Multilink PPP over Frame Relay

Posted by October 11, 2011 in HDLC & PPP

Scenario:

You are the senior network engineer working at a major frame relay ISP somewhere in Europe. One of your customers requests the company to run authentication over their frame relay connections and they would also like to see fragmentation. You know there is no way to do authentication with frame-relay so you decide to bundle their PVCs in a multilink PPP setup.

Goals:

  • There are two PVCs using DLCI 102 + 201 and DLCI 112 + 211.
  • Configure Multilink PPP to run over both PVCs. Use network 192.168.12.0 /24.
  • Ensure packets will be fragmented on both serial links.
  • Configure CHAP authentication for the PPP Multilink configuration.
  • Ensure both routers can reach each others loopback0 interfaces through the PPP Multilink.

IOS:

c3640-jk9s-mz.124-16.bin

Topology:

PPP Multilink

Video Solution:

Configuration Files

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8 Comments

  1. Hi Rene
    the soultion seems to be incorrect.

    i tested the final config it did not work.

    Frank(config-if)#no frame-relay interface-dlci 201 ppp Virtual-Template1

    Pim#pi 2.2.2.2 so lo0

    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
    Packet sent with a source address of 1.1.1.1
    …..
    Success rate is 0 percent (0/5)

    my solution
    (pasting only multilink configs)

    ***Frank Config***
    interface Serial0/0
    no ip address
    encapsulation frame-relay
    serial restart-delay 0
    frame-relay interface-dlci 201 ppp Virtual-Template1
    !
    interface Serial0/1
    no ip address
    encapsulation frame-relay
    serial restart-delay 0
    frame-relay interface-dlci 211 ppp Virtual-Template2
    !

    interface Virtual-Template1
    no ip address
    ppp multilink
    ppp multilink group 1
    !
    interface Virtual-Template2
    no ip address
    ppp multilink
    ppp multilink group 1
    !
    interface Multilink1
    ip address 192.168.12.2 255.255.255.0
    ppp multilink
    ppp multilink group 1
    !

    ***Pim Config***
    interface Serial0/0
    no ip address
    encapsulation frame-relay
    serial restart-delay 0
    frame-relay interface-dlci 102 ppp Virtual-Template1
    frame-relay interface-dlci 112 ppp Virtual-Template2
    !
    interface Virtual-Template1
    no ip address
    ppp multilink
    ppp multilink group 1
    !
    interface Virtual-Template2
    no ip address
    ppp multilink
    ppp multilink group 1
    !
    interface Multilink1
    ip address 192.168.12.1 255.255.255.0
    ppp multilink
    ppp multilink group 1

    even when i shut one serial link on Frank still i am able to ping the loopbacks.

    Thanks
    Shoeb

  2. contd…
    interface Multilink1
    ip address 192.168.12.2 255.255.255.0
    ppp multilink
    ppp multilink group 1
    !

    ***Pim Config***
    interface Serial0/0
    no ip address
    encapsulation frame-relay
    serial restart-delay 0
    frame-relay interface-dlci 102 ppp Virtual-Template1
    frame-relay interface-dlci 112 ppp Virtual-Template2
    !
    interface Virtual-Template1
    no ip address
    ppp multilink
    ppp multilink group 1
    !
    interface Virtual-Template2
    no ip address
    ppp multilink
    ppp multilink group 1
    !
    interface Multilink1
    ip address 192.168.12.1 255.255.255.0
    ppp multilink
    ppp multilink group 1
    !

    even after shut one serial link on Frank , i was able to continue pinging the loopbacks.

    Thanks
    Shoeb

    1. Hi Shoeb,

      Not sure what’s wrong with my config then, that’s the one I uploaded after recording the video. Your config looks good 🙂

      Rene

  3. i noticed when you did a show frame pvc on 211 it shows up as deleted and input packest and output packest are inconsitent and finally not working

  4. PIM：config
    interface Serial0/0
    no ip address
    encapsulation frame-relay
    serial restart-delay 0
    frame-relay interface-dlci 102 ppp Virtual-Template1
    frame-relay interface-dlci 112 ppp Virtual-Template1
    no frame-relay inverse-arp
    interface Virtual-Template1
    ip address 192.168.12.1 255.255.255.0
    ppp multilink
    ppp multilink fragment delay 20
    ppp multilink interleave
    !
    no ip http server
    no ip http secure-server
    ip route 2.2.2.0 255.255.255.0 192.168.12.2
    !

    Frank：config
    interface Multilink1
    ip address 192.168.12.2 255.255.255.0
    ppp multilink
    ppp multilink fragment delay 20
    ppp multilink interleave
    ppp multilink group 1
    !
    interface Serial0/0
    no ip address
    encapsulation frame-relay
    serial restart-delay 0
    frame-relay interface-dlci 201 ppp Virtual-Template1
    no frame-relay inverse-arp
    !
    interface Serial0/1
    no ip address
    encapsulation frame-relay
    serial restart-delay 0
    frame-relay interface-dlci 211 ppp Virtual-Template2
    no frame-relay inverse-arp

    interface Virtual-Template1
    no ip address
    ppp multilink
    ppp multilink fragment delay 20
    ppp multilink interleave
    ppp multilink group 1
    !
    interface Virtual-Template2
    no ip address
    ppp multilink
    ppp multilink fragment delay 20
    ppp multilink interleave
    ppp multilink group 1
    !
    no ip http server
    no ip http secure-server
    ip route 1.1.1.0 255.255.255.0 192.168.12.1

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