> LNS Service Configuration Mode Commands
> The LNS Service Configuration Mode is used to create and manage L2TP services within contexts on the system. LNS services facilitate tunneling with peer LACs.
> Important: The commands or keywords/variables that are available are dependent on platform type, product version, and installed license(s).
> aaa accounting
> Enables the sending of AAA accounting information by the LNS.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> aaa accounting
> [ no ] aaa accounting
> no
> Disables this option.
> accounting
> Enables the sending of AAA accounting information for subscriber sessions by the LNS, by default is enabled.
> Usage
> Use this command to enable the sending of AAA accounting information by the LNS. By default this is enabled.
> Example
> The following command enables the sending of AAA accounting information by the LNS:
> aaa accounting
> authentication
> Configures the type of subscriber authentication for PPP sessions terminated at the current LNS.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> authentication { { [ allow-noauth ] [ chap chap_priority ] [ mschap mschap_priority ] [ pap pap_priority ] } | msid-auth }
> allow-noauth
> Default: Disabled
> This option configures the LNS to allow PPP sessions access even though they have not been authenticated. This command issued by itself causes the LNS to not attempt authentication for any PPP sessions.
> When the allow-noauth option is used in conjunction with commands specifying other authentication protocols and priorities to use, then if attempts to use those protocols fail, the system will treat the allow-noauth option as the lowest priority.
> If no authentication is allowed, then NAI construct will be implemented in order to provide accounting records for the PPP session.
> chap chap_priority
> Default: 1
> This option configures the LNS to attempt to use the Challenge Handshake Authentication Protocol (CHAP) to authenticate the PPP session.
> A chap_priority must be specified in conjunction with this option. Priorities specify which authentication protocol should be attempted first, second, third and so on.
> chap_priority must be an integer from 1 through 1000. The lower the integer, the higher the preference. CHAP is enabled by default as the highest preference.
> mschap mschap_priority
> Default: Disabled
> This option configures the LNS to attempt to use the Microsoft Challenge Handshake Authentication Protocol (MSCHAP) to authenticate the PP session.
> A mschap_priority must be specified in conjunction with this option. Priorities specify which authentication protocol should be attempted first, second, third and so on.
> mschap_priority must be an integer from 1 through 1000. The lower the integer, the higher the preference.
> pap pap_priority
> Default: 2
> This option configures the LNS to attempt to use the Password Authentication Protocol (PAP) to authenticate the PPP session.
> A pap_priority must be specified in conjunction with this option. Priorities specify which authentication protocol should be attempted first, second, third and so on.
> pap_priority must be an integer from 1 through 1000. The lower the integer, the higher the preference. PAP is enabled by default as the second highest preference.
> msid-auth
> Default: Disabled
> This option configures the LNS to attempt to authenticate the PPP session based on the Mobile Station Identity (MSID).
> Usage
> Use to specify how the LNS service should handle authentication and what protocols to use. The flexibility is given to configure this option to accommodate the fact that not every mobile will implement the same authentication protocols.
> The chassis is shipped from the factory with the LNS authentication options set as follows:

> • | allow-noauth disabled

> • | chap enabled with a priority of 1

> • | mschap disabled

> • | msid-auth disabled

> • | pap enabled with a priority of 2

> Important: At least one of the keywords must be used to complete the command.
> Example
> The following command configures the LNS service to allow no authentication for PPP sessions and would perform accounting using the default NAI-construct of username@domain:
> authentication allow-noauth
> The following command configures the system to attempt authentication first using CHAP, then MSCHAP, and finally PAP. If the allow-noauth command was also issued, when all attempts to authenticate the subscriber using these protocols failed, then the subscriber would be allowed access:
> authentication chap 1 mschap 2 pap 3
> avp map called-number apn
> This command maps an incoming AVP to a GGSN APN for authentication and authorization of the call.
> Product
> GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> { default | no } avp map called-number apn
> default
> Disables mapping.
> no
> Disables mapping.
> Usage
> For LNS calls received through a LAC, the ICRQ message includes an APN name in the Called Number AVP. This mapping function enables a GGSN system to provide RADIUS authentication/authorization via a defined APN in place of an LNS configuration. If the mapped APN has not been defined within the GGSN configuration then the call will be rejected.
> Example
> Enter the following command to enable mapping:
> avp map called-number apn
> Enter the following command to disable mapping:
> no avp map called-number apn
> bind
> This command assigns the IP address of an interface in the current context to the LNS service.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> bind ip_address [max-subscribers max_value ]
> no bind ip_address
> no
> Unassign, or unbind, the local end point to the LNS service.
> ip_address
> The IP address of an interface in the current context. This must be a valid IPv4 address, using dotted-decimal notation.
> max-subscribers max_value
> Default: 10000
> The maximum number of subscribers that can be connected to this service at any time. max_value must be an integer from 1 through 2500000.
> Usage
> Use this command to bind the IP address of an interface in the current context to the LNS service.
> Example
> The following command binds the current context interface IP address 192.168.100.10 to the current LNS service:
> bind 192.168.100.10
> The following command removes the binding of the IP address from the LNS service:
> no bind
> data sequence-number
> Enables data sequence numbering for sessions that use the current LNS service. Data sequence numbering is enabled by default.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> [no] data sequence-number
> no
> Disables data sequence numbering for sessions.
> Usage
> An L2TP data packet header has an optional data sequence numbers field. The data sequence number may be used to ensure ordered delivery of data packets. This command is used to re-enable or disable the use of the data sequence numbers for data packets.
> Example
> Use the following command to disable the use of data sequence numbering:
> no data sequence-number
> Use the following command to re-enable data sequence numbering:
> data sequence-number
> default
> This command sets the specified LAC service parameter to its default value or setting.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> default { authentication | data sequence-number | ip source-violation | keepalive-interval | load-balancing | local-receive-window | max-retransmission | max-session-per-tunnel | max-tunnel-challenge-length | max-tunnels | proxy-lcp-authentication | retransmission-timeout-first | retransmission-timeout-max | setup-timeout| single-port-mode | subscriber| trap all tunnel-authentication}
> authentication
> Sets the authentication parameters for PPP sessions to the following defaults:

> • | allow-noauth disabled

> • | chap enabled with a priority of 1

> • | mschap disabled

> • | msid-auth disabled

> • | pap enabled with a priority of 2

> data sequence-number
> Enables data sequence numbering for sessions.
> ip source-violation
> Sets the IP source violation parameters to the following defaults:

> • | drop-limit 10

> • | period 120 seconds

> • | reneg-limit 5

> keepalive-interval
> Sets the interval for send L2TP Hello keepalive if there is no control or data transactions to the default value of 60 secs.
> local-receive-window
> Sets the window size to be used for the local side for the reliable control transport to the default of 4.
> max-retransmission
> Sets the maximum number of retransmissions to the default of 5.
> max-session-per-tunnel
> Sets the maximum number of sessions per tunnel at any point in time to the default of 65535.
> max-tunnel-challenge-length
> Sets the maximum length of the tunnel challenge to the default of 16 bytes.
> max-tunnels
> Sets the maximum number of tunnels for this service to the default of 32000.
> proxy-lcp-authentication
> Sets sending of proxy LCP authentication parameters to the LNS to the default state of enabled.
> retransmission-timeout-first
> Sets the first retransmit interval to the default of 1 second.
> retransmission-timeout-max
> Sets the maximum retransmit interval to the default of 8 seconds.
> setup-timeout
> Sets the maximum time allowed for session setup to the default of 60 seconds.
> single-port-mode
> Disables assignment of only port 1107 for incoming tunnels and allows dynamic assignment of ports.
> subscriber
> Sets the name of the default subscriber configuration to use.
> tunnel-authentication
> Sets tunnel authentication to the default state of enabled.
> trap all
> Generates all supported SNMP traps.
> tunnel-switching
> Sets the ability of the LNS to create subsequent tunnels to the default of enabled.
> Usage
> Use the default command to set LAC service parameters to their default states.
> Example
> Use the following command to set the keep alive interval to the default value of 60 seconds:
> default keepalive-interval
> Use the following command to set the maximum number of sessions per tunnel to the default value of 512:
> default max-session-per-tunnel
> ip source-violation
> This command configures settings related to IP source-violation detection.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> ip source-violation { clear-on-valid-packet | drop-limit num | period secs | reneg-limit num }
> no ip source-violation clear-on-valid-packet
> clear-on-valid-packet
> Default: disabled
> Configures the service to reset the reneg-limit and drop-limit counters after receipt of a properly addressed packet.
> drop-limit num
> Default: 10
> Sets the number of allowed source violations within a detection period before forcing a call disconnect. If num is not specified, the value is set to the default.
> num can be any integer value from 1 to 1000000.
> period secs
> Default: 120
> The length of time, in seconds, for a source violation detection period to last. drop-limit and reneg-limit counters are decremented each time this value is reached.
> The counters are decremented in this manner: reneg-limit counter is reduced by one (1) each time the period value is reached until the counter is zero (0); drop-limit counter is halved each time the period value is reached until the counter is zero (0). If secs is not specified, the value is set to the default.
> secs can be any integer value from 1 to1000000.
> reneg-limit num
> Default: 5
> Sets the number of allowed source violations within a detection period before forcing a PPP renegotiation. If num is not specified, the value is set to the default.
> num can be any integer value from 1 to 1000000.
> Usage
> This function is intended to allow the operator to configure a network to prevent problems such as when a user gets handed back and forth between two PDSNs a number of times during a handoff scenario.
> This function operates in the following manner:
> When a subscriber packet is received with a source address violation, the system increments both the IP source-violation reneg-limit and drop-limit counters and starts the timer for the IP-source violation period. Every subsequent packet received with a bad source address during the IP-source violation period causes the reneg-limit and drop-limit counters to increment.
> For example, if reneg-limit is set to 5, then the system allows 5 packets with a bad source address (source violations), but on the 5th packet, it re-negotiates PPP.
> If the drop-limit is set to 10, the above process of receiving 5 source violations and renegotiating PPP occurs only once. After the second 5 source violations, the call is dropped. The period timer continues to count throughout this process.
> If at any time before the call is dropped, the configured source-violation period is exceeded, the counters for drop-limit is decremented by half and reneg-limit is decremented by 1. See period definition above.
> Example
> To set the maximum number of source violations before dropping a call to 100, enter the following command:
> ip source-violation drop-limit 100
> keepalive-interval
> This command specifies the amount of time to wait before sending a Hello keep alive message.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> keepalive-interval seconds
> no keepalive-interval
> no
> Disables the generation of Hello keep alive messages on the tunnel.
> seconds
> Default: 60
> The number of seconds to wait before sending a Hello keep alive message. The number can be configured to any integer value from 30 to 2147483648.
> Usage
> Use this command to set the amount of time to wait before sending a Hello keep alive message or disable the generation of Hello keep alive messages completely. A keep alive mechanism is employed by L2TP in order to differentiate tunnel outages from extended periods of no control or data activity on a tunnel. This is accomplished by injecting Hello control messages after a specified period of time has elapsed since the last data or control message was received on a tunnel. As for any other control message, if the Hello message is not reliably delivered then the tunnel is declared down and is reset. The transport reset mechanism along with the injection of Hello messages ensures that a connectivity failure between the LNS and the LAC is detected at both ends of a tunnel.
> Example
> Use the following command to set the Hello keep alive message interval to 120 seconds:
> keepalive-interval 120
> Use the following command to disable the generation of Hello keep alive messages:
> no keepalive-interval
> local-receive-window
> Specifies the number of control messages the remote peer LAC can send before waiting for an acknowledgement.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> local-receive-window integer
> integer
> Default: 4
> The number of control messages to send before waiting for an acknowledgement. The number can be configured to any integer value from 1 through 256.
> Usage
> Use this command to set the size of the control message receive window being offered to the remote peer LAC. The remote peer LAC may send the specified number of control messages before it must wait for an acknowledgment.
> Example
> The following command sets the local receive window to 10 control messages:
> local-receive-window 10
> max-retransmission
> Sets the maximum number of retransmissions of a control message to a peer before the tunnel and all sessions within it are cleared.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> max-retransmission integer
> integer
> Default: 5
> The maximum number of retransmissions of a control message to a peer. This value must be an integer from 1 through 10.
> Usage
> Each tunnel maintains a queue of control messages to be transmitted to its peer. After a period of time passes without acknowledgement, a message is retransmitted. Each subsequent retransmission of a message employs an exponential backoff interval. For example; if the first retransmission occurs after 1 second, the next retransmission occurs after 2 seconds has elapsed, then the next after 4 seconds. If no peer response is detected after the number of retransmissions set by this command, the tunnel and all sessions within are cleared.
> Use this command to set the maximum number of retransmissions that the LAC service sends before closing the tunnel and all sessions within. it.
> Example
> The following command sets the maximum number of retransmissions of a control message to a peer to 7:
> max-retransmissions 7
> max-session-per-tunnel
> Sets the maximum number of sessions that can be facilitated by a single tunnel at any time.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> max-sessions-per-tunnel integer
> integer
> Default: 512
> The maximum number of sessions. This value must be from 1 through 65535.
> Usage
> Use this command to set the maximum number of sessions you want to allow in a tunnel.
> Example
> The following command sets the maximum number of sessions in a tunnel to 5000:
> max-sessions-per-tunnel 5000
> max-tunnel-challenge-length
> Sets the maximum length of the tunnel challenge in bytes.The challenge is used for tunnel authentication purposes during tunnel creation.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> max-tunnel-challenge-length bytes
> bytes
> Default: 16
> The number of bytes to set the maximum length of the tunnel challenge. This must be a value from 4 through 32.
> Usage
> Use this command to set the maximum length, in bytes, for the tunnel challenge that is used during tunnel creation.
> Example
> The following command sets the maximum length of the tunnel challenge to 32 bytes:
> max-tunnel-challenge-length 32
> max-tunnels
> The maximum number of tunnels that the current LNS service can support.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> max-tunnels integer
> integer
> Default: 32000
> The maximum number of tunnels. This value must be an integer from 1 to 32000.
> Usage
> Use this command to set the maximum number tunnels that this LNS service can support at any one time.
> Example
> Use the following command to set the maximum number of tunnels for the current LNS service to 20000:
> max-tunnels 20000
> nai-construction domain
> Designates the alias domain name to use for Network Access Identifier (NAI) construction.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> nai-construction domain domain_name { @ | % | - | \ | # | / }
> no nai-construction domain
> no
> Deletes the NAI construction domain alias.
> domain_name { @ | % | - | \ | # | / }
> The desired domain name alias followed immediately by a separator from the valid list. domain_name must be a string of from 1 through 79 alphanumeric characters.
> Usage
> Use this command to specify the domain alias and separator to use for NAI construction. The specified domain name must be followed by a valid separator (@ | % | - | \ | # | /).
> Example
> To specify a domain alias of mydomain with a separator of @, enter the following command:
> nai-construction domain mydomain@
> To delete the current setting for the NAI construction domain alias, enter the following command:
> no nai-construction domain
> peer-lac
> Adds a peer LAC address for the current LNS service. Up to 8 peer LACs can be configured for each LNS service.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> peer-lac { ip_address | ip_address/mask } [ encrypted ] secret secret [ description text ]
> no peer-lac ip_address
> no peer-lac ip_address
> Deletes the peer LAC IP address specified by ip_address. ip_address must be entered in standard IPv4 dotted decimal notation.
> ip_address
> The IP address of a specific peer LAC for the current LNS service. ip_address must be entered in standard IPv4 dotted decimal notation.
> ip_address/mask
> A network prefix and mask enabling communication with a group of peer LACs. ip_address is the network prefix expressed in dotted decimal notation.
> mask is the number of bits that defines the prefix.
> [encrypted]
> Specifies the encrypted shared key between the LAC and the LNS service.
> This keyword is intended only for use by the system while saving configuration scripts. The system displays the encrypted keyword in the configuration file as a flag that the variable following the secret keyword is the encrypted version of the plain text secret. Only the encrypted secret is saved as part of the configuration file.
> secret secret
> Designates the secret which is shared between the current LNS service and the peer LAC. secret must be a string from 1 to 127 alpha and/or numeric characters and is case sensitive.
> description text
> Specifies the descriptive text to use to describe the specified peer LAC. text must be 0 to 79 alpha and/or numeric characters with no spaces or a quoted string of printable characters.
> Usage
> Use this command to add a peer LAC address for the current LNS service.
> Specific peer LACs can be configured by specifying their individual IP addresses. In addition, to simplify configuration, communication with a group of peer LACs can be enabled by specifying a network prefix and a mask.
> Example
> The following command adds a peer LAC to the current LNS service with the IP address of 10.10.10.100, and specifies the shared secret to be 1b34nnf5d:
> peer-lac 10.10.10.100 secret 1b34nnf5d
> The following command enables communication with up to 16 peer LACs on the 192.168.1.0 network each having a secret of abc123:
> peer-lac 192.168.1.0/28 secret abc123
> The following command removes the peer LAC with the IP address of 10.10.10.200 for the current LNS service:
> no peer-lac 10.10.10.200
> proxy-lcp-authentication
> Enables/disables proxy LCP authentication.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> [no] proxy-lcp-authentication
> no
> Disables the processing of proxy LCP authentication parameters from the LAC.
> proxy-lcp-authentication
> Default: Enabled
> Enables the processing proxy LCP authentication parameters from the LAC.
> Usage
> When enabled, if proxy LCP authentication parameters are received from the LAC and are acceptable, the LNS resumes the PPP session from the authentication phase and goes to the IPCP phase.
> When disabled, PPP is always started from the LCP phase, ignoring and discarding any proxy LCP authentication parameters received from the LAC. Disable this feature in situations where accept proxy LCP Auth AVPs that the peer LAC sends should not be expected.
> Example
> Use the following command to disable the processing of proxy LCP authentication parameters from the LAC:
> no proxy-lcp-authentication
> Use the following command to re-enable the processing of proxy LCP authentication parameters from the LAC:
> proxy-lcp-authentication
> retransmission-timeout-first
> Configures the initial timeout for the retransmission of control messages to the peer LAC.
> Privilege
> Security Administrator, Administrator
> Syntax
> retransmission-timeout-first integer
> integer
> Default: 1
> The amount of time to wait before sending the first control message retransmission. This value is measured in seconds and must be an integer from 1 to 100.
> Usage
> Each tunnel maintains a queue of control messages to transmit to its peer. After a period of time passes without acknowledgement, a message is retransmitted.
> Example
> The following command sets the initial retransmission timeout to 3 seconds:
> retransmission-timeout-first 3
> retransmission-timeout-max
> Configures the maximum amount of time that can elapse before retransmitting control messages to the peer LAC.
> Privilege
> Security Administrator, Administrator
> Syntax
> retransmission-timeout-max integer
> integer
> Default: 8
> The maximum time to wait before retransmitting control messages. If this limit is reached, the tunnel, and all sessions within it, is cleared. This value is measured in seconds and must be an integer in the range of 1 to 100.
> Usage
> Each tunnel maintains a queue of control messages to transmit to its peer. After a period of time passes without acknowledgement, a message is retransmitted. Each subsequent retransmission of a message employs an exponential backoff interval. For example; if the first retransmission occurs after 1 second, the next retransmission occurs after 2 seconds has elapsed, then the next after 4 seconds. This continues until the limit set by this command is reached. If this limit is reached, the tunnel, and all sessions within it, is cleared.
> Example
> Use the following command to set the maximum retransmission time-out to 10 seconds:
> retransmission-timeout-max 10
> setup-timeout
> Configures the maximum amount of time, in seconds, allowed for session setup.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> setup-timeout seconds
> seconds
> Default: 60
> The maximum time to wait, in seconds, for the setup of a session. seconds must be an integer from 1 through 1000000.
> Usage
> This command controls the amount of time allowed for tunnel establishment with a peer LAC. If this timer is exceeeded the tunnel setup is aborted.
> Example
> The following command configures a maximum setup time of 120 seconds:
> setup-timeout 120
> single-port-mode
> When enabled, this command sets the LNS to use only the default local UDP port (port 1701) for the life of a tunnel.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> [no | default] single-port-mode
> no
> Disable single port mode
> Usage
> Use this command to control the L2TP LNS tunnel local UDP port assignment mode. If single-port-mode is enabled, the LNS-service uses the standard UDP port (port 1701) for the life of the incoming tunnel. Otherwise, it assigns a new local UDP port number for a tunnel when it responds to a tunnel create request received on the standard port number. This is done for load distributing the tunnel processing between multiple tasks within the system to increase the capacity and performance. Even though all L2TP LACs are required to support such dynamic port assignments during tunnel establishments, there exist some LACs that do not support port assignment other than port 1701. This single-port-mode feature can be enabled to support such LAC peers. This configuration must be applied for the LNS-Service before the bind command is executed.
> Example
> The following command enables single port mode for the current LNS service:
> single-port-mode
> trap
> This command generates SNMP traps.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> [no] trap all
> no
> Disables SNMP traps.
> Usage
> Use this command to enable/disable all supported SNMP traps.
> Example
> To enable all supported SNMP traps, enter the following command;
> trap all
> tunnel-authentication
> Enables/disables L2TP tunnel authentication for the LNS service.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> [no] tunnel-authentication
> no
> Disables tunnel authentication
> Tunnel authentication is enabled by default.
> Usage
> When tunnel authentication is enabled, a configured shared secret is used to ensure that the LNS service is communicating with an authorized peer LAC. The shared secret is configured by the peer-lac command, the tunnel l2tp command in the Subscriber Configuration mode, or the Tunnel-Password attribute in the subscribers RADIUS profile.
> Example
> To disable tunnel authentication, use the following command:
> no tunnel-authentication
> To re-enable tunnel authentication, use the following command:
> tunnel-authentication
> tunnel-switching
> Enables/disables the LNS service from creating tunnels to another LAC for an existing tunnel.
> Product
> PDSN, GGSN
> Privilege
> Security Administrator, Administrator
> Syntax
> [no] tunnel-switching
> no
> Disable tunnel switching.
> Tunnel switching is enabled by default.
> Usage
> Tunnel switching is when the LNS has a tunnel connected to a LAC and creates a tunnel to a different LAC and routes the data from the original LAC through the new tunnel to the other LAC.
> Example
> To disable tunnel switching in the LNS, enter the following command;
> no tunnel-switching

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