Prerequisites for RSVP Refresh Reduction and Reliable Messaging
RSVP must be configured on two or more devices within the network before you can use the RSVP Refresh Reduction and Reliable Messaging feature.
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The RSVP Refresh Reduction and Reliable Messaging feature includes refresh reduction, which improves the scalability, latency, and reliability of Resource Reservation Protocol (RSVP) signaling to enhance network performance and message delivery.
Release |
Modification |
---|---|
12.2(13)T |
This feature was introduced. |
12.0(24)S |
This feature was integrated into Cisco IOS Release 12.0(24)S. |
12.2(14)S |
This feature was integrated into Cisco IOS Release 12.2(14)S. |
12.0(26)S |
Two commands, ip rsvp signalling refresh misses and ip rsvp signalling refresh interval , were added into Cisco IOS Release 12.0(26)S. |
12.0(29)S |
The burst and max-size argument defaults for the ip rsvp signalling rate-limit command were increased to 8 messages and 2000 bytes, respectively. |
12.2(28)SB |
This feature was integrated into Cisco IOS Release 12.2(28)SB. |
12.2(18)SXF5 |
This feature was integrated into Cisco IOS Release 12.2(18)SXF5. |
12.2(33)SRB |
This feature was integrated into Cisco IOS Release 12.2(33)SRB. |
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RSVP must be configured on two or more devices within the network before you can use the RSVP Refresh Reduction and Reliable Messaging feature.
Multicast flows are not supported for the reliable messages and summary refresh features.
RSVP is a network-control, soft-state protocol that enables Internet applications to obtain special qualities of service (QoS) for their data flows. As a soft-state protocol, RSVP requires that state be periodically refreshed. If refresh messages are not transmitted during a specified interval, RSVP state automatically times out and is deleted.
In a network that uses RSVP signaling, reliability and latency problems occur when an RSVP message is lost in transmission. A lost RSVP setup message can cause a delayed or failed reservation; a lost RSVP refresh message can cause a delay in the modification of a reservation or in a reservation timeout. Intolerant applications can fail as a result.
Reliability problems can also occur when there is excessive RSVP refresh message traffic caused by a large number of reservations in the network. Using summary refresh messages can improve reliability by significantly reducing the amount of RSVP refresh traffic.
![]() Note |
RSVP packets consist of headers that identify the types of messages, and object fields that contain attributes and properties describing how to interpret and act on the content. |
The RSVP Refresh Reduction and Reliable Messaging feature (see the figure below) includes refresh reduction, which improves the scalability, latency, and reliability of RSVP signaling by introducing the following extensions:
Reliable messages (MESSAGE_ID, MESSAGE_ID_ACK objects, and ACK messages)
Bundle messages (reception and processing only)
Summary refresh messages (MESSAGE_ID_LIST and MESSAGE_ID_NACK objects)
The reliable messages extension supports dependable message delivery among neighboring devices by implementing an acknowledgment mechanism that consists of a MESSAGE_ID object and a MESSAGE_ID_ACK object. The acknowledgments can be transmitted in an ACK message or piggybacked in other RSVP messages.
Each RSVP message contains one MESSAGE_ID object. If the ACK_Desired flag field is set within the MESSAGE_ID object, the receiver transmits a MESSAGE_ID_ACK object to the sender to confirm delivery.
A bundle message consists of several standard RSVP messages that are grouped into a single RSVP message.
A bundle message must contain at least one submessage. A submessage can be any RSVP message type other than another bundle message. Submessage types include Path, PathErr, Resv, ResvTear, ResvErr, ResvConf, and ACK.
Bundle messages are addressed directly to the RSVP neighbor. The bundle header immediately follows the IP header, and there is no intermediate transport header.
When a device receives a bundle message that is not addressed to one of its local IP addresses, it forwards the message.
![]() Note |
Bundle messages can be received, but not sent. |
A summary refresh message supports the refreshing of RSVP state without the transmission of conventional Path and Resv messages. Therefore, the amount of information that must be transmitted and processed to maintain RSVP state synchronization is greatly reduced.
A summary refresh message carries a set of MESSAGE_ID objects that identify the Path and Resv states that should be refreshed. When an RSVP node receives a summary refresh message, the node matches each received MESSAGE_ID object with the locally installed Path or Resv state. If the MESSAGE_ID objects match the local state, the state is updated as if a standard RSVP refresh message were received. However, if a MESSAGE_ID object does not match the receiver’s local state, the receiver notifies the sender of the summary refresh message by transmitting a MESSAGE_ID_NACK object.
When a summary refresh message is used to refresh the state of an RSVP session, the transmission of conventional refresh messages is suppressed. The summary refresh extension cannot be used for a Path or Resv message that contains changes to a previously advertised state. Also, only a state that was previously advertised in Path or Resv messages containing MESSAGE_ID objects can be refreshed by using a summary refresh message.
Refresh reduction reduces the volume of steady-state network traffic generated, the amount of CPU resources used, and the response time, thereby enhancing network performance.
The MESSAGE_ID and the MESSAGE_ID_ACK objects ensure the reliable delivery of messages and support rapid state refresh when a network problem occurs. For example, MESSAGE_ID_ACK objects are used to detect link transmission losses.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
enable Example:
|
Enables privileged EXEC mode.
|
||
Step 2 |
configure terminal Example:
|
Enters global configuration mode. |
||
Step 3 |
interface interface number Example:
|
Configures the interface type and enters interface configuration mode. |
||
Step 4 |
ip rsvp bandwidth [interface-kbps ] [single-flow-kbps ] [sub-pool [sub-pool-kbps ]] Example:
|
Enables RSVP on an interface.
|
||
Step 5 |
end Example:
|
(Optional) Returns to privileged EXEC mode. |
Perform the following task to enable RSVP refresh reduction.
Command or Action | Purpose | |
---|---|---|
Step 1 |
enable Example:
|
Enables privileged EXEC mode.
|
Step 2 |
configure terminal Example:
|
Enters global configuration mode. |
Step 3 |
ip rsvp signalling refresh reduction Example:
|
Enables refresh reduction. |
Step 4 |
end Example:
|
Returns to privileged EXEC mode. |
Perform the following task to verify that the RSVP Refresh Reduction and Reliable Messaging feature is functioning.
Command or Action | Purpose | |
---|---|---|
Step 1 |
enable Example:
|
Enables privileged EXEC mode.
|
Step 2 |
clear ip rsvp counters [confirm ] Example:
|
(Optional) Clears (sets to zero) all IP RSVP counters that are being maintained by the device. |
Step 3 |
show ip rsvp Example:
|
(Optional) Displays RSVP rate-limiting, refresh-reduction, and neighbor information. |
Step 4 |
show ip rsvp counters [ interface interface-unit | summary | neighbor ] Example:
|
(Optional) Displays the number of RSVP messages that were sent and received on each interface.
|
Step 5 |
show ip rsvp interface [ interface-type interface-number ] [ detail ] Example:
|
(Optional) Displays information about interfaces on which RSVP is enabled including the current allocation budget and maximum available bandwidth.
|
Step 6 |
show ip rsvp neighbor [ detail ] Example:
|
(Optional) Displays RSVP-neighbor information including IP addresses.
|
In the following example, RSVP refresh reduction is enabled:
Device# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Device(config)# interface Ethernet1
Device(config-if)# ip rsvp bandwidth 7500 7500
Device(config-if)# exit
Device(config)# ip rsvp signalling refresh reduction
Device(config)# end
The following example verifies that RSVP refresh reduction is enabled:
Device# show running-config
Building configuration...
Current configuration : 1503 bytes
!
version 12.2
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
service internal
!
hostname Device
!
no logging buffered
logging rate-limit console 10 except errors
!
ip subnet-zero
ip cef
!
ip multicast-routing
no ip dhcp-client network-discovery
lcp max-session-starts 0
mpls traffic-eng tunnels
!
!
interface Loopback0
ip address 192.168.1.1 255.255.255.0
ip rsvp bandwidth 1705033 1705033
!
interface Tunnel777
no ip address
shutdown
!
interface Ethernet0
ip address 192.168.0.195 255.0.0.0
no ip mroute-cache
media-type 10BaseT
!
interface Ethernet1
ip address 192.168.5.2 255.255.255.0
no ip redirects
no ip proxy-arp
ip pim dense-mode
no ip mroute-cache
media-type 10BaseT
ip rsvp bandwidth 7500 7500
!
interface Ethernet2
ip address 192.168.1.2 255.255.255.0
no ip redirects
no ip proxy-arp
ip pim dense-mode
no ip mroute-cache
media-type 10BaseT
mpls traffic-eng tunnels
ip rsvp bandwidth 7500 7500
!
interface Ethernet3
ip address 192.168.2.2 255.255.255.0
ip pim dense-mode
media-type 10BaseT
mpls traffic-eng tunnels
!
!
router eigrp 17
network 192.168.0.0
network 192.168.5.0
network 192.168.12.0
network 192.168.30.0
auto-summary
no eigrp log-neighbor-changes
!
ip classless
no ip http server
ip rsvp signalling refresh reduction
!
!
!
!
line con 0
exec-timeout 0 0
line aux 0
line vty 0 4
login
transport input pad v120 telnet rlogin udptn
!
end
The following sections provide references related to the RSVP Refresh Reduction and Reliable Messaging feature.
Related Topic |
Document Title |
---|---|
Cisco IOS commands |
|
RSVP commands: complete command syntax, command mode, defaults, usage guidelines, and examples |
Cisco IOS Quality of Service Solutions Command Reference |
QoS features including signaling, classification, and congestion management |
"Quality of Service Overview" module |
Standard |
Title |
---|---|
None |
-- |
MIB |
MIBs Link |
---|---|
No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFC |
Title |
---|---|
RFC 2205 |
Resource Reservation Protocol |
RFC 2206 |
RSVP Management Information Base Using SMIv2 |
RFC 2209 |
RSVP--Version 1 Message Processing Rules |
RFC 2210 |
The Use of RSVP with IETF Integrated Services |
RFC 2211/2212 |
Specification of the Controlled-Load Network Element Service |
RFC 2702 |
Requirements for Traffic Engineering over MPLS |
RFC 2749 |
Common Open Policy Service (COPS) Usage for RSVP |
RFC 2750 |
RSVP Extensions for Policy Control |
RFC 2814 |
SBM Subnet Bandwidth Manager: A Protocol for RSVP-based Admission Control over IEEE 802-style Networks |
RFC 2961 |
RSVP Refresh Overhead Reduction Extensions |
RFC 2996 |
Format of the RSVP DCLASS Object |
Description |
Link |
---|---|
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