Multilink PPP

The point of Multilink PPP is to take multiple PPP links and “bond” them together to act as a single PPP link. These PPP links that are being bonded could be an ISDN BRI circuit, T1 circuits, or other types of PPP circuits. Also, with multilink PPP, it can breaks large packets into smaller pieces, and send them other multiple physical links simulataneously.

Configuration example

Multilink PPP over Frame Relay (MLPPPoFR)

Configuration
R1
interface Multilink1
 ip address 192.168.1.1 255.255.255.0
 ppp multilink
 ppp multilink interleave
 ppp multilink group 1
!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial0/0
 no ip address
 encapsulation frame-relay
 clock rate 2000000
 frame-relay map ip 192.168.1.2 102
 frame-relay interface-dlci 102 ppp Virtual-Template1
 no frame-relay inverse-arp
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial0/1
 no ip address
 encapsulation frame-relay
 clock rate 2000000
 frame-relay map ip 192.168.1.2 102
 frame-relay interface-dlci 102 ppp Virtual-Template1
!
interface Virtual-Template1
 ip address 192.168.1.1 255.255.255.0
 ppp multilink
 ppp multilink interleave
 ppp multilink group 1
!

R2

interface Multilink1
 ip address 192.168.1.2 255.255.255.0
 ppp multilink
 ppp multilink interleave
 ppp multilink group 1
!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial0/0
 no ip address
 encapsulation frame-relay
 clock rate 2000000
 frame-relay map ip 192.168.1.1 201
 frame-relay interface-dlci 201 ppp Virtual-Template1
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial0/1
 no ip address
 encapsulation frame-relay
 shutdown
 clock rate 2000000
 frame-relay map ip 192.168.1.1 201
 frame-relay interface-dlci 201 ppp Virtual-Template1
!
interface Virtual-Template1
 no ip address
 ppp multilink
 ppp multilink interleave
 ppp multilink group 1

Verify Configuration

Router#show ppp multilink

Multilink1

  Bundle name: Router

  Remote Endpoint Discriminator: [1] Router

  Local Endpoint Discriminator: [1] Router

  Bundle up for 00:10:20, total bandwidth 100000, load 1/255

  Receive buffer limit 12000 bytes, frag timeout 1000 ms

  Interleaving disabled

    0/0 fragments/bytes in reassembly list

    0 lost fragments, 0 reordered

    0/0 discarded fragments/bytes, 0 lost received

    0xF received sequence, 0x16 sent sequence

  Member links: 1 active, 2 inactive (max not set, min not set)

    Vi3, since 00:10:20, 375000 weight, 1496 frag size

    Vi1 (inactive)

    Vt1 (inactive)

No inactive multilink interfaces

Router#

Reference

http://www.cisco.com/en/US/docs/ios/qos/configuration/guide/mlppp_over_fr_ps6441_TSD_Products_Configuration_Guide_Chapter.html#wp1027188