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This chapter describes the commands used to configure the Point-to-Point Protocol (PPP) Bandwidth Allocation Control Protocol (BACP) for dial-up solutions on your router.
For information about configuring BACP for dial-up solutions, see the Dial Solutions Configuration Guide.
For PPP configuration on a router or an access server, refer to the "Configuring Media-Independent PPP" chapter and the "Configuring Asynchronous PPP and SLIP" chapter in the Dial Solutions Configuration Guide. For PPP commands, see the "Media-Independent PPP Commands" and the "Asynchronous PPP and SLIP Commands" chapter in the Dial Solutions Command Reference.
For more information about BACP, see RFC 2125.
To set PPP BACP call parameters, use the ppp bap call interface configuration command. To disable processing of a specific type of incoming connection, use the no form of this command.
ppp bap call {accept | request | timer seconds}
accept | Peer initiates link addition. This is the default. |
request | Local side initiates link addition. |
timer seconds | Number of seconds to wait between call requests the router sends, in the range 2 to 120 seconds. No default value is set. |
accept---Peers can initiate the addition of links to a multilink bundle.
The timer is disabled.
Interface configuration
This command first appeared in Cisco IOS Release 11.3.
This command can be included in a virtual interface template for configuring virtual interfaces or can be used to configure a dialer interface.
The following example configures a dialer interface to accept calls. Accepting calls is the default, but the command is included for the sake of the example.
interface dialer 1 ip unnumbered ethernet 0 encapsulation ppp ppp multilink bap ppp bap call accept ppp bap link types isdn analog dialer load threshold 30 ppp bap timeout pending 60
You can use the master indexes or search online to find documentation of related commands.
ppp bap callback
ppp bap drop
ppp bap link types
To enable PPP BACP callback and set callback parameters, use the ppp bap callback interface configuration command. To remove the PPP BACP callback configuration, use the no form of this command.
ppp bap callback {accept | request | timer seconds}
accept | Local router initiates link addition upon peer notification. |
request | Local router requests that a peer initiate link addition. |
timer seconds | Number of seconds to wait between callback requests the router sends, in the range 2 to 120 seconds. Disabled by default. |
Callback is disabled and no callback parameters are set.
The timer is disabled.
Interface configuration
This command first appeared in Cisco IOS Release 11.3.
The following example configures a BRI interface for active mode BACP:
interface bri 0 ip unnumbered ethernet 0 dialer load-threshold 10 either dialer map ip 172.21.13.101 name bap-peer 14085778899 encapsulation ppp ppp multilink bap ppp bap call request ppp bap callback accept no ppp bap call accept no ppp bap drop accept ppp bap pending timeout 30 ppp bap number default 5664567 ppp bap number secondary 5664568
You can use the master indexes or search online to find documentation of related commands.
ppp bap call
ppp bap drop
ppp bap link types
To set parameters for removing links from a multilink bundle, use the ppp bap drop interface configuration command. To disable a specific type of default processing, use the no form of this command.
ppp bap drop {accept | after-retries | request | timer seconds}
accept, request: Peers can initiate link removal and this router also can initiate link removal.
no ppp bap drop after-retries: The link is not dropped when there is no response to drop requests.
timer: disabled; no default value is defined.
Interface configuration
This command first appeared in Cisco IOS Release 11.3.
The no ppp bap drop accept command disables the router's ability to respond favorably to link drop requests from a peer. However, the router can still remove the link when it receives such requests.
The no ppp bap drop after-retries command is the default behavior; the ppp bap drop after-retries command must be entered explicitly to be effective.
The no ppp bap drop request command disables the router's ability to send link drop requests to a peer. However, the peer can still remove the link on its own behalf; for example, when there is too little traffic to justify keeping the link up.
The ppp bap max command specifies the maximum number of requests and retries.
The following partial example sets a 60-second wait between drop requests:
ppp bap drop timer 60
You can use the master indexes or search online to find documentation of related commands.
To specify the types of links that can be included in a specific multilink bundle, use the ppp bap link types interface configuration command. To remove a type of interface that was previously allowed to be added, use the no form of this command.
ppp bap link types [isdn] [analog]
isdn | (Optional) ISDN interfaces can be added to a multilink bundle. This is the default. |
analog | (Optional) Asynchronous serial interfaces can be added to a multilink bundle. |
isdn
Interface configuration
This command first appeared in Cisco IOS Release 11.3.
The choice of keywords must suit the interfaces configured for Multilink PPP. For example, if you have configured a dialer rotary with only ISDN interfaces, only the isdn keyword would be appropriate. If the configuration allows both ISDN and asynchronous interfaces, both isdn and analog keywords could be used; the multilink bundle could then consist of both ISDN and asynchronous links. BACP dynamically determines which interfaces are applicable.
The following example configures a dialer interface for passive mode BACP and for both ISDN and asynchronous serial links:
interface dialer 1 ip unnumbered ethernet 0 encapsulation ppp ppp multilink bap ppp bap call accept ppp bap link types isdn analog dialer load threshold 30 ppp bap timeout pending 60
You can use the master indexes or search online to find documentation of related commands.
To set upper limits on the number of retransmissions for PPP BACP, use the ppp bap max interface configuration command. To remove any retry limit, use the no form of this command.
ppp bap max {dial-attempts number | ind-retries number | req-retries number |
dial-attempts number | Maximum number of dial attempts to any destination number, in the range 1 to 3. The default is 1 dial attempt. |
ind-retries number | Maximum number of retries of a call status indication message, in the range 1 to 10. The default is 3 indication retries. |
req-retries number | Maximum number of retries for a particular request, in the range 1 to 5. The default is 3 request retries. |
dialers number | Maximum number of free dialers logged, in the range 1 to 10. The default is 5 dialers. |
1 dial attempt
3 indication retries
3 request retries
5 searches for free dialers
Interface configuration
This command first appeared in Cisco IOS Release 11.3.
In compliance with RFC 2125, the no form of this command explicitly removes any status indication retry limit and is displayed in the router configuration.
The ppp bap max dialers command works in conjunction with the interface commands dialer rotor and dialer priority which can be used to determine free dialers based upon the priority or the best available. Dialers include all interfaces that are configured under the dialer group leader (the dialer interface itself). The dialer group leader is displayed as the Master Interface in the show ppp bap group output.
BAP bases its link type and phone number decisions upon the ordering of the interfaces. This is suited to a mixed media environment of both ISDN and analog interfaces, where it may be desirable to choose the ISDN link over the asynchronous or vice versa.
Note that this also will limit the number of potential phone numbers which can be included in a CallResponse or CallbackRequest; the maximum number is limited to 20. For example, ten BRI interfaces with two numbers per interface.
The following partial example accepts the default number of attempts to dial a number and the default number of indication retries, but configures a limit of four times to send requests:
ppp bap max req-retries 4
You can use the master indexes or search online to find documentation of related commands.
dialer priority
dialer rotor
ppp bap drop
ppp bap monitor load
ppp bap timeout
show ppp bap group
To validate peer requests to add or remove links against the current bundle load and the defined dialer load threshold, use the ppp bap monitor load interface configuration command. To specify that incoming link addition requests are not to be subject to the bundle load threshold, use the no form of this command.
ppp bap monitor loadThis command has no arguments or keywords.
Enabled
Interface configuration
This command first appeared in Cisco IOS Release 11.3.
If the load is being monitored and the incoming peer requests that a link be dropped when the current traffic load is above the dialer load (that is, there is enough traffic to justify the current number of links), the router will not drop the link. In addition, when the traffic falls below the threshold, BACP tries to drop a link.
The no form of the command indicates that incoming peer requests to add a link are not subject to the bundle load threshold. However, other criteria must be met before a favorable response is sent.
The following partial example configures BACP not to validate peer requests against the current bundle load and the configured dialer load threshold:
no ppp bap monitor load
You can use the master indexes or search online to find documentation of related commands.
dialer-load threshold
To specify a local telephone number that peers can dial to establish a multilink bundle, use the ppp bap number interface configuration command. To remove a previously configured number, use the no form of this command.
ppp bap number {default phone-number | secondary phone-number}
default phone-number | Primary (base) phone number for this interface, the number that can be used for incoming dial calls. |
secondary phone-number | Telephone number for the second B channel. Applies only to BRI interfaces that have a different number for each B channel or to dialer interfaces that are BRIs. |
No base number is provided.
Interface configuration
This command first appeared in Cisco IOS Release 11.3.
If a peer requests that a number be supplied and no PPP BACP default number is defined, it might not be possible for the peer to access the interface. However, the peer can access the interface if it has the number already or the number it dialed originally is the same as the number for establishing a Multilink PPP bundle.
This command is applicable on both the dialer interface and the individual physical interfaces.
The following example configures a physical interface with both a default number and a secondary number:
interface bri 0 ip unnumbered ethernet 0 dialer load-threshold 10 either dialer map ip 172.21.13.101 name bap-peer 14085778899 encapsulation ppp ppp multilink bap ppp bap call request ppp bap callback accept no ppp bap call accept no ppp bap drop accept ppp bap pending timeout 30 ppp bap number default 5664567 ppp bap number secondary 5664568
In the following example, a PRI with no BAP number defined accepts incoming dial attempts. The PRI interface has no base phone number defined, so each attempt to add a link would result in a delta of zero being provided to the calling peer. The calling peer should then dial the same number as it originally used to establish the bundle.
interface serial 0:23 ip unnumbered Ethernet0 encapsulation ppp dialer in-band dialer idle-timeout 300 dialer-group 1 no fair-queue no cdp enable ppp authentication chap ppp multilink bap ppp bap call accept ppp bap callback request ppp bap timeout pending 20 ppp bap timeout response 2 ppp bap max dial-attempts 2 ppp bap monitor load
In the following example, a BRI interface with no BAP number defined initiates outgoing dial attempts. The BRI interface has no base phone number defined, so the number that it uses to establish the bundle is that from the dialer map, and all phone delta operations are applied to that number.
interface bri 0 ip unnumbered Ethernet0 encapsulation ppp dialer in-band dialer idle-timeout 300 dialer map ip 10.1.1.1 name bap_peer speed 56 19998884444 dialer-group 1 no fair-queue no cdp enable ppp authentication chap ppp multilink bap ppp bap call request ppp bap timeout pending 20 ppp bap timeout response 2 ppp bap max dial-attempts 2 ppp bap monitor load !
You can use the master indexes or search online to find documentation of related commands.
To specify nondefault timeout values for PPP BACP pending actions and responses, use the ppp bap timeout interface configuration command. To reset the response timeout to the default value, or to remove a pending timeout entirely, use the no form of this command.
ppp bap timeout {pending seconds | response seconds}
pending seconds | Number of seconds to wait before timing out pending actions, in the range 2 to 180 seconds. The default is 20 seconds. |
response seconds | Number of seconds to wait for a response before timing out, in the range 2 to 120 seconds. The default is 3 seconds. |
Enabled.
pending---20 seconds
response---3 seconds
Interface configuration
This command first appeared in Cisco IOS Release 11.3.
The no ppp bap timeout response command resets the timer to the default value.The no ppp bap timeout pending command removes the pending-action timeout entirely (in compliance with the BACP specification).
The following example configures BACP to wait 45 seconds before timing out pending actions:
interface dialer 1 ip unnumbered ethernet 0 encapsulation ppp ppp multilink bap ppp bap call accept ppp bap link types isdn analog dialer load threshold 30 ppp bap timeout pending 45
You can use the master indexes or search online to find documentation of related commands.
ppp bap call
ppp bap callback
ppp bap drop
ppp bap max
To enable Multilink PPP (MLP) on an interface and, optionally, to enable dynamic bandwidth allocation, use the ppp multilink interface configuration command. To disable Multilink PPP or, optionally, to disable only dynamic bandwidth allocation, use the no form of this command.
ppp multilink [bap]
bap | (Optional) Specifies bandwidth allocation control negotiation and dynamic allocation of bandwidth on a link. |
required | (Optional) Enforces mandatory negotiation of BACP for the multilink bundle. The multilink bundle is disconnected if BACP is not negotiated. |
Disabled. When BACP is enabled, the defaults are to accept calls and to set the timeout pending at 30 seconds.
Interface configuration
This command first appeared in Cisco IOS Release 11.3.
The no form of the command without the bap keyword disables both MLP and BACP on the interface.
This command applies only to interfaces that use PPP encapsulation.
PPP compression is allowed with MLP.
This command with the bap keyword must be used prior to configuring any ppp bap commands and options. If the bap required option is configured and a reject of the options is received, the multilink bundle is torn down.
When BACP negotiation is enabled by this command, the following values are used during negotiations to identify the protocols:
| Protocol | Hexadecimal Value |
|---|---|
BACP | 0xC02B |
BAP | 0xC02D |
The dialer load-threshold command is used to enable a rotary group to bring up additional links and to add them to a multilink bundle.
When MLP is configured, the dialer-load threshold 1 command no longer keeps a multilink bundle of any number of links connected indefinitely and the dialer-load threshold 2 command no longer keeps a multilink bundle of 2 links connected indefinitely. If you want a multilink bundle to be connected indefinitely, you must set a very high idle timer.
You can use the master indexes or search online to find documentation of related commands.
dialer-group
dialer idle-timeout
dialer load-threshold
encapsulation ppp
ppp authentication
ppp bap call
ppp bap timeout
ppp compress
To display configured dynamic and static dialer maps and dynamically created PPP BACP temporary static dialer maps, use the show dialer map EXEC command.
show dialer mapThis command has no arguments or keywords.
EXEC
This command first appeared in Cisco IOS Release 11.3.
The following is sample output from the show dialer map command. The dialer maps are grouped by network address. When multiple dialer maps exist for the same network address, the dialer maps differ only by phone number. In this output, the dialer maps marked "BAP" are temporary dialer maps the PPP BACP creates when a peer calls from a different phone number than is configured or when a peer calls from a number that does not appear in an existing map. The temporary dialer maps allows PPP BACP to make outgoing calls to the peers.
bap_peer# show dialer map Static dialer map ip 6.1.1.1 name peer_1 on Dialer1 Static dialer map ip 6.1.1.2 name peer_2 on Dialer1 BAP dialer map ip 6.1.1.2 name peer_2 on Dialer1 Dynamic dialer map ip 6.1.1.3 name peer_3 on Dialer1 BAP dialer map ip 6.1.1.3 name peer_3 on Dialer1
Table 135 describes the significant fields in this output.
| Field | Description |
|---|---|
Static dialer map ip 6.1.1.1 | This is a configured static dialer map to call the specified protocol address. |
name peer_1 | Name of the remote peer. |
on Dialer1 | The physical or logical dialer interface on which the static map is configured. |
BAP dialer map ip 6.1.1.2 | This is a temporary dialer map that was created by PPP BACP for the particular destination with a different phone number from that of any existing maps. It will be removed when the BACP group is removed or the last remaining map to that destination is removed. |
Dynamic dialer map ip 6.1.1.3 | Dialer map dynamically created when a peer called. |
BAP dialer map ip 6.1.1.3 name peer_3 | Temporary static dialer map created by PPP BACP when required. It will be removed when the BACP group is removed or when the dynamic dialer map disappears. |
You can use the master indexes or search online to find documentation of related commands.
dialer map
To display the configuration settings and run-time status for a multilink bundle, use the show ppp bap EXEC command.
show ppp bap {group [name] | queues}
group [name] | Displays information about all or, optionally, a specific BACP bundle group. |
queues | Displays information about the BACP queues. |
Privileged EXEC
This command first appeared in Cisco IOS Release 11.3.
The following is sample output from the show ppp bap group command for the bundle group named bap-peer:
Group bap-peer (multilink), id 35, peer has precedence, state Idle
Master interface: Dialer1
Outgoing requests: Call, Link Drop
Incoming requests: Call, Callback, Link Drop
Original number dialed 5773926
Transmit queue size threshold is not set
Peer link addition dependent upon load
Timers (secs): Call not set, Callback not set, Link Drop not set,
Response 30, Pending 20
Retries: Request 3, Dial 1, Indication no limit
Link removal after 3 link drop retries not set
Table 136 describes the significant fields in this display.
| Field | Description |
|---|---|
Group bap-peer (multilink), id 35 | Group name and internally assigned ID. "(multilink)" indicates the governing protocol. |
peer has precedence | In BACP negotiations called "race condition scenarios" in the BACP specification, this peer is deemed to have precedence over the remote peer. |
state Idle | Internal state. |
Outgoing requests | Current requests configured for outbound negotiation. |
Incoming requests | Current requests allowed inbound negotiation. |
Peer link addition dependent upon load | Router is monitoring the load and subjecting requests to the load settings. |
Timers (secs): Call not set, Callback not set, Link Drop not set, Response 30, Pending 20 | Settings for specified timers. |
Retries: Request 3, Dial 1, Indication no limit | Limits set on specified types of retransmissions. |
Link removal after 3 link drop retries not set | The link will not be removed after no response to the link removal request because default behavior was not changed and the relevant link drop parameter was not set. |
You can use the master indexes or search online to find documentation of related commands.
To display bundle information for the Multilink PPP bundles, use the show ppp multilink EXEC command.
show ppp multilinkThis command has no arguments or keywords.
EXEC
This command first appeared in Cisco IOS Release 11.2.
The following is the output when no bundles are on a system:
Router# show ppp multilink No active bundles
The following is sample output when a single Multilink PPP bundle (named rudder) is on a system:
Router# show ppp multilink Bundle rudder, 3 members, first link is BRI0: B-channel 1 0 lost fragments, 8 reordered, 0 unassigned, sequence 0x1E/0x1E rcvd/sent
The following is sample output when two active bundles are on a system. Subsequent bundles would be displayed below the previous bundle.
Router# show ppp multilink Bundle rudder, 3 members, first link is BRI0: B-Channel 1 0 lost fragments, 8 reordered, 0 unassigned, sequence 0x1E/0x1E rcvd/sent Bundle dallas, 4 members, first link is BRI2: B-Channel 1 0 lost fragments, 28 reordered, 0 unassigned, sequence 0x12E/0x12E rcvd/sent
The following example shows output when a stack group has been created. On stack group member systema, Multilink PPP bundle hansolo has bundle interface Virtual-Access4. Two child interfaces are joined to this bundle interface. The first is a local PRI channel (serial 0:4), and the second is an interface from stack group member systemb.
systema# show ppp multilink Bundle hansolo 2 members, Master link is Virtual-Access4 0 lost fragments, 0 reordered, 0 unassigned, 100/255 load 0 discarded, 0 lost received, sequence 40/66 rcvd/sent members 2 Serial0:4 systemb:Virtual-Access6 (1.1.1.1)
The following is sample output when the PPP BACP is enabled for the multilink bundle:
systema# show ppp multilink Bundle bap-peer, 1 member, Master link is Virtual-Access1 Bundle under BAP control Dialer Interface is Dialer1 0 lost fragments, 0 reordered, 0 unassigned, sequence 0x0/0x0 rcvd/sent 0 discarded, 0 lost received, 1/255 load Member links: 1 BRI0:1 Discriminators Local Remote BRI0:1 24 1
Table 137 describes significant fields when PPP BACP is enabled.
| Field | Description |
|---|---|
Bundle | Configured name of the multilink bundle. |
1 member | Number of interfaces in the group. |
Master link is Virtual-Access1 | Multilink bundle virtual interface. |
Bundle under BAP control | Multilink bundle is controlled and bandwidth is allocated by BACP. |
Dialer Interface is Dialer1 | Name of the interface that dials the calls. |
1/255 load | Load on the link in the range 1/255 to 255/255. (255/255 is a 100% load.) |
Member links: 1 | Number of child interfaces. |
BRI0:1 | Identity of the child interface. Link 1 is using physical interface BRI 0:1. |
Discriminators Local Remote BRI0:1 24 1 | LCP link discriminators, which are identifiers negotiated for each link in the bundle. This information is specific to BACP. BACP uses these discriminators to determine which link to drop during negotiations. |
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Posted: Mon Apr 26 16:19:22 PDT 1999
Copyright 1989-1999©Cisco Systems Inc.