RSVP Application ID Support

Multiple applications such as voice and video need RSVP support. RSVP admits requests until the bandwidth limit is reached. RSVP does not differentiate between the requests and is not aware of the type of application for which the bandwidth is requested.

As a result, RSVP can exhaust the allowed bandwidth by admitting requests that represent just one type of application, causing all subsequent requests to be rejected because of unavailable bandwidth. For example, a few video calls could prevent all or most of the voice calls from being admitted because the video calls require a large amount of bandwidth and not enough bandwidth remains to accommodate the voice calls. With this limitation, you would probably not deploy RSVP for multiple applications especially if voice happens to be one of the applications for which RSVP is required.

The solution is to allow configuration of separate bandwidth limits for individual applications or classes of traffic. Limiting bandwidth per application requires configuring a bandwidth limit per application and having each reservation flag the application to which the reservation belongs so that it can be admitted against the appropriate bandwidth limit.

Application and Sub Application Identity Policy Element for Use with RSVP (IETF RFC 2872) allows for creation of separate bandwidth reservation pools. For example, an RSVP reservation pool can be created for voice traffic, and a separate RSVP reservation pool can be created for video traffic. This prevents video traffic from overwhelming voice traffic.

Note

Before this feature, you could create access control lists (ACLs) that match on the differentiated services code points (DSCPs) of the IP header in an RSVP message. However, multiple applications could use the same DSCP; therefore, you could not uniquely identify applications in order to define separate policies for them.

The figure below shows a sample solution in which application ID is used. In this example, bandwidth is allocated between the voice and video sessions that are being created by Cisco CallManager (CCM). Video requires much more bandwidth than voice, and if you do not separate the reservations, the video traffic could overwhelm the voice traffic.

CCM has been enhanced to use the RSVP Application ID Support feature. In this example, when CCM makes the RSVP reservation, CCM has the ability to specify whether the reservation should be made against a video RSVP bandwidth pool or a voice RSVP bandwidth pool. If there is not enough bandwidth remaining in the requested pool, even though there is enough bandwidth in the total RSVP allocation, RSVP signals CCM that there is a problem with the reservation. The figure shows some of the signaling and data traffic that is sent during the session setup.

IMAGE MISSING; embedded not referenced

In this scenario, the IP phones and IP video devices do not directly support RSVP. In order to allow RSVP to reserve the bandwidth for these devices, the RSVP agent component in the Cisco IOS router creates the reservation. During the setup of the voice or video session, CCM communicates with the RSVP agent and sends the parameters to reserve the necessary bandwidth.

When you want to make a voice or video call, the device signals CCM. CCM signals the RSVP agent, specifying the RSVP application ID that corresponds to the type of call, which is voice or video in this example. The RSVP agents establish the RSVP reservation across the network and tell CCM that the reservation has been made. CCM then completes the session establishment, and the Real-Time Transport Protocol (RTP) traffic streams flow between the phones (or video devices). If the RSVP agents are unable to create the bandwidth reservations for the requested application ID, they communicate that information back to CCM, which signals this information back to you.

You can configure RSVP policies globally and on a per-interface basis. You can also configure multiple global policies and multiple policies per interface.

Global RSVP policies restrict how much RSVP bandwidth a router uses regardless of the number of interfaces. You should configure a global policy if your router has CPU restrictions, one interface, or multiple interfaces that do not require different bandwidth limits.

Per-interface RSVP policies allow you to configure separate bandwidth pools with varying limits so that no one application, such as video, can consume all the RSVP bandwidth on a specified interface at the expense of other applications, such as voice, which would be dropped. You should configure a per-interface policy when you need greater control of the available bandwidth.

RSVP searches for policies whenever an RSVP message is processed. The policy tells RSVP if any special handling is required for that message.

If your network configuration has global and per-interface RSVP policies, the per-interface policies are applied first meaning that RSVP looks for policy-match criteria in the order in which the policies were configured. RSVP searches for policy-match criteria in the following order:

• Nondefault interface policies
• Default interface policy
• Nondefault global policies
• Global default policy

If RSVP finds no policy-match criteria, it accepts all incoming messages. To change this decision from accept to reject, issue the ip rsvp policy default-reject command.

Preemption happens when one reservation receives priority over another because there is insufficient bandwidth in an RSVP pool. There are two types of RSVP bandwidth pools: local policy pools and interface pools. Local policies can be global or interface-specific. RSVP performs admission control against these pools when a RESV message arrives.

If an incoming reservation request matches an RSVP local policy that has an RSVP bandwidth limit (as configured with the maximum bandwidth group submode command) and that limit has been reached, RSVP tries to preempt other lower-priority reservations admitted by that policy. When there are too few of these lower-priority reservations, RSVP rejects the incoming reservation request. Then RSVP looks at the interface bandwidth pool that you configured by using the ip rsvp bandwidth command. If that bandwidth limit has been reached, RSVP tries to preempt other lower-priority reservations on that interface to accommodate the new reservation request. At this point, RSVP does not consider which local policies admitted the reservations. When not enough bandwidth on that interface pool can be preempted, RSVP rejects the new reservation even though the new reservation was able to obtain bandwidth from the local policy pool.

Preemption can also happen when you manually reconfigure an RSVP bandwidth pool of any type to a lower value such that the existing reservations using that pool no longer fit in the pool.

• How Preemption Priorities Are Assigned and Signaled
• Controling Preemption

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip rsvp policy identity alias policy-locator locator

4.    Repeat Step 3 as needed to configure additional application IDs.

5.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	ip rsvp policy identity alias policy-locator locator Example: Router(config)# ip rsvp policy identity rsvp-voice policy-locator APP=Voice	Defines RSVP application IDs to use as match criteria for local policies. Enter a value for the aliasargument, which is a string used within the router to reference the identity in RSVP configuration commands and show displays. The string can have as many as 64 printable characters (in the range 0x20 to 0x7E). Note    If you use the " " or ? characters as part of the alias or locator string itself, you must type the CTRL/V key sequence before entering the embedded " " or ? characters. The alias is never transmitted to other routers. Enter a value for the locator argument, which is a string that is signaled in RSVP messages and contains application IDs usually in X.500 Distinguished Name (DN) format. This can also be a regular expression. For more information on regular expressions, see the Configuring an Application ID section.
Step 4	Repeat Step 3 as needed to configure additional application IDs.	Defines additional application IDs.
Step 5	end Example: Router(config)# end	Exits global configuration mode and returns to privileged EXEC mode.

• What to Do Next

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip rsvp policy local {ac l acl1 [acl2...acl8] | default | identity alias1 [alias2...alias4] | origin-as as1 [as2...as8]}

4.    Repeat Step 3 as needed to configure additional local policies.

5.    {accept | forward [all | path| path-error | resv| resv-error] | default | exit | fast-reroute | local-override | maximum [bandwidth [group x] [single y] | senders n]| preempt-priority [traffic-eng x] setup-priority [hold-priority]}

6.    Repeat Step 5 as needed to configure additional submode commands.

7.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	ip rsvp policy local {ac l acl1 [acl2...acl8] | default | identity alias1 [alias2...alias4] | origin-as as1 [as2...as8]} Example: Router(config)# ip rsvp policy local identity rsvp-voice	Creates a local policy to determine how RSVP resources are used in a network and enters local policy configuration mode. Enter the identity alias1 keyword and argument combination to specify an application ID alias.
Step 4	Repeat Step 3 as needed to configure additional local policies.	(Optional) Configures additional local policies.
Step 5	{accept | forward [all | path| path-error | resv| resv-error] | default | exit | fast-reroute | local-override | maximum [bandwidth [group x] [single y] | senders n]| preempt-priority [traffic-eng x] setup-priority [hold-priority]} Example: Router(config-rsvp-policy-local)# forward all	(Optional) Defines the properties of the local policy that you are creating. (These are the submode commands.) Note    This is an optional step. An empty policy rejects everything, which may be desired in some cases. See the ip rsvp policy local command for more detailed information on submode commands.
Step 6	Repeat Step 5 as needed to configure additional submode commands.	(Optional) Configures additional submode commands.
Step 7	end Example: Router(config-rsvp-policy-local)# end	Exits local policy configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    Repeat Step 3 as needed to configure additional interfaces.

5.    ip rsvp bandwidth [interface-kbps] [single-flow-kbps]

6.    Repeat Step 5 as needed to configure bandwidth for additional interfaces.

7.    ip rsvp policy local {ac l acl1 [acl2...acl8] | default | identity alias1 [alias2...alias4] | origin-as as1 [as2...as8]}

8.    Repeat Step 7 as needed to configure additional local policies.

9.    {accept | forward [all | path| path-error | resv| resv-error] | default | exit | fast-reroute | local-override | maximum [bandwidth [group x] [single y] | senders n] | preempt-priority [traffic-eng x] setup-priority [hold-priority]}

10.    Repeat Step 9 as needed to configure additional submode commands.

11.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	interface type number Example: Router(config)# interface Ethernet0/0	Configures the interface type and number and enters interface configuration mode.
Step 4	Repeat Step 3 as needed to configure additional interfaces.	(Optional) Configures additional interfaces.
Step 5	ip rsvp bandwidth [interface-kbps] [single-flow-kbps] Example: Router(config-if)# ip rsvp bandwidth 500 500	Enables RSVP on an interface. The optional interface-kbps and single-flow-kbps arguments specify the amount of bandwidth that can be allocated by RSVP flows or to a single flow, respectively. Values are from 1 to 1000,000.
Step 6	Repeat Step 5 as needed to configure bandwidth for additional interfaces.	(Optional) Configures bandwidth for additional interfaces.
Step 7	ip rsvp policy local {ac l acl1 [acl2...acl8] | default | identity alias1 [alias2...alias4] | origin-as as1 [as2...as8]} Example: Router(config-if)# ip rsvp policy local identity rsvp-voice	Creates a local policy to determine how RSVP resources are used in a network. Enter the identity alias1 keyword argument combination to specify an application ID alias.
Step 8	Repeat Step 7 as needed to configure additional local policies.	(Optional) Configures additional local policies.
Step 9	{accept | forward [all | path| path-error | resv| resv-error] | default | exit | fast-reroute | local-override | maximum [bandwidth [group x] [single y] | senders n] | preempt-priority [traffic-eng x] setup-priority [hold-priority]} Example: Router(config-rsvp-policy-local)# forward all	(Optional) Defines the properties of the local policy that you are creating and enters local policy configuration mode. (These are the submode commands.) Note    This is an optional step. An empty policy rejects everything, which may be desired in some cases. See the ip rsvp policy localcommand for more detailed information on submode commands.
Step 10	Repeat Step 9 as needed to configure additional submode commands.	(Optional) Configures additional submode commands.
Step 11	end Example: Router(config-rsvp-policy-local)# end	Exits local policy configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip rsvp policy identity alias policy-locator locator

4.    Repeat step 3 to configure additional application IDs.

5.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	ip rsvp policy identity alias policy-locator locator Example: Router(config)# ip rsvp policy identity rsvp-voice policy-locator "APP=Voice"	Defines RSVP application IDs to use as match criteria for local policies. Enter a value for the aliasargument, which is a string used within the router to reference the identity in RSVP configuration commands and show displays. The string can have as many as 64 printable characters (in the range 0x20 to 0x7E). Note    If you use the " " or ? characters as part of the alias or locator string itself, you must type the CTRL/V key sequence before entering the embedded " " or ? characters. The alias is never transmitted to other routers. Enter a value for the locator argument, which is a string that is signaled in RSVP messages and contains application IDs usually in X.500 Distinguished Name (DN) format. Note    Repeat this step as needed to configure additional application IDs.
Step 4	Repeat step 3 to configure additional application IDs.	Configures additional application IDs.
Step 5	end Example: Router(config)# end	Exits global configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip rsvp sender-host session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-d-port sender-s-port bandwidth burst-size [identity alias]

4.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	ip rsvp sender-host session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-d-port sender-s-port bandwidth burst-size [identity alias] Example: Router(config)# ip rsvp sender-host 10.0.0.7 10.0.0.1 udp 1 1 10 10 identity rsvp-voice	Enables a router to simulate a host generating RSVP PATH messages. The optional identity alias keyword and argument combination specifies an application ID alias. The string can have as many as 64 printable characters (in the range 0x20 to 0x7E). Note    If you use the " " or ? characters as part of the alias string itself, you must type the CTRL/V key sequence before entering the embedded " " or ? characters. The alias is never transmitted to other routers.
Step 4	end Example: Router(config)# end	Exits global configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.   Do one of the following:

4.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	Do one of the following: ip rsvp reservation-host session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-d-port sender-s-port{ff | se | wf} {rate | load} bandwidth burst-size [identity alias] ip rsvp reservation session-ip-address sender-ip-address {tcp | udp | ip-protocol} session-d-port sender-s-port next-hop-ip-address next-hop-interface {ff | se | wf} {rate | load} bandwidth burst-size[identity alias] Example: Router(config)# ip rsvp reservation-host 10.1.1.1 10.30.1.4 udp 20 30 se load 100 60 identity rsvp-voice Example: Example: Router(config)# ip rsvp reservation 10.1.1.1 0.0.0.0 udp 20 0 172.16.4.1 Ethernet1 wf rate 350 65 identity xyz	Enables a router to simulate a host generating RSVP RESV messages. The optional identity alias keyword and argument combination specifies an application ID alias. The string can have as many as 64 printable characters (in the range 0x20 to 0x7E). Note    If you use the " " or ? characters as part of the alias string itself, you must type the CTRL/V key sequence before entering the embedded " " or ? characters. The alias is never transmitted to other routers. Note    Use the ip rsvp reservation-host command if the router is the destination or the ip rsvp reservation command to have the router proxy on behalf of a downstream host.
Step 4	end Example: Router(config)# end	Exits global configuration mode and returns to privileged EXEC mode.

The following example configures R4 with a proxy receiver to create an RESV message to match the PATH message for the destination 10.0.0.7:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# ip rsvp listener 10.0.0.7 any any reply
 
Router(config)# end

The following example configures R3 with an application ID called video and a global local policy in which all RSVP messages are being accepted and forwarded:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# ip rsvp policy identity video policy-locator video
Router(config)# ip rsvp policy local identity video
Router(config-rsvp-policy-local)# forward all
Router(config-rsvp-policy-local)# end

The following example configures R2 with an application ID called video, which is a wildcard regular expression to match any application ID that contains the substring video:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# ip rsvp policy identity video policy-locator .*Video.*
Router(config-rsvp-id)# end

The following example configures R2 with a local policy on ingress Ethernet interface 0/0:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# interface Ethernet0/0
Router(config-if)# ip address 10.0.0.2 255.0.0.0
Router(config-if)# no cdp enable
Router(config-if)# ip rsvp bandwidth 200
Router(config-if)# ip rsvp policy local identity video
Router(config-rsvp-policy-local)# maximum senders 10
Router(config-rsvp-policy-local)# maximum bandwidth group 100
Router(config-rsvp-policy-local)# maximum bandwidth single 10
Router(config-rsvp-policy-local)# forward all
Router(config-rsvp-policy-local)# end

The following example configures R2 with a local policy on egress Ethernet interface 3/0:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# interface Ethernet3/0
Router(config-if)# ip address 10.0.0.3 255.0.0.0
Router(config-if)# no cdp enable
Router(config-if)# ip rsvp bandwidth 200
Router(config-if)# ip rsvp policy local identity video
Router(config-rsvp-policy-local)# maximum senders 10
Router(config-rsvp-policy-local)# maximum bandwidth group 100
Router(config-rsvp-policy-local)# maximum bandwidth single 10
Router(config-rsvp-policy-local)# forward all
Router(config-rsvp-policy-local)# end

Note	PATH messages arrive on ingress Ethernet interface 0/0 and RESV messages arrive on egress Ethernet interface 3/0.

The following example configures R1 with an application ID called video and initiates a host generating a PATH message with that application ID:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# ip rsvp policy identity video policy-locator "GUID=www.cisco.com, APP=Video, VER=1.0"
Router(config)# ip rsvp sender-host 10.0.0.7 10.0.0.1 udp 1 1 10 10 identity video 
Router(config)# end

The following example verifies that a global local policy has been configured on R3 with an application ID called Video:

Router# show ip rsvp policy local detail 
Global:
  Policy for ID(s): Video
    Preemption Scope: Unrestricted.
    Local Override:   Disabled.
    Fast ReRoute:     Accept.
    Handle:           23000404.
                           Accept               Forward
    Path:                  Yes                  Yes
    Resv:                  Yes                  Yes
    PathError:             Yes                  Yes
    ResvError:             Yes                  Yes
                           Setup Priority       Hold Priority
    TE:                    N/A                  N/A  
    Non-TE:                N/A                  N/A  
                           Current              Limit
    Senders:               1                    N/A
    Receivers:             1                    N/A
    Conversations:         1                    N/A
    Group bandwidth (bps): 10K                  N/A                 
    Per-flow b/w (bps):    N/A                  N/A                 
          
          
Generic policy settings:
    Default policy: Accept all
    Preemption:     Disabled

The following example verifies that an application ID called Video has been created on R2:

Router# show ip rsvp policy identity 
Alias: Video
  Type:    Application ID
  Locator: .*Video.*

The following example verifies that per-interface local policies have been created on Ethernet interface 0/0 and Ethernet interface 3/0 on R2:

Router# show ip rsvp policy local detail
Ethernet0/0:
  Policy for ID(s): Video
    Preemption Scope: Unrestricted.
    Local Override:   Disabled.
    Fast ReRoute:     Accept.
    Handle:           26000404.
                           Accept               Forward
    Path:                  Yes                  Yes
    Resv:                  Yes                  Yes
    PathError:             Yes                  Yes
    ResvError:             Yes                  Yes
                           Setup Priority       Hold Priority
    TE:                    N/A                  N/A  
    Non-TE:                N/A                  N/A  
                           Current              Limit
    Senders:               1                    10 
    Receivers:             0                    N/A
    Conversations:         0                    N/A
    Group bandwidth (bps): 0                    100K                
    Per-flow b/w (bps):    N/A                  10K                 
          
Ethernet3/0:
  Policy for ID(s): Video
    Preemption Scope: Unrestricted.
    Local Override:   Disabled.
    Fast ReRoute:     Accept.
    Handle:           5A00040A.
                           Accept               Forward
    Path:                  Yes                  Yes
    Resv:                  Yes                  Yes
    PathError:             Yes                  Yes
    ResvError:             Yes                  Yes
                           Setup Priority       Hold Priority
    TE:                    N/A                  N/A  
    Non-TE:                N/A                  N/A  
                           Current              Limit
    Senders:               0                    10   
    Receivers:             1                    N/A
    Conversations:         1                    N/A
    Group bandwidth (bps): 10K                  100K                
    Per-flow b/w (bps):    N/A                  10K                 
Generic policy settings:
    Default policy: Accept all
    Preemption:     Disabled

Note

Notice in the above display that the ingress interface has only its senders counter incremented because the PATH message is checked there. However, the egress interface has its receivers, conversations, and group bandwidth counters incremented because the reservation is checked on the incoming interface, which is the egress interface on R2.

The following example verifies that a PATH message containing the application ID called Video has been created on R1:

Router# show ip rsvp sender detail
PATH Session address: 10.0.0.7, port: 1. Protocol: UDP
  Sender address: 10.0.0.1, port: 1
     Inbound from: 10.0.0.1
 on interface:
  Traffic params - Rate: 10K bits/sec, Max. burst: 10K bytes
                   Min Policed Unit: 0 bytes, Max Pkt Size 4294967295 bytes
  Path ID handle: 02000402.
  Incoming policy: Accepted. Policy source(s): Default
    Application ID: 'GUID=www.cisco.com, APP=Video, VER=1.0'
  Status: Proxied
  Output on Ethernet0/0. Policy status: Forwarding. Handle: 01000403
    Policy source(s): Default

Note	You can issue the debug ip rsvp dump path and the debug ip rsvp dump resv commands to get more information about a sender and the application ID that it is using.

The following example verifies that a reservation with the application ID called Video has been created on R1:

Router# show ip rsvp reservation detail
 
RSVP Reservation. Destination is 10.0.0.7, Source is 10.0.0.1, 
  Protocol is UDP, Destination port is 1, Source port is 1
  Next Hop is 10.0.0.2, Interface is Ethernet0/0
  Reservation Style is Fixed-Filter, QoS Service is Guaranteed-Rate
  Resv ID handle: 01000405.
  Created: 10:07:35 EST Thu Jan 12 2006
  Average Bitrate is 10K bits/sec, Maximum Burst is 10K bytes
  Min Policed Unit: 0 bytes, Max Pkt Size: 0 bytes
  Status:
  Policy: Forwarding. Policy source(s): Default
    Application ID: 'GUID=www.cisco.com, APP=Video, VER=1.0'