Network QoS policies

This section describes Dedicated bearers functionality

For general information about network QoS policies support, see the following topics in the 7450 ESS, 7750 SR, 7950 XRS, and VSR Quality of Service Guide, "Network QoS Policies":

  • Network QoS policies overview

  • Network ingress

    • Network ingress tunnel QoS override

    • Network ingress IP match criteria

  • Network egress

  • Basic configurations

  • Service management tasks

For descriptions of network QoS policy commands, see the 7450 ESS, 7750 SR, 7950 XRS, and VSR Classic CLI Command Reference Guide and the 7450 ESS, 7750 SR, 7950 XRS, and VSR Clear, Monitor, Show, and Tools CLI Command Reference Guide.

Dedicated bearers

A default bearer is established when the node first attaches to a cellular network for each cellular port that has an enabled SIM. An IP address is assigned for each default bearer and the node uses this IP address for the associated PDN router interface that is used to route traffic to and from the cellular network. See the PDN router interfaces section for information about PDN router interfaces and IP address assignment.

In addition to the default bearer, the node accepts network-initiated dedicated bearer establishment. The node does not initiate dedicated bearers toward the network.

Dedicated bearers provide a dedicated tunnel for specific types of traffic depending QoS requirements. Because they are established for the same cellular port as the default bearer, dedicated bearers use the same PDN router interface configured for the default bearer for sending and receiving traffic. Dedicated bearers can be a guaranteed bit rate (GBR) or non-GBR, whereas the default bearer can only be non-GBR. Dedicated bearers use traffic flow templates (TFTs) to provide special treatment to specific services that need to use the dedicated bearers.

The network programs TFTs on the cellular interface for each dedicated bearer. The TFTs contains at least one and up to eight packet filter items as follows:

  • source address (with subnet mask)

  • IP protocol number (TCP, UDP)

  • destination port range

  • source port range

  • IPSec Security Parameter Index (SPI)

  • type of Service (TOS) (IPv4)

  • Flow-Label (IPv6 only)

  • evaluation precedence index

The node expects only one TFT to be programmed by the network for each dedicated bearer. More than one TFT per dedicated bearer is not supported.

The node expects that the TFT programmed per dedicated bearer will contain only a TOS packet filter. Other TFT parameters, if they are specified and programmed, are not supported. The TOS packet filter enables mapping of egress packets that match the TOS settings to the corresponding dedicated bearer and provide GBR, or non-GBR, service for the traffic as required.

Operators must coordinate with their wireless service providers and subscribe for dedicated bearers with the specific TOS packet filter settings as required. Operators must then ensure that service ingress classification and marking for the respective traffic flows match the dedicated bearer TOS packet filter when services traffic must egress the radio interface on the dedicated bearer.

Dedicated bearer and differentiated services over a cellular network illustrates a typical use case for dedicated bearers to differentiate services over a cellular network.

Figure 1. Dedicated bearer and differentiated services over a cellular network

The following CLI output shows an example of bearer information configured on a cellular port.

*A:Dut-E# show port 1/1/1 
===============================================================================
Cellular Interface
===============================================================================
...
==================================================================
Bearer Information
==================================================================
Bearer Id   Bearer Type   QCI   UL GBR   UL MBR   DL GBR   DL MBR
------------------------------------------------------------------
        5       default     5                                    
        6     dedicated     1      100      200     1000    50000
        7     dedicated     9                                    
==================================================================
==========================================================
Traffic Flow Template Packet Filters
==========================================================
Bearer Id   Filter Id   Precedence   Direction   TOS/Mask
----------------------------------------------------------
        6           1            1      uplink    0xc0/fc
        6           2            2    downlink    0x04/fc
        7           1          200        both           
==========================================================