RSVP Agent Configuration

Greetings,

Does the RSVP agent need to be in the data path of the call in order to be invoked?

 

The issue I am trying to solve is customer has and MPLS gateway and a voice gateway.  The core switch at each location is the default gateway for all the phones.  If the call is destined for the PSTN the call goes to the PSTN Gateway, if the call is destined for the WAN it goes through the MPLS gateway.  I do not have access to the MPLS gateways thus I am wondering if I can setup the RSVP agent on the PSTN gateway even thought the call never goes through that gateway. 

In my mind it should work because the agent is just keeping track of call counts and deducting that from available bandwidth, in reality my efforts have proven to be less than successful.

Option 1: Reconfigure fhe network so that the PSTN gateway is the default gateway for my phones.The calls from soft clients ont he Data VLAN will fail do to no RSVP agent.

Option 2: Configure an MTP on the MPLS gateways.  These gateways do not have and DSPs in them so I don't think I can do this.

Are there any options I am missing?


Thanks,

Coop

Comments

  • Ahochau -

    Have you tried gaining access to the MPLS gateways?  You can use software-based MTPs for RSVP Agent.

    Also, remember that not every device in the call path needs to have RSVP enabled in order for it to work.

    Here's a snippet from the CUCM 8.x SRND:

    Cisco RSVP Agent Provisioning

    The capacity of Cisco RSVP Agent in terms of simultaneous calls (also referred to as sessions) depends on the following factors:
    • For software-based MTP functionality, the session capacity is determined by the router platform and the relative CPU load. (Refer to the Cisco RSVP Agent Data Sheet, available at http://www.cisco.com/en/US/products/ps6832/products_data_sheets_list.html.)
    • For hardware-based MTP and transcoder functionality, the session capacity is limited by the number of DSPs available. (See Media Resources, for DSP sizing considerations.) 
    For more information on supported platforms, requirements, and capacities, refer to the Cisco RSVP Agent Data Sheet, available at: http://www.cisco.com/en/US/products/ps6832/products_data_sheets_list.html

    For software-based MTP functionality, the Cisco RSVP Agent Data Sheet provides guidelines for session capacity based on a router dedicated to the Cisco RSVP Agent and 75% CPU utilization. These numbers apply to specific Cisco IOS releases and should be considered as broad guidelines. Different combinations of specific services, configurations, traffic patterns, network topologies, routing tables, and other factors can significantly affect actual performance for a specific deployment and hence reduce the number of concurrent sessions supported. Cisco recommends careful planning and validation testing prior to deploying a multi-service router in a production environment. 


    -- 
    Matthew Berry  |  +1.612.567.CCIE (2243)



    On Jul 19, 2012, at 12:51 PM, Ahochau wrote:
    Greetings, Does the RSVP agent need to be in the data path of the call in order to be invoked? The issue I am trying to solve is customer has and MPLS gateway and a voice gateway. The core switch at each location is the default gateway for all the phones. If the call is destined for the PSTN the call goes to the PSTN Gateway, if the call is destined for the WAN it goes through the MPLS gateway. I do not have access to the MPLS gateways thus I am wondering if I can setup the RSVP agent on the PSTN gateway even thought the call never goes through that gateway. In my mind it should work because the agent is just keeping track of call counts and deducting that from available bandwidth, in reality my efforts have proven to be less than successful. Option 1: Reconfigure fhe network so that the PSTN gateway is the default gateway for my phones.The calls from soft clients ont he Data VLAN will fail do to no RSVP agent. Option 2: Configure an MTP on the MPLS gateways. These gateways do not have and DSPs in them so I don't think I can do this. Are there any options I am missing? Thanks, Coop


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  • Thanks.

    So the bottom line is, the RSVP agent MUST be in the call path?

  • Yes.

    Refer to the CUCM SRND:

    Not all routers on the path are required to support RSVP because the protocol is designed to operate transparently across RSVP-unaware nodes. On each RSVP-enabled router, the RSVP process intercepts the signaling messages and interacts with the QoS manager for the router's outbound interface involved in the data flow in order to "reserve" bandwidth resources. When the available resources are not sufficient for the data flow anywhere along the path, the routers signal the failure back to the application that originated the reservation request.


    -- 
    Matthew Berry  |  +1.612.567.CCIE (2243)
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