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Note: Configuring the transmit connect speed calculation method has no effect on the operation of the L2TP Receive (RX) Speed AVP 38 or the Connect-Info RADIUS attribute [77] at the LAC. |
You can configure the method that the router uses to calculate the transmit connect speed of the subscriber’s access interface for a tunneled L2TP session. L2TP reports the transmit connect speed in L2TP Transmit (TX) Speed AVP 24. During the establishment of an L2TP tunnel session, the LAC sends AVP 24 to the LNS to convey the transmit speed of the subscriber’s access interface.
You can configure the calculation method for the transmit connect speed reported in L2TP Transmit (TX) Speed AVP 24 in any of the following ways. The first three methods—AAA domain maps, AAA tunnel groups, and RADIUS—are mutually exclusive.
In previous releases, the router calculated the transmit speed of the subscriber’s access interface based only on statically configured settings for the underlying layer 2 access interface. With this feature, you can obtain a more accurate representation of the transmit connect speed by choosing a calculation method that reflects changes to the layer 2 interface due to statically configured settings, dynamically configured settings, or QoS settings.
You can choose one of the following methods for calculating the transmit connect speed that is reported in L2TP Transmit (TX) Speed AVP 24:
The following sections describe each of these calculation methods.
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Note: Configuring the transmit connect speed calculation method has no effect on the operation of the L2TP Receive (RX) Speed AVP 38 or the Connect-Info RADIUS attribute [77] at the LAC. |
The static layer 2 method calculates the transmit connect speed of the subscriber’s access interface based on the statically configured settings for the underlying layer 2 ATM 1483 or Ethernet interface. The static layer 2 method does not reflect changes to the transmit speed of the layer 2 interface due to dynamically configured settings or to QoS.
For ATM 1483 circuits, the static layer 2 value is based on the bandwidth that the connection requires. The router uses certain traffic parameters for each service category to determine the required bandwidth for the connection. For more information about how the router computes bandwidth for ATM 1483 circuits, see the Connection Admission Control section in JUNOSe Link Layer Configuration Guide .
For Ethernet VLANs, the static layer 2 value is the advisory transmit speed of the VLAN subinterface, if configured with the vlan advisory-tx-speed command, or the speed of the underlying physical port if the advisory transmit speed is not configured.
If there is no explicit static configuration for the layer 2 interface, L2TP reports the speed of the underlying physical port as the transmit connect speed.
The dynamic layer 2 method calculates the transmit connect speed of the subscriber’s access interface based on the dynamically configured settings for the underlying layer 2 interface.
If there is no dynamic configuration for the layer 2 interface, L2TP reports the transmit connect speed based on statically configured settings. If there is no static speed configuration for the layer 2 interface, L2TP reports the speed of the underlying physical port as the transmit connect speed.
The QoS method calculates the transmit connect speed of the subscriber’s access interface based on settings determined by static or dynamic QoS configurations. This calculation is based on the interface columns that QoS uses to build scheduler profiles for L2TP sessions. For example, a typical interface column might consist of an L2TP session over an Ethernet VLAN over a Gigabit Ethernet interface.
You can configure QoS to control the rate of any logical interface in the interface column. For those logical interfaces with a rate controlled by QoS, QoS reports this configured rate as the transmit connect speed for that interface. For those logical interfaces that do not have a QoS-configured rate, QoS reports the speed of the underlying physical port as the transmit connect speed.
For more information, see QoS and L2TP TX Speed AVP 24 Overview in JUNOSe Quality of Service Configuration Guide.
The actual method calculates the transmit connect speed of the subscriber’s access interface as the lesser of the following two values:
The examples in this section illustrate how the router uses the methods described in Transmit Connect Speed Calculation Methods to calculate the transmit connect speed.
In this example, an L2TP session is established over an ATM 1483 subinterface on an OC3/STM1 ATM IOA. The configuration has the following characteristics:
Based on these characteristics, Table 67 lists the transmit connect speed value reported in L2TP Transmit (TX) Speed AVP 24 for each calculation method, and the reason why L2TP reports this value.
Table 67: Transmit Connect Speeds for L2TP over ATM 1483 Example
In this example, an L2TP session is established over a PPPoE subinterface over an Ethernet VLAN subinterface. The configuration has the following characteristics:
Based on these characteristics, Table 68 lists the transmit connect speed value reported in L2TP Transmit (TX) Speed AVP 24 for each calculation method, and the reason why L2TP reports this value.
Table 68: Transmit Connect Speeds for L2TP over Ethernet Example
The following considerations affect the transmit connect speed value reported in L2TP Transmit (TX) Speed AVP 24 when you use this feature.
Under certain heavy load conditions, the router might be unable to obtain the dynamic-layer2 value for the transmit connect speed of the subscriber’s access interface. In this situation, the LAC sends the LNS an L2TP Call-Disconnect-Notify (CDN) message to terminate the L2TP session.
For more information about supported L2TP terminate reasons, see AAA Terminate Reasons.
For interface columns that consist of an L2TP session over an Ethernet VLAN subinterface over a bridged Ethernet interface, the advisory transmit speed of the VLAN subinterface, if configured with the vlan advisory-tx-speed command, takes precedence over the physical port speed of the underlying layer 2 ATM 1483 interface. As a result, if the advisory transmit speed is configured for the VLAN subinterface, L2TP reports this value as the transmit connect speed regardless of the port speed of the ATM 1483 interface.
To configure the transmit connect speed calculation method for a tunneled L2TP session associated with an AAA domain map:
- host1(config)#aaa domain-map sunnyvale.com
- host1(config-domain-map)#router-name lac
- host1(config-domain-map)#tunnel 5
- host1(config-domain-map-tunnel)#
For more information about how to map a domain to an L2TP tunnel from Domain Map Tunnel Configuration mode, see Mapping a User Domain Name to an L2TP Tunnel Overview .
- host1(config-domain-map-tunnel)#tx-connect-speed-method
dynamic-layer2
host1(config-domain-map-tunnel)#run show aaa domain-map
Domain: sunnyvale.com; router-name: lac; ipv6-router-name: default
Tunnel
Tunnel Tunnel Tunnel Tunnel Tunnel Tunnel Tunnel Client
Tag Peer Source Type Medium Password Id Name
------ ------ ------ ------ ------ -------- ------ ------
5 <null> <null> l2tp ipv4 <null> <null> <null>
Tunnel Tunnel Tunnel
Tunnel Server Tunnel Max Virtual
Tag Name Preference Sessions Tunnel RWS Router
------ ------ ---------- -------- -------------- -------
5 <null> 2000 0 system chooses <null>
Tunnel Tunnel Tunnel
Tunnel Failover Switch Tx
Tag Resync Profile Speed Method
------ -------- ------- --------------
5 <null> <null> dynamic layer2
To configure the transmit connect speed calculation method for a tunneled L2TP session associated with an AAA tunnel group:
- host1(config)#aaa tunnel-group boston
- host1(config-tunnel-group)#tunnel 3
- host1(config-tunnel-group-tunnel)#
For more information about how to map a domain to an L2TP tunnel from Tunnel Group Tunnel Configuration mode, see Mapping a User Domain Name to an L2TP Tunnel Overview.
- host1(config-tunnel-group-tunnel)#tx-connect-speed-method
qos
host1(config-tunnel-group-tunnel)#run show aaa tunnel-group
Tunnel Group: boston
Tunnel
Tunnel Tunnel Tunnel Tunnel Tunnel Tunnel Tunnel Client
Tag Peer Source Type Medium Password Id Name
------ ------ ------ ------ ------ -------- ------ ------
3 <null> <null> l2tp ipv4 <null> <null> <null>
Tunnel Tunnel Tunnel
Tunnel Server Tunnel Max Virtual
Tag Name Preference Sessions Tunnel RWS Router
------ ------ ---------- -------- -------------- -------
3 <null> 2000 0 system chooses <null>
Tunnel
Tunnel Tunnel Tx
Tunnel Failover Switch Speed
Tag Resync Profile Method
------ -------- ------- ------
3 <null> <null> qos
You can configure the transmit connect speed calculation method as a default AAA tunnel parameter by using the aaa tunnel tx-connect-speed-method command from Global Configuration mode. This command applies the specified calculation method to all tunneled L2TP sessions associated with a particular virtual router, and thereby alleviates the need for you to configure the transmit connect speed calculation method for each individual subscriber.
Configuring the calculation method as a default AAA tunnel parameter for a virtual router has lower precedence than using AAA domain maps, AAA tunnel groups, or RADIUS to configure the transmit connect speed calculation method. The router uses the calculation method specified with the aaa tunnel tx-connect-speed-method command if the tunnel attributes returned from an AAA domain map, an AAA tunnel group, or a RADIUS authentication server do not include the transmit connect speed calculation method.
To configure the transmit connect speed calculation method for all tunneled L2TP sessions associated with a particular virtual router:
- host1(config)#virtual-router north
For more information about configuring and using virtual routers, see the Configuring Virtual Routers chapter in JUNOSe System Basics Configuration Guide.
- host1:north(config)#aaa tunnel tx-connect-speed-method
qos
host1:north(config)#run show aaa tunnel-parameters Tunnel password is <NULL> Tunnel client-name is <NULL> Tunnel nas-port-method is none Tunnel switch-profile is boston Tunnel tx-connect-speed-method is qos Tunnel nas-port ignore disabled Tunnel nas-port-type ignore disabled Tunnel assignmentId format is assignmentId Tunnel calling number format is fixed
On the LAC, the router can receive tunnel configuration attributes through a RADIUS authentication server. To use RADIUS to configure the transmit connect speed calculation method for a subscriber’s access interface, you can configure RADIUS to include the Tunnel-Tx-Speed-Method RADIUS attribute (Juniper Networks VSA 26-94) in RADIUS Access-Accept messages.
Table 69 describes the Tunnel-Tx-Speed-Method RADIUS attribute. For more information about RADIUS Access-Accept messages, see Configuring RADIUS Attributes. For a description of the RADIUS attributes supported by JUNOSe software, see RADIUS IETF Attributes.
Table 69: Tunnel--Tx-Speed-Method RADIUS Attribute
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