Packet mis-ordering prevention in source routing hitless reroute using inter-packet delay and precompensation

Patent metadata

Field	Value
Publication number	US-10142248-B2
Application number	US-201514869110-A
Country	US
Kind code	B2
Filing date	Sep 29, 2015
Priority date	Sep 29, 2015
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

A method implemented by a network element (NE), comprising forwarding one or more initial packets in a packet flow from a source to a destination along an initial route having an initial route packet delay, obtaining an updated route having an updated route packet delay less than the initial route packet delay, and delaying transmission of a subsequent packet over the updated route by an amount of time determined in accordance with the initial route packet delay, the updated route packet delay and an inter-packet delay associated with the packet flow.

First claim

What is claimed is:

1. A method implemented by a network element (NE), comprising:
forwarding one or more initial packets in a packet flow from a source to a destination along an initial route having an initial route packet delay;
obtaining an updated route having an updated route packet delay less than the initial route packet delay; and
delaying transmission of a subsequent packet in the packet flow over the updated route by an amount of time determined in accordance with the initial route packet delay, the updated route packet delay, and an inter-packet delay when a path delay difference between the initial route packet delay and the updated route packet delay is greater than the inter-packet delay, the inter-packet delay being a delay between successive packets in the packet flow.

2. The method of claim 1 , further comprising:
subtracting the updated route packet delay and the inter-packet delay from the initial route packet delay to produce a delay difference;
determining that the delay difference is greater than zero; and
delaying the transmission of the subsequent packet by a duration greater than the delay difference.

3. The method of claim 2 , wherein the initial route packet delay is denoted as delay (P old ), wherein the updated route packet delay is denoted as delay (P new ), wherein the inter-packet delay is denoted as τ, wherein the method further comprises determining the amount of time to delay the transmission of the subsequent packet, denoted as dt, by computing operations:

{

dt
=

delay
⁡

(

P
old

)

-

delay
⁡

(

P
new

)

-
τ
+
ɛ

,

if
⁢

⁢

delay
⁡

(

P
old

)

-

delay
⁡

(

P
new

)

>
τ

,

dt
=
0

,

if
⁢

⁢

delay
⁡

(

P
old

)

-

delay
⁡

(

P
new

)

≤
τ

,

and wherein ε is a positive value greater than zero.

4. The method of claim 1 , wherein obtaining the updated route comprises receiving a reroute message instructing the NE to reroute the packet flow from the initial route to the updated route, and wherein the reroute message comprises an inter-packet delay utilization flag indicating that the NE is allowed to utilize the inter-packet delay when determining the amount of time to delay the transmission of the subsequent packet such that packet mis-ordering is prevented in the packet flow.

5. The method of claim 1 , further comprising:
subtracting the updated route packet delay and the inter-packet delay from the initial route packet delay to produce a delay difference;
determining that the delay difference is greater than zero;
delaying the transmission of the subsequent packet over the updated routed by a duration of a first portion of the delay difference; and
delaying transmissions of the initial packets over the initial route according to a second portion of the delay difference.

6. The method of claim 5 , wherein delaying the transmissions of the initial packets over the initial route further comprises increasingly delaying the transmissions of the initial packets over the initial route such that the initial packets forwarded over the initial route arrive at the destination in increasing time intervals.

7. The method of claim 1 , further comprising:
determining that the inter-packet delay associated with the packet flow is about zero; and
delaying transmissions of the initial packets over the initial route to create inter-packet delays between

Assignees

• Huawei Tech Co Ltd

Inventors

• Akhavain Mohammadi Mehdi Arashmid

Classifications

• H04L45/74

  Address processing for routing · CPC title

• H04L45/22

  Alternate routing · CPC title

• H04L45/121

  by minimising delays · CPC title

• H04L45/72

  Routing based on the source address · CPC title

• H04L47/32 Primary

  by discarding or delaying data units, e.g. packets or frames · CPC title