MPPPoFR + LFI

Principe
- A dual FIFO is created on the physical interface to interleave priority packet with fragmented packet

Prerequiste :
- Needs a service-policy with LLQ
- Needs FRTS on the serial interface
- Configure a Virtual-template with ppp multilink interleave and ppp multilink fragment.
- Optionnaly ppp multilink multiclass should be activated if there is multiple links.

To know :
- The configured delay is used by IOS to calculate the fragment size. (in this case 128/8 = 16kb)
- The serialization delay will be calculated according to the physical link speed (in this case 16/2000 = 8ms)
- In case of multilink, multiclass is needed in order to force priority packet to also have the MPPP header and be reordered.

interface Virtual-Template1
bandwidth 128
ip unnumbered Loopback1
ppp multilink
ppp multilink interleave
ppp multilink fragment delay 125
service-policy output QOS

interface Serial0/0
no ip address
encapsulation frame-relay
no keepalive
clock rate 2000000
frame-relay traffic-shaping
frame-relay interface-dlci 102 ppp Virtual-Template1

sh ppp multi

With a single link :

Virtual-Access3
Bundle name: Router
Remote Endpoint Discriminator: [1] Router
Local Endpoint Discriminator: [1] Router
Bundle up for 00:34:33, total bandwidth 256, load 3/255
Receive buffer limit 24384 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
0x6C8 received sequence, 0x891E sent sequence
Member links: 1 (max not set, min not set)
Vi1, since 00:34:33, 2048 weight, 1496 frag size
No inactive multilink interfaces


Router(config-if)#do sh int s0/0
Serial0/0 is up, line protocol is up
Hardware is GT96K Serial
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY, loopback not set
Keepalive not set
CRC checking enabled
LMI DLCI 1023 LMI type is CISCO frame relay DTE
FR SVC disabled, LAPF state down
Broadcast queue 0/64, broadcasts sent/dropped 0/0, interface broadcasts 0
Last input 04:04:29, output 00:00:04, output hang never
Last clearing of "show interface" counters 04:04:27
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: dual fifo
Output queue: high size/max/dropped 0/256/0




With Multilink multiclass :

interface Serial0/0
no ip address
encapsulation frame-relay
no keepalive
clock rate 2000000
frame-relay traffic-shaping
frame-relay interface-dlci 102 ppp Virtual-Template1
frame-relay interface-dlci 103 ppp Virtual-Template1
no shut


interface multilink1
ppp multi multiclass
band 128
ip unnumbered Loopback1
ppp multilink interleave
ppp multilink fragment delay 125
service-policy output QOS

int virtual-template 1
ppp multilink group 1

Virtual-Access4
Bundle name: Router
Remote Endpoint Discriminator: [1] Router
Local Endpoint Discriminator: [1] Router
Bundle up for 00:02:59, total bandwidth 256, load 1/255, 2 receive classes, 2 transmit classes
Receive buffer limit 24384 bytes per class, frag timeout 1000 ms
Interleaving enabled
Receive Class 0:
0/0 fragments/bytes in reassembly list
0 lost fragments, 0 reordered
0/0 discarded fragments/bytes, 0 lost received
0x40 received sequence
Receive Class 1:
0/0 fragments/bytes in reassembly list
0 lost fragments, 0 reordered
0/0 discarded fragments/bytes, 0 lost received
0xBBB received sequence
Transmit Class 0:
0x37 sent sequence
Transmit Class 1:
0x6D sent sequence
Member links: 2 (max not set, min not set)
Vi1, since 00:03:01, 2048 weight, 1496 frag size
Vi3, since 00:03:00, 2048 weight, 1496 frag size
No inactive multilink interfaces



http://www.cisco.com/en/US/docs/ios/wan/configuration/guide/wan_frque_frag_if_ps6350_TSD_Products_Configuration_Guide_Chapter.html

http://blog.ine.com/2008/01/26/ppp-multilink-interleaving-over-frame-relay/