Multilink Frame Relay (MFR) and Multilink PPP


Multilink Frame Relay (MFR) and Multilink PPP

Don’t understand why but MFR and PPP would always confuse me a lot and the idea behind it is rather simple.

MFR and PPP are cisco features that allow to  increase bandwidth and resiliency with the layer 3 result appearing as a single Layer 3 link between nodes using multiple WAN links.Multilink frame operates in much the same fashion that multilink PPP uses. Individual circuits are logically tied together, creating a bundle. This bundle is what gets addressed on the router.The basic idea is to take several frame-relay interfaces with the same DLCI and bundle them into one logical interface. Kind of like an Etherchannel. The reason for this post is that the DOCCD isn’t really intuitive for this topic and there does not seem to be a lot of documentation how to configure this rather simple feature.

  • MFR

Interfaces S0/0 and S0/1  on both devices will be used for MRF (since we’re not using a Frame Switch we’re going to turn FR LMI off)

R1
int mfr 1
no keepalive
no shut
int s0/0
shutdown
encapsulation frame-relay mfr 1
no shut
int s0/1
shutdown
encapsulation frame-relay mfr 1
no shut
int mfr1.12 point-to-point
ip address 172.16.10.1 255.255.255.0
frame-relay interface-dlci 47

R2
int mfr 1
no keepalive
no shut
int s0/0
shutdown
encapsulation frame-relay mfr 1
no shut
int s0/1
shutdown
encapsulation frame-relay mfr 1
no shut
int mfr1.12 point-to-point
ip address 172.16.10.2 255.255.255.0
frame-relay interface-dlci 47

 

Test Ping

R1#ping 172.16.10.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.10.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/5/16 ms

 

 

  • PPP Multilink

Now lets look into getting multilink PPP operational. We are going to use interface S0/2 and S0/3 on both devices.

R1
int mfr1.12 point-to-point
no ip address
interface Multilink1
ip address 172.16.10.1 255.255.255.0
ppp multilink
ppp multilink group 1
int s0/2
shutdown
encapsulation ppp
ppp multilink
ppp multilink group 1
no shut
int s0/3
shutdown
encapsulation ppp
ppp multilink
ppp multilink group 1
no shut

R2
int mfr1.12 point-to-point
no ip address
interface Multilink1
ip address 172.16.10.2 255.255.255.0
ppp multilink
ppp multilink group 1
int s0/2
shutdown
encapsulation ppp
ppp multilink
ppp multilink group 1
no shut
int s0/3
shutdown
encapsulation ppp
ppp multilink
ppp multilink group 1
no shut

 

Lets Test again

R1#ping 172.16.10.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.10.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/5/16 ms

 

 

I will soon add Virtual-Template into this post so we’ll have it all in one piece

 

Would anyone want to do this in the real world?  I hope not 🙂 but it will most likely appear in your R&S lab !

Enjoy !

Tom