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Cisco IOS Quality of Service Solutions Command Reference, Release 12.1
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About the Cisco IOS Software Documentation
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Using Cisco IOS Software
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Commands: access-list rate-limit -- frame-relay ip rtp priority
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Commands: ip rsvp atm-peak-rate-limit -- ip rtp priority
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Commands: match access-group -- pvc-bundle
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Commands: queue-limit -- set ip precedence
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Commands: show access-lists rate-limit -- traffic-shape rate
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Index
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Table Of Contents
ip rsvp dsbm non-resv-send-limit
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 interface configuration command. 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 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 PCR 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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The peak rate defaults to the line rate.
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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 for interface atm2/0/0.1 to 100 KB:
interface atm2/0/0.1ip rsvp atm-peak-rate-limit 100Related Commands
ip rsvp bandwidth
To enable Resource Reservation Protocol (RSVP) for IP on an interface, use the ip rsvp bandwidth interface configuration command. To disable RSVP, use the no form of this command.
ip rsvp bandwidth [interface-kbps [single-flow-kbps]]
no ip rsvp bandwidth [interface-kbps [single-flow-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 a carriage return, or pressing the Return or Enter key), a default bandwidth value 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 VIP-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.
interface serial 0fair-queue 64 256 15ip rsvp bandwidth 1158 100Related Commands
ip rsvp dsbm candidate
To configure an interface as a Designated Subnetwork Bandwidth Manager (DSBM) candidate, use the ip rsvp dsbm candidate interface configuration command. 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 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
The ip rsvp dsbm-candidate command was introduced.
12.1(1)
This command was introduced, replacing the ip rsvp dsbm-candidate command.
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 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 interface Ethernet2 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 interface configuration command. 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. To configure the parameters for unlimited, you can either omit the command, or enter the no version 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 interface Ethernet2 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 interface configuration command. 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
None (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 atm2/0/0 interface to attach itself to NetFlow:
interface atm2/0/0ip rsvp flow-assistRelated Commands
ip rsvp neighbor
To enable neighbors to request a reservation, use the ip rsvp neighbor interface configuration command. To disable this feature, use the no form of this command.
ip rsvp neighbor access-list-number
no ip rsvp neighbor access-list-number
Syntax Description
access-list-number
Number of a standard or extended access list. It can be any number in the range 1 to 199.
Defaults
The router accepts messages from any neighbor.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command to allow only specific Resource Reservation Protocol (RSVP) neighbors to make a reservation. If no limits are specified, any neighbor can request a reservation. If an access list is specified, only neighbors meeting the specified access list requirements can make a reservation.
RSVP cannot be configured with VIP-Distributed Cisco Express Forwarding (dCEF).
Examples
The following example allows neighbors meeting access list 1 requirements to request a reservation:
interface ethernet 0ip rsvp neighbor 1Related Commands
ip rsvp precedence
To enable the router to mark the IP Precedence value of the type of service (ToS) byte for packets in a Resource Reservation Protocol (RSVP) reserved path using the specified values for packets that either conform to or exceed the RSVP flowspec, use the ip rsvp precedence interface configuration command. To remove existing IP Precedence settings, use the no form of this command; if neither conform nor exceed is specified, all IP Precedence settings are removed.
ip rsvp precedence {[conform precedence-value] [exceed precedence-value]}
no ip rsvp precedence [conform] [exceed]
Syntax Description
Defaults
The IP Precedence bits of the ToS byte are left unmodified when this command is not used. The default state is equivalent to execution of the no ip rsvp precedence command.
Command Modes
Interface configuration
Command History
Usage Guidelines
Packets in an RSVP reserved path are divided into two classes: those that conform to the reservation flowspec and those that correspond to a reservation but that exceed, or are outside, the reservation flowspec.
The ip rsvp precedence command allows you to set the IP Precedence values to be applied to packets belonging to these two classes. You must specify the IP Precedence value for at least one class of traffic when you use this command. You can use a single instance of the command to specify values for both classes, in which case you can specify the conform and exceed keywords in either order.
As part of its input processing, RSVP uses the ip rsvp precedence command to set the IP Precedence bits on conforming and nonconforming packets. If per-VC DWRED is configured, the system uses the IP Precedence and ToS bit settings on the output interface in its packet drop process. The IP Precedence setting of a packet can also be used by interfaces on downstream routers.
Execution of the ip rsvp precedence command causes IP Precedence values for all preexisting reservations on the interface to be modified.
Note
RSVP receives packets from the underlying forwarding mechanism. Therefore, before you use the ip rsvp precedence command to set IP Precedence, one of the following features is required:
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Note
Examples
The following example sets the IP Precedence value to 3 for all traffic on the atm0 interface that conforms to the RSVP flowspec and to 2 for all traffic that exceeds the flowspec:
interface atm0ip rsvp precedence conform 3 exceed 2The following example sets the IP Precedence value to 2 for all traffic on the ATM1 interface that conforms to the RSVP flowspec. The IP Precedence values of those packets that exceed the flowspec are not altered in any way.
interface ATM1ip rsvp precedence conform 2Related Commands
ip rsvp reservation
To enable a router to simulate receiving and forwarding Resource Reservation Protocol (RSVP) RESV messages, use the ip rsvp reservation global configuration command. To disable this feature, use the no form of this command.
ip rsvp reservation session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-dport sender-sport next-hop-ip-address next-hop-interface {ff | se | wf} {rate | load} bandwidth burst-size
no ip rsvp reservation session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-dport sender-sport next-hop-ip-address next-hop-interface {ff | se | wf} {rate | load} bandwidth burst-size
Syntax Description
Defaults
The router does not simulate receiving and processing RSVP RESV messages by default.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to make the router simulate receiving RSVP RESV messages from a downstream host. This command can be used to proxy RSVP RESV messages for non-RSVP-capable receivers. By giving a local (loopback) next hop address and next hop interface, you can also use this command to proxy RSVP for the router you are configuring.
Note
Examples
The following example specifies the use of a Shared Explicit style of reservation and the controlled load service, with token buckets of 100 or 150 kbps and 60 or 65 kbps maximum queue depth:
ip rsvp reservation 224.250.0.2 172.16.1.1 UDP 20 30 172.16.4.1 Et1 se load 100 60ip rsvp reservation 224.250.0.2 172.16.2.1 TCP 20 30 172.16.4.1 Et1 se load 150 65The following example specifies the use of a Wild Card Filter style of reservation and the guaranteed bit rate service, with token buckets of 300 or 350 kbps and 60 or 65 kbps maximum queue depth:
ip rsvp reservation 224.250.0.3 0.0.0.0 UDP 20 0 172.16.4.1 Et1 wf rate 300 60ip rsvp reservation 226.0.0.1 0.0.0.0 UDP 20 0 172.16.4.1 Et1 wf rate 350 65Note that the Wild Card Filter does not admit the specification of the sender; it accepts all senders. This action is denoted by setting the source address and port to zero. If, in any filter style, the destination port is specified to be zero, RSVP does not permit the source port to be anything else; it understands that such protocols do not use ports or that the specification applies to all ports.
Related Commands
ip rsvp reservation-host
To enable a router to simulate a host generating Resource Reservation Protocol (RSVP) RESV messages, use the ip rsvp reservation-host global configuration command. To disable this feature, use the no form of this command.
ip rsvp reservation-host session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-dport sender-sport {ff | se | wf} {rate | load} bandwidth burst-size
no ip rsvp reservation-host session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-dport sender-sport {ff | se | wf} {rate | load} bandwidth burst-size
Syntax Description
Defaults
The router does not simulate a host generating RSVP RESV messages by default.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to make the router simulate a host generating its own RSVP RESV messages. This command is similar to the ip rsvp reservation command, which can cause the router to generate RESV messages on behalf of another host.
The main differences between the ip rsvp reservation-host and ip rsvp reservation commands follow:
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Because you cannot use the command to proxy RSVP for non-RSVP-capable hosts or for multicast sessions, the ip rsvp reservation-host command is used mostly for debugging and testing purposes.
RSVP cannot be configured with VIP-Distributed Cisco Express Forwarding (dCEF).
Examples
The following example specifies the use of a Shared Explicit style of reservation and the controlled load service, with token buckets of 100 or 150 kbps and 60 or 65 kbps maximum queue depth:
ip rsvp reservation-host 10.1.1.1 10.30.1.4 UDP 20 30 se load 100 60ip rsvp reservation-host 10.40.2.2 10.22.1.1 TCP 20 30 se load 150 65Related Commands
ip rsvp sender
To enable a router to simulate receiving and forwarding Resource Reservation Protocol (RSVP) PATH messages, use the ip rsvp sender global configuration command. To disable this feature, use the no form of this command.
ip rsvp sender session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-dport sender-sport previous-hop-ip-address previous-hop-interface bandwidth burst-size
no ip rsvp sender session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-dport sender-sport previous-hop-ip-address previous-hop-interface bandwidth burst-size
Syntax Description
Defaults
The router does not simulate receiving and processing RSVP PATH messages by default.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to make the router simulate that it is receiving RSVP PATH messages from an upstream host. The command can be used to proxy RSVP PATH messages for non-RSVP-capable senders. By including a local (loopback) previous hop address and previous hop interface, you can also use this command to proxy RSVP for the router you are configuring.
RSVP cannot be configured with VIP-Distributed Cisco Express Forwarding (dCEF).
Examples
The following example sets up the router to act like it is receiving RSVP PATH messages using UDP over the loopback 1 interface:
ip rsvp sender 224.250.0.1 172.16.2.1 udp 20 30 172.16.2.1 loopback 1 50 5ip rsvp sender 224.250.0.2 172.16.2.1 udp 20 30 172.16.2.1 loopback 1 50 5Related Commands
ip rsvp sender-host
To enable a router to simulate a host generating a Resource Reservation Protocol (RSVP) PATH message, use the ip rsvp sender-host global configuration command. To disable this feature, use the no form of this command.
ip rsvp sender-host session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-dport sender-sport bandwidth burst-size
no ip rsvp sender-host session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-dport sender-sport bandwidth burst-size
Syntax Description
Defaults
The router does not simulate RSVP PATH message generation by default.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to make the router simulate a host generating its own RSVP PATH messages. This command is similar to the ip rsvp sender command, which can cause the router to generate RSVP PATH messages on behalf of another host.
The main differences between the ip rsvp sender-host and ip rsvp sender commands follow:
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Because you cannot use the command to proxy RSVP for non-RSVP-capable hosts, the ip rsvp sender-host command is used mostly for debugging and testing purposes.
RSVP cannot be configured with VIP-Distributed Cisco Express Forwarding (dCEF).
Examples
The following example sets up the router to act like a host that will send traffic to the given multicast address:
ip rsvp sender-host 224.250.0.1 10.24.2.1 udp 20 30 50 5ip rsvp sender-host 227.0.0.1 10.24.2.1 udp 20 30 50 5Related Commands
ip rsvp svc-required
To enable creation of a switched virtual circuit (SVC) to service any new Resource Reservation Protocol (RSVP) reservation made on the interface or subinterface of an Enhanced ATM port adapter (PA-A3), use the ip rsvp svc-required interface configuration command. To disable SVC creation for RSVP reservations, use the no form of this command.
ip rsvp svc-required
no ip rsvp svc-required
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled. This command applies exclusively to the RSVP-ATM QoS Interworking feature.
Command Modes
Interface configuration
Command History
Usage Guidelines
Usually reservations are serviced when RSVP classifies packets and a queueing mechanism schedules them for transmission to manage congestion. Traditionally, RSVP is used with weighted fair queueing (WFQ). When RSVP is coupled with WFQ, all of the packets visible to WFQ are also visible to RSVP, which allows RSVP to identify and take action on packets important to it. In this case, WFQ provides bandwidth guarantees.
However, when the ip rsvp svc-required command is used to configure an interface or subinterface, a new SVC is established and used to service each new reservation on the interface. ATM SVCs are used to provide bandwidth guarantees and NetFlow is used on input interfaces to make data packets visible to RSVP.
Note
This command must be executed on both ends of an SVC driven by RSVP. This command is supported only for the Enhanced ATM port adapter (PA-A3) and its subinterfaces.
Note
Use the show ip rsvp interface command to determine whether this command is in effect for any interface or subinterface.
Examples
The following example signals RSVP that reservations made on the atm2/0/0 interface will be serviced by creation of an SVC:
interface atm2/0/0ip rsvp svc-requiredRelated Commands
ip rsvp tos
To enable the router to mark the five low-order type of service (ToS) bits of the IP header ToS byte for packets in a Resource Reservation Protocol (RSVP) reserved path using the specified values for traffic that either conforms to or exceeds the RSVP flowspec, use the ip rsvp tos interface configuration command. To remove existing settings for the ToS bits, use the no form of this command; if neither conform nor exceed is specified, all settings for the ToS bits are removed.
ip rsvp tos {[conform tos-value] [exceed tos-value]}
no ip rsvp tos [conform] [exceed]
Syntax Description
Defaults
The ToS bits of the ToS byte are left unmodified when this command is not used. (The default behavior is equivalent to use of the no ip rsvp tos command.)
Command Modes
Interface configuration
Command History
Usage Guidelines
Packets in an RSVP reserved path are divided into two classes: those that conform to the reservation flowspec and those that correspond to a reservation but that exceed, or are outside, the reservation flowspec.
The ip rsvp tos command allows you to set the ToS values to be applied to packets belonging to these two classes. You must specify the ToS value for at least one class of traffic when you use this command. You can use a single instance of the command to specify values for both classes, in which case you can specify the conform and exceed keywords in either order.
As part of its input processing, RSVP uses the ip rsvp tos command configuration to set the ToS bits of the ToS byte on conforming and nonconforming packets. If per-virtual circuit (VC) VIP-Distributed Weighted Random Early Detection (DWRED) is configured, it uses the ToS bit and IP Precedence bit settings on the output interface in its packet drop process. The ToS bit and IP Precedence bit settings of a packet can also be used by interfaces on downstream routers.
Execution of the ip rsvp tos command causes ToS bit values for all preexisting reservations on the interface to be modified.
Note
Note
RSVP receives packets from the underlying forwarding mechanism. Therefore, to use the ip rsvp tos command to set the ToS bits, one of the following features is required:
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Note
Examples
The following example sets the ToS bits value to 4 for all traffic on the atm1 interface that conforms to the RSVP flowspec. ToS bits on packets exceeding the flowspec are not altered.
interface atm1ip rsvp tos conform 4Related Commands
ip rsvp udp-multicasts
To instruct the router to generate User Datagram Protocol (UDP)-encapsulated Resource Reservation Protocol (RSVP) multicasts whenever it generates an IP-encapsulated multicast packet, use the ip rsvp udp-multicasts interface configuration command. To disable this feature, use the no form of this command.
ip rsvp udp-multicasts [multicast-address]
no ip rsvp udp-multicasts [multicast-address]
Syntax Description
Defaults
The generation of UDP multicasts is disabled. If a system sends a UDP-encapsulated RSVP message to the router, the router begins using UDP for contact with the neighboring system. The router uses multicast address 224.0.0.14 and starts sending to UDP port 1699. If the command is entered with no specifying multicast address, the router uses the same multicast address.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command to instruct a router to generate UDP-encapsulated RSVP multicasts whenever it generates an IP-encapsulated multicast packet. Some hosts require this trigger from the router.
RSVP cannot be configured with VIP-Distributed Cisco Express Forwarding (dCEF).
Examples
The following example reserves up to 7500 kbps on Ethernet interface 2, with up to 1 Mbps per flow. The router is configured to use UDP encapsulation with the multicast address 224.0.0.14.
interface ethernet 2ip rsvp bandwidth 7500 1000ip rsvp udp-multicasts 224.0.0.14Related Commands
ip rtp priority
To reserve a strict priority queue for a set of Real-Time Transport Protocol (RTP) packet flows belonging to a range of User Datagram Protocol (UDP) destination ports, use the ip rtp priority interface configuration command. To disable the strict priority queue, use the no form of this command.
ip rtp priority starting-rtp-port-number port-number-range bandwidth
no ip rtp priority
Syntax Description
Defaults
This command has no default behavior or values.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command is most useful for voice applications, or other applications that are delay-sensitive.
This command extends and improves on the functionality offered by the ip rtp reserve command by allowing you to specify a range of UDP/RTP ports whose voice traffic is guaranteed strict priority service over any other queues or classes using the same output interface. Strict priority means that if packets exist in the priority queue, they are dequeued and sent first—that is, before packets in other queues are dequeued. We recommend that you use the ip rtp priority command instead of the ip rtp reserve command for voice configurations.
This command can be used in conjunction with either weighted fair queueing (WFQ) or class-based WFQ (CBWFQ) on the same outgoing interface. In either case, traffic matching the range of ports specified for the priority queue is guaranteed strict priority over other CBWFQ classes or WFQ flows; voice packets in the priority queue are always serviced first.
Remember the following when using the ip rtp priority command:
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Remember the following guidelines when configuring the bandwidth parameter:
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For more information on IP RTP Priority bandwidth allocation, refer to the section "IP RTP Priority" in the chapter "Congestion Management Overview" in the Cisco IOS Quality of Service Solutions Configuration Guide.
Examples
The following example first defines a CBWFQ configuration and then reserves a strict priority queue with the following values: a starting RTP port number of 16384, a range of 16383 UDP ports, and a maximum bandwidth of 40 kbps:
! The following commands define a class map:class-map class1match access-group 101exit! The following commands create and attach a policy map:policy-map policy1class class1bandwidth 3000queue-limit 30random-detectrandom-detect precedence 0 32 256 100exitinterface Serial1service-policy output policy1! The following command reserves a strict priority queue:ip rtp priority 16384 16383 40Related Commands
