mm:ss
no ip rsvp authentication lifetime hh:mm:ss
Syntax Description
hh:mm:ss
Hours: minutes: seconds that RSVP maintains security associations with other trusted RSVP neighbors. The range is 1 second to 24 hours. The default is 30 minutes.
Defaults
Default security association is 30 minutes; range is 1 second to 24 hours.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ip rsvp authentication lifetime command to indicate when to end security associations with RSVP trusted neighbors. If an association's lifetime expires, but at least one valid, RSVP authenticated message was received in that time period, RSVP resets the security association's lifetime to this configured value. When a neighbor stops sending RSVP signaling messages (that is, the last reservation has been torn down), the memory used for the security association is freed as well as when the association's lifetime period ends. The association can be re-created if that RSVP neighbor resumes its signaling. Setting the lifetime to shorter periods allows memory to be recovered faster when the router is handling a lot of short-lived reservations. Setting the lifetime to longer periods reduces the workload on the router when establishing new authenticated reservations.
Use the clear ip rsvp authentication command to free security associations before their lifetimes expire.
Examples
The following command sets the lifetime period for 30 minutes and 5 seconds:
Router(config-if)# ip rsvp authentication lifetime 00:30:05Related Commands
clear ip rsvp authentication
Eliminates RSVP security associations before their lifetimes expire.
ip rsvp authentication type
To specify the algorithm used to generate cryptographic signatures in Resource Reservation Protocol (RSVP) messages, use the ip rsvp authentication type command in interface configuration mode. To disable the type (or to use the default type, md5), use the no form of this command.
ip rsvp authentication type {md5 | sha-1}
no ip rsvp authentication type
Syntax Description
md5
RSA Message Digest 5 algorithm.
sha-1
National Institute of Standards and Technologies (NIST) Secure Hash Algorithm-1; it is newer and more secure than MD5.
Defaults
The default type is md5.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ip rsvp authentication type command to specify the algorithm used to generate cryptographic signatures in RSVP messages. If you do not specify an algorithm, md5 is used.
Examples
The following command sets the type to sha-1:
Router(config-if)# ip rsvp authentication type sha-1Related Commands
ip rsvp authentication window-size
To specify the maximum number of Resource Reservation Protocol (RSVP) authenticated messages that can be received out of order, use the ip rsvp authentication window-size command in interface configuration mode. To disable the window size (or to use the default value of 1), use the no form of this command.
ip rsvp authentication window-size [n]
no ip rsvp authentication window-size
Syntax Description
n
(Optional) Maximum number of authenticated messages that can be received out of order. The range is 1 to 64.
Defaults
The default value is 1.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ip rsvp authentication window-size command to specify the maximum number of authenticated messages that can be received out of order. All RSVP authenticated messages include a sequence number that is used to prevent replays of RSVP messages.
With a default window size of one message, RSVP rejects any duplicate authenticated messages because they are assumed to be replay attacks. However, sometimes bursts of RSVP messages become reordered between RSVP neighbors. If this occurs on a regular basis, and you can verify that the node sending the burst of messages is trusted, you can use the window-size option to allow for the burst size such that RSVP will not discard such reordered bursts. RSVP will still check for duplicate messages within these bursts.
Examples
The following command sets the window size to 2:
Router(config-if)# ip rsvp authentication window-size 2Related Commands
ip rsvp bandwidth
To enable Resource Reservation Protocol (RSVP) for IP on an interface, use the ip rsvp bandwidth command in interface configuration mode. To disable RSVP completely, use the no form of this command. To eliminate only the subpool portion of the bandwidth, use the no form of this command with the keyword sub-pool.
ip rsvp bandwidth [interface-kbps] [single-flow-kbps] [sub-pool kbps]
no ip rsvp bandwidth [interface-kbps] [single-flow-kbps] [sub-pool kbps]
Syntax Description
Defaults
RSVP is disabled by default.
If the ip rsvp bandwidth command is entered but no bandwidth values are supplied (for example, ip rsvp bandwidth is entered followed by pressing the Enter key), a default bandwidth value (that is, 75% of the link bandwidth) is assumed for both the interface-kbps and single-flow-kbps arguments.
Command Modes
Interface configuration
Command History
Usage Guidelines
RSVP cannot be configured with distributed Cisco Express Forwarding (dCEF).
RSVP is disabled by default to allow backward compatibility with systems that do not implement RSVP.
Weighted Random Early Detection (WRED) or fair queueing must be enabled first.
Examples
The following example shows a T1 (1536 kbps) link configured to permit RSVP reservation of up to 1158 kbps, but no more than 100 kbps for any given flow on serial interface 0. Fair queueing is configured with 15 reservable queues to support those reserved flows, should they be required.
Router(config)# interface serial 0Router(config-if)# fair-queue 64 256 15Router(config-if)# ip rsvp bandwidth 1158 100Related Commands
ip rsvp burst policing
To configure a burst factor within the Resource Reservation Protocol (RSVP) token bucket policer on a per-interface basis, use the ip rsvp burst policing command in interface configuration mode. To return to the default value, enter the no form of this command.
ip rsvp burst policing [factor]
no ip rsvp burst policing
Syntax Description
factor
(Optional) Indicates a burst factor value as a percentage of the requested burst of the receiver.
Defaults
The default value is 200; the minimum value is 100, and the maximum value is 700.
Command Modes
Interface configuration
Command History
Usage Guidelines
You configure the burst police factor per interface, not per flow. The burst factor controls how strictly or loosely the traffic of the sender is policed with respect to burst.
The burst factor applies to all RSVP flows installed on a specific interface. You can configure each interface independently for burst policing.
Examples
Here is an example of the ip rsvp burst policing command with a burst factor of 200:
ip rsvp burst policing 200ip rsvp data-packet classification none
To turn off (disable) Resource Reservation Protocol (RSVP) data packet classification, use the ip rsvp data-packet classification none command in interface configuration mode. To turn on (enable) data-packet classification, use the no form of this command.
ip rsvp data-packet classification none
no ip rsvp data-packet classification
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ip rsvp data-packet classification none command when you do not want RSVP to process every packet. Configuring RSVP so that not every packet is processed eliminates overhead and improves network performance and scalability.
Examples
This section contains two examples of the ip rsvp data-packet classification none command. In the first example, data packet classification is turned off (disabled), as follows:
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# int atm6/0Router(config-if)# ip rsvp data-packet classification noneIn the second example, data packet classification is turned on (enabled), as follows:
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# int atm6/0Router(config-if)# no ip rsvp data-packet classificationRelated Commands
ip rsvp dsbm candidate
To configure an interface as a Designated Subnetwork Bandwidth Manager (DSBM) candidate, use the ip rsvp dsbm candidate command in interface configuration mode. To disable DSBM on an interface, which exempts the interface as a DSBM candidate, use the no form of this command.
ip rsvp dsbm candidate [priority]
no ip rsvp dsbm candidate
Syntax Description
priority
(Optional) A value in the range from 64 to 128. Among contenders for the DSBM, the interface with the highest priority number wins the DSBM election process.
Defaults
An interface is not configured as a DSBM contender by default. If you use this command to enable the interface as a DSBM candidate and you do not specify a priority, the default priority of 64 is assumed.
Command Modes
Interface configuration
Command History
12.0(5)T
This command was introduced.
12.1(1)T
This command was integrated into Cisco IOS Release 12.1(1)T.
Usage Guidelines
SBM protocol entities, any one of which can manage resources on a segment, can reside in Layer 2 or Layer 3 devices. Many SBM-capable devices may be attached to a shared Layer 2 segment. When more than one SBM exists on a given segment, one of the SBMs is elected to be the DSBM. The elected DSBM is responsible for exercising admission control over requests for resource reservations on a segment, which, in the process, becomes a managed segment. A managed segment includes those interconnected parts of a shared LAN that are not separated by DSBMs. In all circumstances, only one, if any, DSBM exists for each Layer 2 segment.
You can configure an interface to have a DSBM priority in the range from 64 to 128. You can exempt an interface from participation in the DSBM election on a segment but still allow the system to interact with the DSBM if a DSBM is present on the segment. In other words, you can allow a Resource Reservation Protocol (RSVP)-enabled interface on a router connected to a managed segment to be managed by the DSBM even if you do not configure that interface to participate as a candidate in the DSBM election process. To exempt an interface from DSBM candidacy, do not issue the ip rsvp dsbm candidate command on that interface.
RSVP cannot be configured with VIP-distributed Cisco Express Forwarding (dCEF).
Examples
The following example configures Ethernet interface 2 as a DSBM candidate with a priority of 100:
interface Ethernet2ip rsvp dsbm candidate 100Related Commands
ip rsvp dsbm non-resv-send-limit
To configure the NonResvSendLimit object parameters, use the ip rsvp dsbm non-resv-send-limit command in interface configuration mode. To use the default NonResvSendLimit object parameters, use the no form of this command.
ip rsvp dsbm non-resv-send-limit {rate kbps | burst kilobytes | peak kbps | min-unit bytes | max-unit bytes}
no ip rsvp dsbm non-resv-send-limit {rate kbps | burst kilobytes | peak kbps | min-unit bytes | max-unit bytes}
Syntax Description
Defaults
The default for the rate, burst, peak, min-unit, and max-unit keywords is unlimited; all traffic can be sent without a valid Resource Reservation Protocol (RSVP) reservation.
Command Modes
Interface configuration
Command History
Usage Guidelines
To configure the per-flow limit on the amount of traffic that can be sent without a valid RSVP reservation, configure the rate, burst, peak, min-unit, and max-unit values for finite values greater than 0.
To allow all traffic to be sent without a valid RSVP reservation, configure the rate, burst, peak, min-unit, and max-unit values for unlimited traffic. To configure the parameters for unlimited traffic, you can either omit the command, or enter the no form of the command (for example, no ip rsvp dsbm non-resv-send-limit rate). Unlimited is the default value.
The absence of the NonResvSendLimit object allows any amount of traffic to be sent without a valid RSVP reservation.
RSVP cannot be configured with VIP-distributed Cisco Express Forwarding (dCEF).
Examples
The following example configures Ethernet interface 2 as a DSBM candidate with a priority of 100, an average rate of 500 kBps, a maximum burst size of 1000 KB, a peak rate of 500 kBps, and unlimited minimum and maximum packet sizes:
interface Ethernet2ip rsvp dsbm candidate 100ip rsvp dsbm non-resv-send-limit rate 500ip rsvp dsbm non-resv-send-limit burst 1000ip rsvp dsbm non-resv-send-limit peak 500Related Commands
ip rsvp flow-assist
To enable Resource Reservation Protocol (RSVP) to attach itself to NetFlow so that it can leverage NetFlow services to obtain flow classification information about packets in order to update its token bucket and set IP Precedence as required, use the ip rsvp flow-assist command in interface configuration mode. To detach RSVP from NetFlow, use the no form of this command.
ip rsvp flow-assist
no ip rsvp flow-assist
Syntax Description
This command has no arguments or keywords.
Defaults
This command has no default behavior or values. (RSVP does not use NetFlow as a packet filtering mechanism.)
Command Modes
Interface configuration
Command History
Usage Guidelines
For RSVP to maintain token buckets and set IP Precedence on packets traversing the flow, it must interact with the underlying packet forwarding mechanism in order to obtain the information it needs. RSVP uses NetFlow for this purpose.
If RSVP is used on non-ATM links and RSVP must set IP Precedence without relying on traffic policing, weighted fair queueing (WFQ) cannot be used. In this case, a method of attaching RSVP to the underlying forwarding mechanism is required. The ip rsvp flow-assist command satisfies this requirement. It allows RSVP to attach itself to NetFlow so that it can use NetFlow to obtain information about packets, which it can then use to update its token bucket and set IP Precedence. NetFlow does not police packets or flows. For this reason, when RSVP is configured in this mode, it can only set IP Precedence and not otherwise police traffic.
In summary, you should use this command only when all of the following conditions exist:
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When all of these conditions prevail, RSVP is completely detached from the data flow path and, thus, has no way to detect packets. Use of this command enables RSVP to detect packets so that it can mark them.
RSVP cannot be configured with VIP-distributed Cisco Express Forwarding (dCEF).
Use the show ip rsvp interface command to determine whether this command is in effect for an interface or subinterface.
Examples
The following example enables RSVP on the ATM interface 2/0/0 to attach itself to NetFlow:
interface atm2/0/0ip rsvp flow-assistRelated Commands
ip rsvp layer2 overhead
To control the overhead accounting performed by Resource Reservation Protocol (RSVP)/weighted fair queueing (WFQ) when a flow is admitted onto an ATM permanent virtual circuit (PVC), use the ip rsvp layer2 overhead command in interface configuration mode. To disable the overhead accounting, use the no form of this command.
ip rsvp layer2 overhead [h c n]
no ip rsvp layer2 overhead [h c n]
Syntax Description
