# US 11,444,860 B2 · Automating and extending path tracing through wireless links

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- Number: US 11,444,860 B2
- Document ID: US11444860B2
- Status: Granted
- Kind: B2
- Application number: 17/031,312
- Filed: 2020-09-24
- Published: 2022-03-24
- Granted: 2022-09-13
- Earliest claimed: 2020-09-24
- Assignees: Cisco Technology, Inc.
- Applicants: Cisco Technology, Inc.
- Inventors: Thomas Szigeti; Jerome Henry; Robert E. Barton; Malcolm M. Smith
- Web page: https://patentgrep.com/patent/US11444860B2

## CPC

- H04L 43/0864: Round trip delays
- H04L 43/0817: by checking functioning
- H04L 43/0858: {One way delays}
- H04L 43/0894: Packet rate
- H04L 43/10: Active monitoring, e.g. heartbeat, ping or trace-route
- H04W 24/04: Arrangements for maintaining operational condition
- H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports}
- H04W 84/12: WLAN [Wireless Local Area Networks]
- H04W 24/08: Testing, {supervising or monitoring} using real traffic
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Automating and extending path tracing through wireless links is provided by receiving a request to perform a network trace over a wireless link provided by an Access Point (AP) configured as a transparent forwarder between a trace source and a trace target; monitoring a trace packet from a first time of arrival at the AP, a first time of departure from the AP, a second time of arrival at the AP, and a second time of departure from the AP; monitoring a buffer status of the AP at the first time of arrival and the second time of arrival; and in response to identifying a network anomaly based on the trace packet and the buffer status, adjusting a network setting at the AP.

## Claims

### Claim 1

A method, comprising:
receiving a request to perform a network trace over a wireless link provided by an Access Point (AP) configured as a transparent forwarder between a trace source and a trace target;
monitoring a trace packet from a first time of arrival at the AP, a first time of departure from the AP, a second time of arrival at the AP, and a second time of departure from the AP;
monitoring a buffer status of the AP at the first time of arrival and the second time of arrival; and
in response to identifying a network anomaly based on the trace packet and the buffer status, adjusting a network setting at the AP.

### Claim 2 (depends on 1)

The method of claim 1, wherein the wireless link connects the AP to the trace target, wherein the AP receives an inbound trace packet at the first time of arrival and receives an outbound trace packet at the second time of arrival.

### Claim 3 (depends on 1)

The method of claim 1, wherein the wireless link connects the AP to the trace source, wherein the AP receives an outbound trace packet at the first time of arrival and receives an inbound trace packet at the second time of arrival.

### Claim 4 (depends on 3)

The method of claim 3, wherein the trace source reports a third time of arrival of the inbound trace packet at the trace source in a subsequent transmission from the trace target to the AP.

### Claim 5 (depends on 1)

The method of claim 1, wherein the wireless link connects the AP to a second AP.

### Claim 6 (depends on 1)

The method of claim 1, wherein monitoring the trace packet identifies processing asymmetries on the AP between an uplink processing time and a downlink processing time, wherein the uplink processing time is a first time period between the first time of arrival and the first time of departure, wherein the downlink processing time is a second time period between the second time of arrival and the second time of departure, wherein adjusting the network setting includes signaling wireless clients of the AP to handoff to a different AP.

### Claim 7 (depends on 6)

The method of claim 6, further comprising:
surfacing a client contribution to a network delay based on a ratio between a client handling time and the buffer status, wherein the client handling time occurs between the first time of departure and the second time of arrival.

### Claim 8

A system, comprising:
a processor; and
a memory device including instructions that when executed by the processor perform an operation including:
receiving a request to perform a network trace over a wireless link provided by an Access Point (AP) configured as a transparent forwarder between a trace source and a trace target;
monitoring a trace packet from a first time of arrival at the AP, a first time of departure from the AP, a second time of arrival at the AP, and a second time of departure from the AP;
monitoring a buffer status of the AP at the first e of arrival and the second time of arrival; and
in response to identifying a network anomaly based on the trace packet and the buffer status, adjusting a network setting at the AP.

### Claim 9 (depends on 8)

The system of claim 8, wherein the wireless link connects the AP to the trace target, wherein the AP receives an inbound trace packet at the first time of arrival and receives an outbound trace packet at the second time of arrival.

### Claim 10 (depends on 8)

The system of claim 8, wherein the wireless link connects the AP to the trace source, wherein the AP receives an outbound trace packet at the first time of arrival and receives an inbound trace packet at the second time of arrival.

### Claim 11 (depends on 10)

The system of claim 10, wherein the trace source reports a third time of arrival of the inbound trace packet at the trace source in a subsequent transmission from the trace target to the AP.

### Claim 12 (depends on 8)

The system of claim 8, wherein the wireless link connects the AP to a second AP.

### Claim 13 (depends on 8)

The system of claim 8, wherein monitoring the trace packet identifies processing asymmetries on the AP between an uplink processing time and a downlink processing time, wherein the uplink processing time is a first time period between the first time of arrival and the first time of departure, wherein the downlink processing time is a second time period between the second time of arrival and the second time of departure, wherein adjusting the network setting includes signaling wireless clients of the AP to handoff to a different AP.

### Claim 14 (depends on 13)

The system of claim 13, the operation further including:
surfacing a client contribution to a network delay based on a ratio between a client handling time and the buffer status, wherein the client handling time occurs between the first time of departure and the second time of arrival.

### Claim 15

A memory device including computer readable instructions that when executed by a processor perform an operation comprising:
receiving a request to perform a network trace over a wireless link provided by an Access Point (AP) configured as a transparent forwarder between a trace source and a trace target;
monitoring a trace packet from a first time of arrival at the AP, a first time of departure from the AP, a second time of arrival at the AP, and a second time of departure from the AP;
monitoring a buffer status of the AP at the first time of arrival and the second time of arrival; and
in response to identifying a network anomaly based on the trace packet and the buffer status, adjusting a network setting at the AP.

### Claim 16 (depends on 15)

The memory device of claim 15, wherein the wireless link connects the AP to the trace target, wherein the AP receives an inbound trace packet at the first time of arrival and receives an outbound trace packet at the second time of arrival.

### Claim 17 (depends on 15)

The memory device of claim 15, wherein the wireless link connects the AP to the trace source, wherein the AP receives an outbound trace packet at the first time of arrival and receives an inbound trace packet at the second time of arrival, and wherein the trace source reports a third time of arrival of the inbound trace packet at the trace source in a subsequent transmission from the trace target to the AP.

### Claim 18 (depends on 15)

The memory device of claim 15, wherein the wireless link connects the AP to a second AP.

### Claim 19 (depends on 15)

The memory device of claim 15, wherein monitoring the trace packet identifies processing asymmetries on the AP between an uplink processing time and a downlink processing time, wherein the uplink processing time is a first time period between the first time of arrival and the first time of departure, wherein the downlink processing time is a second time period between the second time of arrival and the second time of departure, wherein adjusting the network setting includes signaling wireless clients of the AP to handoff to a different AP.

### Claim 20 (depends on 19)

The memory device of claim 19, further comprising:
surfacing a client contribution to a network delay based on a ratio between a client handling time and the buffer status, wherein the client handling time occurs between the first time of departure and the second time of arrival.