Quick Notes - QoS - Serialization Delay MLPPP

Mutlilink  PPP fragments traffic by default and this can be leveraged by QOS. To reduce serialization delay perform the following:

Create multilink interface

interface multilink 1
 ip address 1.1.1.1 255.255.255.0
 ppp multilink (this enables fragmentation on the multilink interface)
 ppp multilink interleave (this enables interleaving)
 ppp fragment-delay [delay] (specifies how long the fragment will take to leave the interface in milliseconds)

Assign the virtual template to the physical interface

interface serial 0/0/0
 encapsualtion ppp
 multilink-group 1

R1
__
interface Multilink1
 ip address 1.1.1.1 255.255.255.0
 ppp multilink
 ppp multilink fragment delay 10
 ppp multilink interleave
 ppp multilink group 1
end

interface Serial1/0
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
end

R2
__
interface Multilink1
 ip address 1.1.1.2 255.255.255.0
 ppp multilink
 ppp multilink fragment delay 10
 ppp multilink interleave
 ppp multilink group 1
end

interface Serial1/2
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
end

R2(config-if)#do show ppp multilink

Multilink1, bundle name is R1
  Endpoint discriminator is R1
  Bundle up for 00:01:40, total bandwidth 1544, 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
    0x7 received sequence, 0x7 sent sequence
  Member links: 1 active, 1 inactive (max not set, min not set)
    Se1/0, since 00:01:41, 1930 weight, 1496 frag size
    Vt1 (inactive)
No inactive multilink interfaces

Disabled!! but....... well you have to use a policy map and set the bandwidth.

class-map match-all CMAP
 match any
policy-map PMAP
 class CMAP
  bandwidth 512
interface Multilink1
 service-policy output PMAP

R2(config)#do sh ppp multilink

Multilink1, bundle name is R1
  Endpoint discriminator is R1
  Bundle up for 00:22:25, total bandwidth 1544, load 1/255
  Receive buffer limit 12000 bytes, frag timeout 1000 ms
  Interleaving enabled
    0/0 fragments/bytes in reassembly list
    0 lost fragments, 0 reordered
    0/0 discarded fragments/bytes, 0 lost received
    0x1C received sequence, 0x1C sent sequence
  Member links: 1 active, 1 inactive (max not set, min not set)
    Se1/0, since 00:17:28, 1930 weight, 1496 frag size
    Vt1 (inactive)
No inactive multilink interfaces

Thats better!