Multipath Operation

Overview of Multipath operation

From IEC6400 Release 1.1.0, Multipath Operation (MPO) is supported on the IEC6400 gateway. MPO is a patented technology that enables the simultaneous transmission of high-priority packets over multiple paths. It enhances the reliability and efficiency of wireless communication in fast-moving mobile systems like trains, buses, and other vehicles.


Note

  • Gateway licensing policy enables the MPO feature for all license levels.

  • Gateway supports up to four redundant paths for MPO-protected traffic.

  • Gateway supports receiving duplicate packets. However, the number of replicas is decided by mobile nodes.

  • MPO is supported only in Fluidity MPLS Layer 2 configurations.

Overview of MPO data redundancy

The MPO data redundancy enhances the availability and reliability of wireless communication systems. Each wireless link replicates MPO-protected traffic. Even if one wireless link fails, the other links continue to replicate the traffic. This method ensures uninterrupted communication.

Advantages of MPO

  • It is useful in environments where network conditions are dynamic and can lead to packet losses.

  • It distributes traffic across multiple paths to optimize network performance.

  • It removes duplicate packets, so only one copy is processed, reducing unnecessary load.

  • It sorts packets by priority by sending critical packets through multiple paths and non-critical packets through a single path.

MPO packet duplication and deduplication

Duplication

MPO sends the same data across multiple paths in the network. This increases the chances of the data reaching its destination even if some paths fail. It sends duplicate packets using multiple wireless paths to different devices. This enhances the chances of successful packet reception, even if some paths experience losses or delays.


Note

For upstream traffic, gateway is in charge of managing the deduplication, whereas duplication is performed only on wireless links by IW devices. For downstream traffic, the roles are inverted.

Deduplication

This process ensures that only one copy of each packet is processed, even if multiple copies are received. It removes duplicate packets using sequence numbers assigned to the packets.

Figure 1. Process of Duplication and Deduplication

Duplication and Deduplication algorithm:

  • Handles packet loss and paths with high or variable delays.

  • Removes additional packet delays created by buffering.

  • Removes duplicate and out-of-sequence packets.

Manage MPO parameters using CLI

Perform these steps to enable MPO, manage MPO CoS, and MPO telemetry.


Note

By default, this feature is disabled on the gateway.

Procedure

Step 1

Use the fluidity mpo status enable command to enable the MPO feature on the gateway. 

Device#fluidity mpo status enable

Note

 

Use the fluidity mpo status disable command to disable the MPO feature on the gateway.

Step 2

Use the fluidity mpo cos CoS value command to manage MPO Class-of-Service (CoS) on the gateway. 

Device#fluidity mpo cos C

Configure class-of-service (CoS) of traffic to protect with MPO redundancy, you can use only one CoS at a time. Valid cos range is from zero to seven and the default value is six.

Step 3

Use the fluidity mpo telemetry enable command to enable MPO telemetry on the gateway. 

Device#fluidity mpo telemetry enable

Note

 

  • Use the fluidity mpo telemetry disable command to disable MPO telemetry on the gateway.

  • By default, MPO telemetry is disabled on the gateway.

Step 4

Use the write command to apply the configuration in a permanent way. 

Device#write

Step 5

Use the reboot command to reboot the device. 

Device#reboot

Manage rx-only MPO from CLI

Rx-Only deduplicates incoming MPLS traffic. However, it does not duplicate outgoing traffic.

Use the fluidity mpo status rx-only command to enable RX-Only on the gateway. 

Device#fluidity mpo status rx-only

MPO configuration example

Device#fluidity mpo status enabled
Device#fluidity mpo cos 6
Device#fluidity mpo telemetry 1
Device#write
Device#reboot

Verify MPO configuration from CLI

Use the fluidity mpo command to view the status of MPO configuration on the gateway. 

Device#fluidity mpo
Status: enabled
CoS: 6
Telemetry: enabled

Verify MPLS configuration from CLI

Use the mpls command to view the status of MPLS configuration on the gateway. 

Device#mpls
layer 2
unicast-flood: enabled (limited rate)
arp-unicast: enabled (broadcasting not allowed)
reduce-broadcast: disabled
pwlist: all
Cluster ID: disabled
Ethernet Filter allow-list: 0x8892 0x8204, ethernet-I block
MPLS fast failover:  enabled
Node failover timeout:  50 ms
L2TP WAN update delay:  100 ms
Preemption delay:  100 s
Virtual IP:  0.0.0.0
ARP limit: rate 0 grace 30000 block 0

MPLS tunnels:
ldp_id 1365673902 debug 0 auto_pw 1
local_gw 5.27.50.238 global_gw 0.0.0.0 pwlist { }
mobility true vehicle_id -2 v2v_handoff 0 v2v_pws false auto_en true static_pws { 0.0.0.0 }
lsps 2
<5.27.50.238 5.212.77.176 233907170> ESTABLISHED ftn 256 ilm 178016 pim- 46.364051233 ka 0 { 5.27.50.238 5.81.160.244 5.212.77.176 }
<5.27.50.238 5.81.160.244 1316742122> ESTABLISHED ftn 1 ilm 178015 pi-- 2.383096885 ka 0 { 5.27.50.238 5.81.160.244 }
MPLS Multipath tunnels:
5.212.77.176:
    path_id 0 ilm 178016 nhlfe 48 lbr 5.81.160.244 age 46.432595279 { 5.27.50.238 5.81.160.244 5.212.77.176 }
    path_id 1 ilm 178017 nhlfe 50 lbr 5.81.160.244 age 46.421394799 { 5.27.50.238 5.81.160.244 5.212.77.176 }

Verify fluidity MPO statistics from CLI

Use the fluidity mpo statistics command to view the MPO fluidity statistics of the gateway. 

Device#fluidity mpo statistics
table-size 2:
MAC address : 40:36:5A:15:C8:50 8C:89:A5:83:EB:71
Tx-1 : 0 208
Tx-2 : 0 208
Rx-Accept-1 : 178 0
Rx-Accept-2 : 30 0
Rx-Drop-1 : 30 0
Rx-Drop-2 : 178 0
Lost-1-only : 0 0
Lost : 0 0

MPO Statistics

Description

MAC address

The source Layer 2 address of the external network device that sends packets.

Tx-1 and Tx-2

Shows the total count of packets that are eligible for duplication.

Rx-Accept-1 and Rx-Accept-2

Shows the total count of packets received and dropped during the de-duplication process. This can happen on either the primary or secondary path.

Lost-1-only

Shows the total count of packets received and accepted during the de-duplication process on the secondary path.

Lost

Shows the cumulative number of packets lost on both the primary and secondary paths.