Cisco ASR 5000 Series, Обзор продукта

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HRPD Serving Gateway Overview
Features and Functionality - Optional Enhanced Feature Software ▀
Cisco ASR 5000 Series Product Overview ▄
OL-22938-02
RFC 2406, IP Encapsulating Security Payload (ESP)
RFC 2409, The Internet Key Exchange (IKE)
In order to provision VoIP services over an e-HRPD network the StarOS 9.0 release adds support for ROHC
compression contexts over IPv6 datagrams using the RTP profile over S067 auxiliary A10' connections. The e-HRPD
application uses pre-established SO67 A10' connections for VoIP bearers. A header compression context is allocated for
the first time when a new SO67 A10' connection request comes with negotiated ROHC parameters.
In order to optimize memory allocation and system performance, the HSGW uses configured inactivity time of traffic
over the bearer to dynamically determine when the ROHC compression context should be removed. This feature is also
useful for preserving compression contexts on intra-HSGW call hand-offs. The dynamic header compression context
parameters are configured in the ROHC profile that is associated with the subscriber session.
Important:
For more information on IP header compression support, refer IP Header Compression chapter in
System Enhanced Feature Configuration Guide.
Traffic Policing and Shaping
Traffic policing and shaping allows you to manage bandwidth usage on the network and limit bandwidth allowances to
subscribers. Shaping allows you to buffer excesses to be delivered at a later time.
Traffic Policing
Traffic policing enables the configuring and enforcing of bandwidth limitations on individual subscribers and/or APNs
of a particular traffic class in 3GPP/3GPP2 service.
Bandwidth enforcement is configured and enforced independently on the downlink and the uplink directions.
A Token Bucket Algorithm (a modified trTCM) [RFC2698] is used to implement the Traffic-Policing feature. The
algorithm used measures the following criteria when determining how to mark a packet:
Committed Data Rate (CDR): The guaranteed rate (in bits per second) at which packets can be
transmitted/received for the subscriber during the sampling interval.
Peak Data Rate (PDR): The maximum rate (in bits per second) that subscriber packets can be
transmitted/received for the subscriber during the sampling interval.
Burst-size: The maximum number of bytes that can be transmitted/received for the subscriber during the
sampling interval for both committed (CBS) and peak (PBS) rate conditions. This represents the maximum
number of tokens that can be placed in the subscriber‘s ―bucket‖. Note that the committed burst size (CBS)
equals the peak burst size (PBS) for each subscriber.
The system can be configured to take any of the following actions on packets that are determined to be in excess or in
violation:
Drop: The offending packet is discarded.
Transmit: The offending packet is passed.
Lower the IP Precedence: The packet‘s ToS bit is set to ―0‖, thus downgrading it to Best Effort, prior to passing
the packet. Note that if the packet‘s ToS bit was already set to ―0‖, this action is equivalent to ―Transmit‖.